GCSE in CHEMISTRY Specimen Assessment Materials 1
For teaching from 2011
GCSE in CHEMISTRY
SPECIMEN ASSESSMENT MATERIALS
GCSE in CHEMISTRY Specimen Assessment Materials 3
Contents
Page
Unit 1
Question Paper (Foundation Tier)
5
Question Paper (Higher Tier)
25
Mark Schemes
41
Assessment Grids
55
Unit 2
Question Paper (Foundation Tier)
59
Question Paper (Higher Tier)
75
Mark Schemes
91
Assessment Grids
105
Unit 3
Question Paper (Foundation Tier)
109
Question Paper (Higher Tier)
127
Mark Schemes
145
Assessment Grids
159
Controlled Assessment
163
GCSE in CHEMISTRY Specimen Assessment Materials 5
Candidate Name
Centre Number
Candidate Number
0
GCSE
CHEMISTRY
FOUNDATION TIER (Grades G-C)
CHEMISTRY 1 – The Earth and its resources
SPECIMEN PAPER
(1 hour)
INSTRUCTIONS TO CANDIDATES
Write your name, centre number and candidate number in the spaces at the top of this
page.
Answer all questions.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded that assessment will take into account the quality of written
communication used in your answer to question 10.
GCSE in CHEMISTRY Specimen Assessment Materials 6
Answer all questions.
1.
(a)
The key below represents atoms of some elements.
(i)
The gas methane has the formula CH4.
Choose the letter of the diagram below that represents a molecule of
methane.
[1]
Letter ..................................
(ii)
(b)
Use the key given above to draw diagrams representing the
molecules
I hydrogen, H2,
[1]
II ammonia, NH3.
[1]
The chemical formula of carbonic acid is H2CO3.
(i)
State how many carbon atoms are present in the formula H2CO3.
....................
(ii)
[1]
Give the total number of atoms shown in the formula.
....................
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 7
2.
(i)
The box below shows the names of some gases found in the atmosphere.
argon
carbon dioxide
neon
nitrogen
oxygen
Choose gases from the box above to answer parts I and II.
Each gas can be used once, more than once, or not at all.
Name the
I
two gases kept in balance in the atmosphere by the two processes of
respiration and photosynthesis,
................................................ and ................................................ [1]
II
gas which most scientists believe is mainly responsible for global
warming.
...................................................................................
(ii)
[1]
In the 1960s, Alfred Wegener's idea that all the continents were once joined
together as one big land mass was accepted by other scientists.
earthquakes
similar patterns of fossils
ocean currents
shapes of continents
Choose from the box above two types of evidence that Wegener used to
support his idea.
1. ...........................................................................
2. ...........................................................................
[2]
GCSE in CHEMISTRY Specimen Assessment Materials 8
3.
The diagrams below show stages in making the compound copper sulfate by reacting
copper carbonate with dilute sulfuric acid.
(i)
State why copper carbonate is added in excess.
[1]
............................................................................................................................
(ii)
boiling
evaporating
dissolving
filtering
Choose, from the box above, the name for the process occurring in:
(iii)
I
Stage 2 ................................................................
[1]
II
Stage 3 ................................................................
[1]
The reaction that takes place in stage 1 can be described by the following
word equation.
sulfuric
acid
I
+
copper
carbonate
l
copper
sulfate
+
+
Choose, from the box below, the name of the group of compounds to
which copper sulfate belongs.
acid
base
……………………………………………………..
II
water
carbon
dioxide
salt
[1]
All of the substances in the above equation are compounds. State
how compounds are different to elements.
[1]
................................................................................................................
(iv)
If sodium carbonate were used instead of copper carbonate, give the
chemical name of the crystals formed in the evaporating basin in stage 3. [1]
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 9
4.
Acid rain is an increasing environmental problem. One of the causes is the
production of nitrogen oxides.
(i)
The pie chart below shows the sources of the nitrogen oxides present in the
atmosphere.
Use the information in the chart to calculate the percentage of nitrogen oxides
present in the atmosphere due to road transport.
[1]
............................................................................................................................
............................................................................................................................
(ii)
State two ways in which acid rain affects the environment.
[2]
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 10
(iii)
The table below shows the amount of nitrogen oxides released into the
atmosphere in the year shown.
Year
thousand tonnes
1970
2501
1980
2581
1990
2759
2000
1737
Since 1993, all new cars have been fitted with a catalytic converter. Catalytic
converters remove nitrogen oxides from car exhaust gases by passing them
over a platinum catalyst.
I
Suggest why the amount of nitrogen oxides released into the
atmosphere increased between 1970 and 1990.
....................................................................................................
II
[1]
Describe how the data in the table above can be used to support the
view that catalytic converters are effective.
[2]
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 11
5.
A small piece of magnesium ribbon was placed into excess dilute hydrochloric acid in
a boiling tube. The temperature of the reaction mixture was recorded using a
temperature sensor and displayed on a computer screen.
GCSE in CHEMISTRY Specimen Assessment Materials 12
(a)
(i)
Use the graph to answer parts I and II.
I
State the time taken for the reaction to come to an end.
[1]
.................... seconds
II
State the maximum temperature rise recorded during the reaction.
[1]
...........................................................................................................
(ii)
Give one advantage of using a temperature sensor and computer to
record the temperature.
[1]
...............................................................................................................
...............................................................................................................
(b)
(i)
Other than the temperature change, give two observations which
suggest that a chemical change is occurring when magnesium is
added to dilute acid.
[2]
...............................................................................................................
...............................................................................................................
(ii)
The following table shows the colours of universal indicator at different
pH ranges.
Colour
Red
Orange
Yellow
Green
Blue
Navy Blue
Purple
pH range
0-2
3-4
5-6
7
8-9
10-12
13-14
One of the products of the reaction is magnesium chloride.
Magnesium chloride solution is neutral. Give the colour of universal
indicator in magnesium chloride solution.
[1]
Colour ..................................
GCSE in CHEMISTRY Specimen Assessment Materials 13
6.
(i)
State why a nano-sized particle of a given substance could be considered to
be a different material and why it could therefore have different uses.
[1]
............................................................................................................................
(ii)
A newspaper reported that 'nano-sized particles could have negative effects
in the long-term on health and the environment'.
Chemists are currently developing nano-scale materials for use in solar cells
which could provide a major development in our ability to provide electricity
using the sun's energy.
Describe the potential benefits of this research and discuss whether or not, in
your opinion, those benefits outweigh the potential risk involved.
[3]
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 14
7.
This question is about the reactivity of metals.
(a)
A teacher carried out the following two experiments in a fume cupboard.
Experiment 1
A mixture of aluminium powder and iron oxide was heated strongly using the
equipment shown.
The reaction that took place can be summarised by the following word
equation.
aluminium
+
iron oxide
→
aluminium oxide
+
iron
Experiment 2
The above experiment was then repeated using a mixture of iron powder and
copper oxide.
The word equation for this reaction is shown below.
iron
(i)
+
copper oxide
→
iron oxide
+
Use the results of the two reactions to place the three metals,
aluminium, copper and iron in order of decreasing reactivity.
copper
[2]
Most reactive ..........................................................
..........................................................
..........................................................
(ii)
The teacher said that iron oxide, in Experiment 1, and copper oxide, in
Experiment 2, had both been reduced.
State the meaning of the term reduced.
[1]
................................................................................................................
................................................................................................................
................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 15
(b)
Zinc is more reactive than copper.
Excess zinc powder was added to blue copper sulfate solution.
During the reaction, the blue solution became colourless and a brown solid
was formed.
(i)
Name the colourless solution A.
[1]
.................................................
(ii)
Name the brown solid B.
.................................................
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 16
8.
(a)
The table below shows some physical properties of Group 1 elements.
Element
Melting point
/ °C
Boiling point
/ °C
Density
/ gcm-3
Electrical
conductivity
lithium
sodium
potassium
rubidium
caesium
180
1340
880
766
686
669
0.50
0.97
0.86
1.50
1.90
good
good
good
good
good
63
39
29
Use only the information in the table to answer parts (i) and (ii).
(i)
State the property of Group 1 metals which is common to all metals.
[1]
.........................................................................................................
(ii)
Predict the approximate value for the melting point of sodium and give
a reason for your choice.
[2]
Melting point .......................... °C
Reason ..................................................................................................
................................................................................................................
(b)
Sodium reacts vigorously with fluorine to give sodium fluoride as shown in the
following word equation.
sodium
+ fluorine
sodium fluoride
Balance the symbol equation shown below.
Na
+
F2
[2]
NaF
GCSE in CHEMISTRY Specimen Assessment Materials 17
(c)
Sodium fluoride is added to the water supply in some areas because fluoride
ions have been shown to cause a reduction in tooth decay.
Scientists established this link by carrying out large scale surveys.
(i)
Give a reason why scientists required large numbers of people to
complete their surveys in order to establish the link between fluoride
ions and a reduction in tooth decay.
[1]
................................................................................................................
................................................................................................................
(ii)
Suggest why it would be better for this type of survey to be carried out
by an independent consumer group rather than by a company which
manufactures toothpaste.
[1]
................................................................................................................
................................................................................................................
(iii)
Give one reason why many people are against the fluoridation of the
water supply.
[1]
................................................................................................................
................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 18
9.
John and Betsan wanted to investigate the link between the number of carbon atoms
present in molecules of different fuels and the amount of heat they released on
burning.
They were told that molecules of fuels A-E had the following numbers of carbon
atoms.
Fuel
A
B
C
D
E
Number of carbon atoms per molecule
1
2
3
4
5
They decided to use the apparatus below to make their measurements.
They recorded the initial temperature of the water and lit the burner. They placed the
burner below the flask and heated the water for 1 minute. They then removed the
burner and noted the highest temperature recorded on the thermometer.
GCSE in CHEMISTRY Specimen Assessment Materials 19
(i)
In addition to the heating time, name one of the variables that they should
keep constant during each of their experiments in order to ensure that their
results are valid.
[1]
..........................................................................................................................
They collected the following results for fuels A-D but did not have a sample of
fuel E to test.
Fuel
Temperature of water (°C)
Initial
Final
Increase
Number of carbon atoms per
molecule
1
2
3
4
5
A
B
C
D
E
19
20
20
19
29
32
35
38
10
12
15
(ii)
Calculate, and record in the table, the increase in temperature for fuel D.
(iii)
Plot a graph to show the relationship between the number of carbon atoms
per molecule and the temperature increase when each fuel is burned for
1 minute.
[3]
Temperature
increase
/ ºC
0
1
2
3
4
Number of carbon atoms
5
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 20
(iv)
Describe the general trend shown by your graph.
[1]
............................................................................................................................
(v)
Use your graph to predict the temperature increase which would be produced
by burning fuel E for 1 minute.
[1]
........................................ºC
(vi)
Betsan told John they should try to find out whether or not the results are
'repeatable'. Describe how they should do so.
[1]
............................................................................................................................
............................................................................................................................
(vii)
State what you think is the most likely reason that the values they measured
are not the true values. Suggest how the method used could be changed in
order to improve the quality of the results.
[2]
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 21
10.
It has been suggested that waste plastics could be recycled and used to manufacture
houses cheaply and quickly.
Evaluate this potential use of waste plastics.
[6 QWC]
In your answer you should refer to
• the properties of plastics
• what happens to most plastics once they have been used
• the need to make the best possible use of the Earth's natural resources
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 22
FORMULAE FOR SOME COMMON IONS
POSITIVE IONS
NEGATIVE IONS
NAME
FORMULA
NAME
FORMULA
Aluminium
Al3+
Bromide
Br-
Ammonium
NH4+
Carbonate
CO32-
Barium
Ba2+
Chloride
CI-
Calcium
Ca2+
Fluoride
F-
Copper(II)
Cu2+
Hydroxide
OH-
Hydrogen
H+
Iodide
I-
Iron(II)
Fe2+
Nitrate
NO3-
Iron(III)
Fe3+
Oxide
O2-
Lithium
Li+
Sulfate
SO42-
Magnesium
Mg2+
Nickel
Ni2+
Potassium
K+
Silver
Ag+
Sodium
Na+
GCSE in CHEMISTRY Specimen Assessment Materials 23
GCSE in CHEMISTRY Specimen Assessment Materials 25
Candidate Name
Centre Number
Candidate Number
0
GCSE
CHEMISTRY
HIGHER TIER (Grades D-A*)
CHEMISTRY 1 – The Earth and its resources
SPECIMEN PAPER
(1 hour)
INSTRUCTIONS TO CANDIDATES
Write your name, centre number and candidate number in the spaces at the top of this
page.
Answer all questions.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded that assessment will take into account the quality of written
communication used in your answer to questions 3 and 9(c).
GCSE in CHEMISTRY Specimen Assessment Materials 26
Answer all questions.
1.
(a)
The table below shows some physical properties of Group 1 elements.
Element
Melting point
/ °C
Boiling point
/ °C
Density
/ gcm-3
Electrical
conductivity
lithium
sodium
potassium
rubidium
caesium
180
1340
880
766
686
669
0.50
0.97
0.86
1.50
1.90
good
good
good
good
good
63
39
29
Use only the information in the table to answer parts (i) and (ii).
(i)
State one property of Group 1 metals which is common to all metals. [1]
.............................................................................................................
(ii)
Predict the approximate value for the melting point of sodium and give
a reason for your choice.
[2]
Melting point .......................... °C
Reason ..................................................................................................
................................................................................................................
(b)
Sodium reacts vigorously with fluorine to give sodium fluoride as shown in the
following word equation.
sodium
+
fluorine
sodium fluoride
Balance the symbol equation shown below.
Na
+
F2
[2]
NaF
GCSE in CHEMISTRY Specimen Assessment Materials 27
(c)
Sodium fluoride is added to the water supply in some areas because fluoride
ions have been shown to cause a reduction in tooth decay.
Scientists established this link by carrying out large scale surveys.
(i)
Give a reason why scientists required large numbers of people to
complete their surveys in order to establish the link between fluoride
ions and a reduction in tooth decay.
[1]
................................................................................................................
................................................................................................................
(ii)
Suggest why it would be better for this type of survey to be carried out
by an independent consumer group rather than by a company which
manufactures toothpaste.
[1]
................................................................................................................
................................................................................................................
(iii)
Give one reason why many people are against the fluoridation of the
water supply.
[1]
................................................................................................................
................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 28
2.
John and Betsan wanted to investigate the link between the number of carbon atoms
present in molecules of different fuels and the amount of heat they released on
burning.
They were told that molecules of fuels A-E had the following numbers of carbon
atoms.
Fuel
A
B
C
D
E
Number of carbon atoms per molecule
1
2
3
4
5
They decided to use the apparatus below to make their measurements.
They recorded the initial temperature of the water and lit the burner. They placed the
burner below the flask and heated the water for 1 minute. They then removed the
burner and noted the highest temperature recorded on the thermometer.
GCSE in CHEMISTRY Specimen Assessment Materials 29
(i)
In addition to the heating time, name one of the variables that they should
keep constant during each of their experiments in order to ensure that their
results are valid.
[1]
..........................................................................................................................
They collected the following results for fuels A-D but did not have a sample of
fuel E to test.
Fuel
Temperature of water (°C)
Initial
Final
Increase
Number of carbon atoms per
molecule
1
2
3
4
5
A
B
C
D
E
19
20
20
19
29
32
35
38
10
12
15
(ii)
Calculate, and record in the table, the increase in temperature for fuel D.
(iii)
Plot a graph to show the relationship between the number of carbon atoms
per molecule and the temperature increase when each fuel is burned for
1 minute.
[3]
Temperature
increase
/ ºC
0
1
2
3
4
Number of carbon atoms
5
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 30
(iv)
Describe the general trend shown by your graph.
[1]
............................................................................................................................
(v)
Use your graph to predict the temperature increase which would be produced
by burning fuel E for 1 minute.
[1]
........................................°C
(vi)
Betsan told John that they should try to find out whether or not the results are
'repeatable'. Describe how they should do so.
[1]
............................................................................................................................
............................................................................................................................
(vii)
State what you think is the most likely reason that the values they measured
are not the true values. Suggest how the method used could be changed in
order to improve the quality of the results.
[2]
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 31
3.
It has been suggested that waste plastics could be recycled and used to manufacture
houses cheaply and quickly.
Evaluate this potential use of waste plastics.
[6 QWC]
In your answer you should refer to
• the properties of plastics
• what happens to most plastics once they have been used
• the need to make the best possible use of the Earth's natural resources
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 32
4.
The following graph shows how levels of carbon dioxide in the air have changed
between 1750 and the year 2000.
(i)
Compare the pattern of change shown in the graph before and after 1900. [2]
............................................................................................................................
............................................................................................................................
(ii)
Give one possible reason for the change seen after 1900.
[1]
............................................................................................................................
............................................................................................................................
(iii)
I
Describe what effect these changes in levels of carbon dioxide are
believed to be having on the temperature of the Earth's atmosphere.
[1]
................................................................................................................
II
What is the name given to this effect?
[1]
................................................................................................................
III
Give one possible result of this change in the temperature of the
Earth's atmosphere.
[1]
................................................................................................................
................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 33
5.
(a)
The diagram below shows some reactions of dilute hydrochloric acid.
zinc chloride solution
and gas B
metal A
copper(II) chloride
solution
black
powder D
dilute
hydrochloric acid
sodium hydroxide
solution
colourless solution C
copper(II) carbonate
copper(II) chloride
solution and carbon
dioxide gas
Give the name for
(b)
(i)
metal A,
....................................................................
[1]
(ii)
gas B,
....................................................................
[1]
(iii)
colourless solution C, ....................................................................
[1]
(iv)
black powder D.
[1]
(i)
Describe how you could prepare crystals of copper(II) chloride from
copper(II) carbonate and hydrochloric acid.
[3]
....................................................................
................................................................................................................
................................................................................................................
................................................................................................................
................................................................................................................
................................................................................................................
................................................................................................................
(ii)
Write the formula for copper(II) chloride.
[1]
................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 34
6.
(a)
The following diagram shows how aluminium is extracted from its ore by
electrolysis.
(i)
Give the name of the electrolyte used in this extraction.
[1]
................................................................................................................
(ii)
The word equation for the overall reaction that takes place during the
extraction is shown below.
aluminium oxide
aluminium
+
oxygen
During the reaction, reduction takes place. State the meaning of the
term reduction.
[1]
................................................................................................................
................................................................................................................
(iii)
The extraction of aluminium from its ore uses large amounts of
electricity and is therefore very expensive. State one method of
reducing the cost of aluminium metal.
[1]
................................................................................................................
................................................................................................................
(iv)
Aluminium is a very good conductor of electricity and has a low
density.
Give one use of aluminium which relies on both of these properties.
[1]
................................................................................................................
................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 35
(b)
(i)
Copper coins once contained 97% copper and 1 tonne of 1p and 2p
pieces would amount to about £3000 in total.
Use the graph above to suggest a reason why ‘coppers’ are now
made of steel with a thin copper coating.
[1]
................................................................................................................
................................................................................................................
(ii)
Suggest one reason for the increasing demand for copper in the
‘electronic age’.
[1]
................................................................................................................
................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 36
7.
(a)
Crude oil can be separated into fractions using fractional distillation. The
following table shows some properties of the first three fractions collected.
Fraction
Boiling point
range
Size of
molecules
(No. C atoms)
Colour of
fraction
Ease of burning
A
Up to 80 ºC
1-6
colourless
lights easily and burns
with a clean flame
B
80-150 ºC
6-11
yellow
more difficult to light and
produces some smoke
C
over 150 ºC
11 and above
dark
orange
difficult to ignite and
gives smoky flame
(i)
State the relationship between the number of carbon atoms present in
the molecules of each fraction and its boiling point range.
[1]
............................................................................................................................
............................................................................................................................
(ii)
State which fraction, A, B or C, would be most useful as a fuel, giving
a reason for your answer.
[1]
............................................................................................................................
............................................................................................................................
(b)
Fractions not suitable for use as fuels can be cracked. State the conditions
required for cracking to occur and briefly describe why this is an important
reaction.
[2]
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 37
8.
Metal X is suspected to lie between magnesium and iron in the reactivity series.
Describe, and explain, how you would show this was true using the following
chemicals:
magnesium ribbon, iron filings and metal X
solutions of magnesium nitrate, iron nitrate and the nitrate of metal X.
[4]
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 38
9.
Hydrogen gas is potentially the answer to any future world fuel shortage.
Hydrogen is the most abundant element in the universe and is in plentiful supply on
Earth – combined with oxygen in water molecules.
Electrolysis can be used to split water molecules to produce hydrogen gas, H2, and
oxygen gas, O2.
(a)
State why electrolysis of water produces twice the amount of hydrogen as it
does oxygen.
[1]
............................................................................................................................
............................................................................................................................
(b)
Describe how you would prove that a gas is indeed hydrogen.
[1]
............................................................................................................................
............................................................................................................................
(c)
Use the following data to evaluate the potential of hydrogen as a replacement
for petrol and diesel to fuel cars. A complete response will include reference
to advantages and disadvantages.
[6 QWC]
Source
water
Extraction method
requires electricity
Amount of energy released on burning
large
Product of burning
water vapour
Ease of ignition
ignites easily
State at room temperature and pressure
gas
Stability
forms explosive mixture with air
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 39
FORMULAE FOR SOME COMMON IONS
POSITIVE IONS
NEGATIVE IONS
NAME
FORMULA
NAME
FORMULA
Aluminium
Al3+
Bromide
Br-
Ammonium
NH4+
Carbonate
CO32-
Barium
Ba2+
Chloride
CI-
Calcium
Ca2+
Fluoride
F-
Copper(II)
Cu2+
Hydroxide
OH-
Hydrogen
H+
Iodide
I-
Iron(II)
Fe2+
Nitrate
NO3-
Iron(III)
Fe3+
Oxide
O2-
Lithium
Li+
Sulfate
SO42-
Magnesium
Mg2+
Nickel
Ni2+
Potassium
K+
Silver
Ag+
Sodium
Na+
GCSE in CHEMISTRY Specimen Assessment Materials 40
GCSE in CHEMISTRY Specimen Assessment Materials 41
MARK SCHEMES
GCSE in CHEMISTRY Specimen Assessment Materials 43
General Marking Instructions
1.
Over-rigidity in the interpretation of the mark scheme is not intended and it is
accepted that points may be made in a variety of different ways including converse
and counterpoints.
2.
Phonetic spelling is allowed except where there is a possibility that scientific terms
might be confused.
3.
When candidates list alternative answers to short answer questions, the general
principle to be followed is: right + wrong = no mark. In a question requiring a set
number of responses, where a candidate has supplied extra responses above the
required number each error/contradiction negates one correct response, however
responses considered neutral (ie not incorrect) are not penalised.
4.
The principle of error carried forward is generally applied where an incorrect value
calculated in one part of a question is treated as being correct for the purposes of
subsequent parts.
5.
When marking calculations, substitution into an incorrect equation is not credited and
hence subsequent calculations within that section will score zero.
6.
Alternative answers are accepted even if not noted on the marking scheme as long
as they are appropriate, correct and valid in the context of the science. Note that in
some cases specific terms are a requirement. Any uncertainty about the
acceptability of an answer is clarified by consultation with the Principal Examiner or
Team Leader.
7.
Marking Quality of Written Communication: The marking scheme for these questions
includes indicative content which gives the outline of the content of a good answer.
Candidates should generally cover most, if not quite all, of the points in the indicative
content to achieve the highest mark band on these questions and if candidates
present alternative valid approaches these are equally acceptable. The tests to be
applied are coherence, which is expressed well scientifically, as well as
completeness and correct science at an appropriate level.
8.
Abbreviations used in mark schemes.
/
=
alternatives
not
=
unacceptable answer(s)
accept
=
not an ideal answer but just accepted on this occasion
(…..)
=
further material that would be required for a full answer but is not
required on this occasion
GCSE in CHEMISTRY Specimen Assessment Materials 44
Chemistry 1 Marking Scheme
Foundation Tier
Question
1.
(a)
Details
(i)
A
(ii)
I
Marks
1
1
II
ignore atom sizes but shading must be
unambiguous
atoms should touch but penalise once
only if small gaps between them
(b)
(i)
1
1
(ii)
6
1
Total marks for question
2.
(i)
I
II
carbon dioxide and oxygen – both needed
carbon dioxide
(ii)
similar patterns of fossils
shapes of continents
Total marks for question
3.
1
(i)
(ii)
(iii)
(iv)
to ensure that all the acid reacts / is neutralised /
pH changes / rises to 7
do not allow ‘to make alkaline’ or
reference to a pH higher than 7
I filtering
II evaporating
I
II
salt
elements are made of only one type of atom /
compounds are made of more than one type of atom
(one implied by the other)
sodium sulfate
allow correct formula
Total marks for question
5
1
1
2
4
1
1
1
1
1
1
6
GCSE in CHEMISTRY Specimen Assessment Materials 45
Question
4.
Details
Marks
(i)
34 (%)
1
(ii)
kills trees
poisons fish in lakes (or rivers)
damages buildings/metal structures’
any 2 for (1) each
2
(iii)
I
increase in number of cars on the road
accept reference to increase in any
of sources from pie chart
amount of nitrogen oxides released into the
atmosphere has reduced since catalytic converters
were introduced / upward trend in amount of nitrogen
oxides released has been reversed since catalytic
converters were introduced (1)
even though the number of cars on the road continues
to increase
(1)
II
Total marks for question
5.
(a)
(b)
(i)
I
II
(ii)
measurements taken at exactly the correct time /
measurements will be precise
there will be no random errors / measurements will be more
accurate than those made with a standard thermometer
results can be plotted as the reaction occurs
(i)
(ii)
30 – no tolerance
45 (°C) – no tolerance
2
6
1
1
1
bubbles form / gas is produced (1)
magnesium disappears (1)
2
green
1
Total marks for question
6.
1
(i)
nano-sized particles have different properties (from the bulk
material)
(ii)
any reasonable benefits to individual / community e.g.
generate electricity renewably /
without producing greenhouse emissions / wasting fossil fuels
in remote areas / in developing world
cheap electricity needs reference to initial cost of cells
up to (2) for two benefits or
one with good level of detail
any reasonable discussion of risk v benefit to support opinion
e.g. materials tested before use – no harm in short term and
millions of people could have access to electricity /
potentially dangerous waste material after useful life of solar
cells makes it too risky
(1)
Total marks for question
6
1
3
4
GCSE in CHEMISTRY Specimen Assessment Materials 46
Question
7.
(a)
(b)
Details
(i)
aluminium
iron
copper
Marks
(1) for aluminium first
2
(ii)
a substance loses oxygen / gains electrons
1
(i)
zinc sulfate
1
(ii)
copper
1
Total marks for question
8.
(a)
(i)
good electrical conductor
1
(ii)
90-110 with reference to m.p. being less than half way
between m.p. of potassium and m.p. of lithium (2)
64-89 or 111-179 with reference to higher than m.p. potassium
and lower m.p. than lithium (1)
2
2NaF – i.e. number of F atoms balanced (1)
all atoms balanced (1)
2
implication that evidence is strong when similar results are
observed for large numbers/ significant majority of people
results could be purely chance if only small numbers of people
complete survey
- any one
1
no bias e.g. would not gain or lose anything depending on the
result of the survey
1
high concentration/large amount of fluoride toxic/can cause
fluorosis/bone cancer
unethical to force all to take fluoride / mass medication
people can choose to use a fluoride toothpaste
- any one
1
(b)
(c)
5
(i)
(ii)
(iii)
Total marks for question
8
GCSE in CHEMISTRY Specimen Assessment Materials 47
Question
9.
Details
(i)
(ii)
(iii)
(iv)
(v)
Marks
volume / amount of water in flask
distance between burner and flask
do not accept ‘heating time’ / ‘initial water
temperature’ or reference to burner or flask
19
1
appropriate scale on y-axis e.g. 2 cm = 4 °C or 5 °C (1)
– no credit for 2 cm = 10 °C
all points plotted correctly ±½ square (1)
curve (or line) of best fit attempted (1)
3
temperature increase goes up as number of carbon atoms
increases
1
24 ± 2 small squares
mark consequentially from curve/line
accept only ‘24’ if no extrapolation
(vi)
(vii)
1
1
repeat the measurement for each fuel to see if similar results
are obtained
1
heat (from the flame) is lost to surroundings (1)
barrier to prevent draughts blowing flame /
shorten distance between flame and flask /
insulating material around flask (1)
2
Total marks for question
10
GCSE in CHEMISTRY Specimen Assessment Materials 48
Question
Details
Marks
10.
Indicative content: Reference to useful properties of plastics
e.g. resistance to corrosion, insulating properties, and to those
properties which are not desirable in this case e.g. flexibility,
low density. Reference to the fact that most waste plastic is
currently disposed of in landfill sites or burnt/incinerated and
the associated drawbacks. Reference to benefits of using
waste plastic e.g. reduced amounts disposed of in landfill
sites, reserves of other resources e.g. timber and sand, are
depleted less quickly / available for other uses.
6
5 – 6 marks
The candidate constructs an articulate, integrated
account correctly linking relevant points, such as
those in the indicative content, which shows
sequential reasoning. The answer fully addresses
the question with no irrelevant inclusions or
significant omissions. The candidate uses
appropriate scientific terminology and accurate
spelling, punctuation and grammar.
3 – 4 marks
The candidate constructs an account correctly
linking some relevant points, such as those in the
indicative content, showing some reasoning. The
answer addresses the question with some
omissions. The candidate uses mainly
appropriate scientific terminology and some
accurate spelling, punctuation and grammar.
1 – 2 marks
The candidate makes some relevant points, such
as those in the indicative content, showing limited
reasoning. The answer addresses the question
with significant omissions. The candidate uses
limited scientific terminology and inaccuracies in
spelling, punctuation and grammar.
0 marks
The candidate does not make any attempt or
give a relevant answer worthy of credit.
Total marks for question
6
GCSE in CHEMISTRY Specimen Assessment Materials 49
Chemistry 1 Marking Scheme
Higher Tier
Question
1.
(a)
Details
(i)
good electrical conductor
1
(ii)
90-110 with reference to m.p. being less than half way
between m.p. of potassium and m.p. of lithium (2)
64-89 or 111-179 with reference to higher than m.p. potassium
and lower m.p. than lithium (1)
2
2NaF – i.e. number of F atoms balanced (1)
all atoms balanced (1)
2
implication that evidence is strong when similar results are
observed for large numbers/ significant majority of people
results could be purely chance if only small numbers of people
complete survey
- any one
1
no bias e.g. would not gain or lose anything depending on the
result of the survey
1
high concentration/large amount of fluoride toxic/can cause
fluorosis/bone cancer
unethical to force all to take fluoride / mass medication
people can choose to use a fluoride toothpaste
- any one
1
(b)
(c)
Marks
(i)
(ii)
(iii)
Total marks for question
8
GCSE in CHEMISTRY Specimen Assessment Materials 50
Question
2.
Details
(i)
Marks
volume / amount of water in flask
distance between burner and flask
do not accept ‘heating time’ / ‘initial water
temperature’ or reference to burner or flask
1
(ii)
19
1
(iii)
appropriate scale on y-axis e.g. 2 cm = 4 °C or 5 °C (1)
– no credit for 2 cm = 10 °C
all points plotted correctly ±½ square (1)
curve (or line) of best fit attempted (1)
3
temperature increase goes up as number of carbon atoms
increases
1
(iv)
(v)
24 ± 2 small squares
mark consequentially from curve/line
accept only ‘24’ if no extrapolation
(vi)
(vii)
1
repeat the measurement for each fuel to see if similar results
are obtained
1
heat (from the flame) is lost to surroundings (1)
barrier to prevent draughts blowing flame /
shorten distance between flame and flask /
insulating material around flask (1)
2
Total marks for question
10
GCSE in CHEMISTRY Specimen Assessment Materials 51
Question
Details
Marks
3.
Indicative content: Reference to useful properties of plastics
e.g. resistance to corrosion, insulating properties, and to those
properties which are not desirable in this case e.g. flexibility,
low density. Reference to the fact that most waste plastic is
currently disposed of in landfill sites or burnt/incinerated and
the associated drawbacks. Reference to benefits of using
waste plastic e.g. reduced amounts disposed of in landfill
sites, reserves of other resources e.g. timber and sand, are
depleted less quickly / available for other uses.
6
5 – 6 marks
The candidate constructs an articulate, integrated
account correctly linking relevant points, such as
those in the indicative content, which shows
sequential reasoning. The answer fully addresses
the question with no irrelevant inclusions or
significant omissions. The candidate uses
appropriate scientific terminology and accurate
spelling, punctuation and grammar.
3 – 4 marks
The candidate constructs an account correctly
linking some relevant points, such as those in the
indicative content, showing some reasoning. The
answer addresses the question with some
omissions. The candidate uses mainly
appropriate scientific terminology and some
accurate spelling, punctuation and grammar.
1 – 2 marks
The candidate makes some relevant points, such
as those in the indicative content, showing limited
reasoning. The answer addresses the question
with significant omissions. The candidate uses
limited scientific terminology and inaccuracies in
spelling, punctuation and grammar.
0 marks
The candidate does not make any attempt or
give a relevant answer worthy of credit.
Total marks for question
6
GCSE in CHEMISTRY Specimen Assessment Materials 52
Question
4.
Details
(i)
(ii)
(iii)
Marks
small increase before 1900 (1)
much greater increase after 1900 (1)
2
large / great increase in amounts of fossil fuels burnt
do not accept ‘increase in numbers of cars’
(more) deforestation
1
I
II
1
1
(mean) temperature of Earth’s atmosphere is increasing
global warming
do not accept ‘greenhouse effect’
III melting of polar ice caps / climate change /
increased incidence of extreme weather events
Total marks for question
5.
(a)
(b)
zinc
1
(ii)
hydrogen
1
(iii)
sodium chloride (solution)
1
(iv)
copper(II) oxide
(i)
add powder / mix until fizzing stops / reaction is complete
(1)
filter unreacted / excess solid / powder
(1)
evaporate water (to give crystals)
(1)
accept ‘copper oxide’
CuCl2
Total marks for question
(a)
(i)
(ii)
(iii)
(iv)
1
3
1
8
aluminium oxide
accept ‘molten aluminium oxide’
ignore references to cryolite
do not accept ‘bauxite’
1
a substance loses oxygen
accept ‘substance gains electrons’
1
recycling used aluminium
locating smelting plant near a source of cheap electricity e.g. a
hydroelectric power station
1
overhead power cables
do not accept ‘electrical wires’
(b)
6
(i)
(ii)
6.
1
1
(i)
value of copper metal is higher than the face value of coins
1
(ii)
huge growth in manufacture of electrical / electronic goods
(which use copper wire)
accept reference to named goods
1
Total marks for question
6
GCSE in CHEMISTRY Specimen Assessment Materials 53
Question
7.
(a)
Details
(i)
(ii)
(b)
Marks
the greater the number of carbon atoms, the higher its boiling
point range
1
A
lights easily / burns with a clean flame
1
heat in the presence of catalyst – both needed (1)
produces reactive molecules / monomers used to make
plastics / produces more of lighter / more useful fractions (1)
2
Total marks for question
8.
4
show that magnesium displaces metal X from solution of its
nitrate (1)
show that metal X displaces iron from solution of iron nitrate (1)
accept converse logic
metal displaces less reactive metal from solution of its nitrate /
salts (1)
the fourth mark should only be awarded if the candidate
coherently links the conclusion to the point above
therefore X must be less reactive than magnesium but more
reactive than iron (1)
Total marks for question
4
4
GCSE in CHEMISTRY Specimen Assessment Materials 54
Question
Details
9.
each water molecule made of two hydrogen atoms and one
oxygen atom
1
lighted splint / flame
‘squeaky pop’ / small explosion - both needed
1
Indicative content: Description / explanation of advantages
and disadvantages of hydrogen gas as fuel for cars, based on
the table which appears in the question e.g. forms water
vapour on burning so does not contribute to global warming,
electricity required to produce hydrogen must be generated
somehow.
6
(a)
(b)
(c)
Marks
A complete response will include explanation of at least two
advantages and two disadvantages.
5 – 6 marks
The candidate constructs an articulate, integrated
account correctly linking relevant points, such as
those in the indicative content, which shows
sequential reasoning. The answer fully addresses
the question with no irrelevant inclusions or
significant omissions. The candidate uses
appropriate scientific terminology and accurate
spelling, punctuation and grammar.
3 – 4 marks
The candidate constructs an account correctly
linking some relevant points, such as those in the
indicative content, showing some reasoning. The
answer addresses the question with some
omissions. The candidate uses mainly appropriate
scientific terminology and some accurate spelling,
punctuation and grammar.
1 – 2 marks
The candidate makes some relevant points, such
as those in the indicative content, showing limited
reasoning. The answer addresses the question
with significant omissions. The candidate uses
limited scientific terminology and inaccuracies in
spelling, punctuation and grammar.
0 marks
The candidate does not make any attempt or
give a relevant answer worthy of credit.
Total marks for question
8
GCSE in CHEMISTRY Specimen Assessment Materials 55
ASSESSMENT GRIDS
GCSE in CHEMISTRY Specimen Assessment Materials 57
MARK SPECIFICATION GRID
Chemistry 1
Specimen unit examination
FOUNDATION TIER
Assessment Objective
C1 – The Earth and its
resources
Question
Number
1. (a)
1. (b)
2.
3. (i)(iv)
3. (ii)(iii)
Target Totals
for Paper
Specification
Reference
2. (c)(d)
7. (c)(g)
5. (e)(f)
AO1
AO2
AO3
24
21
15
1
2
4. (ii)
4
4
2
7. (i)
2
1
1
5. (a)(b)
3. (o)(p)
9. (i)(ii)(iii)
9. (iv)(v)(vi)(vii)
10.
6
9
1
1
2
4
9
2
3. (c)(d)
1
5
2
8. (a)
8. (c)
9
3
7. (b)
8. (b)
6
1
7. (a)(i)
7. (a)(ii)
9
3
5. (b)
6. (ii)
QWC
1
5. (a)(i)
6. (i)
HSW
6
4
4. (iii)
5. (a)(ii)
60
5
2
4. (i)
Total
Mark
1
1. (e)(g)
4. (h)
2
2
1
1
5
6. (f)(g)(h)
4
2
Raw Totals:
24
20
9
10
9
1
5
6. (d)
8
6
16
60
9
GCSE in CHEMISTRY Specimen Assessment Materials 58
MARK SPECIFICATION GRID
Chemistry 1
Specimen unit examination
HIGHER TIER
Assessment Objective
C1 – The Earth and its
resources
Question
Number
1. (a)
1. (b)
1. (c)
2. (i)(ii)(iii)
2. (iv)(v)(vi)(vii)
3.
4. (i)(ii)
4. (iii)
Target Totals
for Paper
Specification
Reference
1. (e)(g)
4. (h)
6. (f)(g)(h)
7. (h)(i)
5. (b)
5. (b)(c)(e)
7. (a)
7. (b)
8.
AO3
24
21
15
1
3. (d)(h)(k)(l)
6. (c)(d)
3. (c)
2
3
4
9
10
9
QWC
9
6
9
8
1
4
1
1
1
1
2
1
2
1
8
6
3
3
HSW
1
5
9. (a)
9. (b)
1
5
4
60
2
2
6. (d)
2. (f)
6. (b)
AO2
1
5. (a)
6. (a)
AO1
Total
Mark
6
9
4
9
4
1
4. (b)(c)(e)
9. (c)
Raw Totals:
1
8
4
2
24
22
14
60
9
9
GCSE in CHEMISTRY Specimen Assessment Materials 59
Candidate Name
Centre Number
Candidate Number
0
GCSE
CHEMISTRY
FOUNDATION TIER (Grades G-C)
CHEMISTRY 2 – Atoms, bonding and chemical change
SPECIMEN PAPER
(1 hour)
INSTRUCTIONS TO CANDIDATES
Write your name, centre number and candidate number in the spaces at the top of this
page.
Answer all questions.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded that assessment will take into account the quality of written
communication used in your answer to question 8(a).
GCSE in CHEMISTRY Specimen Assessment Materials 60
Answer all questions.
1.
(a)
Soap solution was shaken with four different water samples.
The results are shown in the diagram below.
(i)
Complete the bar chart of the results on the grid below.
[2]
GCSE in CHEMISTRY Specimen Assessment Materials 61
(ii)
(iii)
Complete the following sentences.
I
The hardest water is in sample ........................................... [1]
II
The softest water is in sample ............................................ [1]
I
Using the information in the diagram opposite, state one
factor which was controlled in order to make the investigation a
fair test.
[1]
.............................................................................................
II
State one other factor which you would choose to keep
constant if you were planning to repeat the investigation.
[1]
.............................................................................................
(b)
(i)
Choose, from the box below, the metal ions that cause hardness when
present in water.
[1]
calcium
iron
sodium
..............................................................................
(ii)
State one advantage of hard water.
.....................................................................................................................
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 62
2.
(a)
The diagram below shows an atom of lithium.
(i)
Use the numbers in the box below to answer parts (i) I and II.
1
2
3
4
7
Give the
(ii)
I
atomic number of lithium, ................................................
[1]
II
mass number of lithium. ..................................................
[1]
Complete the following sentences.
I
II
(b)
Protons and ...................................... are always found in
equal numbers in atoms.
[1]
Protons and ....................................... have equal masses.
[1]
Calculate the relative molecular mass (Mr) of ammonia, NH3.
Ar(N) = 14
[2]
Ar(H) = 1
.........................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 63
3.
(a)
Substances can be classified as
y
y
y
y
metallic
ionic
simple molecular
giant covalent
Use the types of substance named above to complete the following
sentences.
(i)
Carbon dioxide is a gas at room temperature due to it being
......................................................................................................
(ii)
Sodium chloride conducts electricity when in solution due to it being
.......................................................................................................
(b)
[1]
[1]
The following diagram shows the structure of a metal.
(i)
Using the diagram, complete the following sentence to explain why
metals are good conductors of electricity.
[2]
When a metal is connected to a battery .................................... move
across the structure towards the ............................................................
(ii)
State one property of a metal that can be explained by the fact that
the positive ions can slide over each other.
[1]
..............................................................................................................
(c)
The following diagrams, A, B and C, show the structures of methane, graphite
and diamond but not necessarily in that order.
[2]
Label each diagram with the correct name.
A ........................
B ........................
C ........................
GCSE in CHEMISTRY Specimen Assessment Materials 64
4.
(i)
The box below shows some smart materials.
thermochromic materials
photochromic materials
hydrogels
shape memory alloys
shape memory polymers
Choose from the box the type of smart materials that
I
are used to make lenses for sunglasses,
[1]
…………………………………………………………………………………….
II
swell up to 1000 times in volume when added to water.
[1]
…………………………………………………………………………………….
(ii)
Nitinol and steel are both alloys. Nitinol is a shape memory alloy but steel is
not.
Sian made coils from straight lengths of nitinol and steel wires and gave both
to Kieran.
Describe what Kieran should do to find out which is which, stating the
observations for both wires.
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
[2]
GCSE in CHEMISTRY Specimen Assessment Materials 65
5.
This question is about the reactions of potassium.
(i)
State why potassium is stored in bottles of paraffin oil.
[1]
.........................................................................................................
(ii)
I
Complete the following risk assessment which the teacher
carried out before demonstrating the reaction of potassium
with water.
[2]
Hazard
Precaution
handle with tongs
molten potassium splatters
and lands on student's skin
II
The following diagram shows what happens when potassium
reacts with water.
flame
gas G
potassium
water
Name gas G. ....................................................................... [1]
(iii)
Complete and balance the symbol equation for the reaction
of potassium and chlorine to form potassium chloride.
2K
+
Cl2
..............
[2]
GCSE in CHEMISTRY Specimen Assessment Materials 66
6.
(a)
Ravinder is given three solutions, labelled A, B and C. He carries out tests to
identify the compound present in each. The results of the tests are shown
below.
Test
Solution
Flame test
Addition of silver nitrate
A
crimson flame
cream precipitate
B
orange-yellow flame
white precipitate
C
lilac flame
yellow precipitate
Use these results to identify the compound present in each solution.
(b)
A
.............................................................
B
.............................................................
C
.............................................................
[3]
Jo found that each of her solutions gave a yellow precipitate when silver
nitrate was added.
Suggest how this may have happened and any possible steps that could be
taken to ensure that the same did not occur on repeating the tests.
[2]
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
GCSE in CHEMISTRY Specimen Assessment Materials 67
7.
The graph below shows the solubility of potassium nitrate in water at different
temperatures.
(i)
The table below shows the solubility of potassium bromide in water at
different temperatures. The solubility at 60 °C is missing from the table.
Temperature
/ ºC
0
10
20
30
40
50
Solubility
/ g per 100 g water
54
58
64
70
76
82
60
70
80
92
98
GCSE in CHEMISTRY Specimen Assessment Materials 68
I
II
Draw the graph of the solubility of potassium bromide on the grid
overleaf. Two points have been plotted for you.
[2]
Use the graph to give the solubility of potassium bromide at 60 °C.
[1]
…………………….. g per 100 g water
III
Give the temperature at which the two compounds have the same
solubility.
[1]
……………………. °C
IV
Describe the trend in the solubility of potassium bromide and how it
differs from that of potassium nitrate.
[2]
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
(ii)
I
Emmanuel tested the solubility of a lithium compound in water at a
range of temperatures from 20 to 60 °C.
Temperature
/ °C
Solubility
/ g per 100 g water
20
30
40
50
60
34.8
34.2
33.7
33.2
32.6
He was surprised to see that the solubility appeared to decrease as
the temperature of the water increased.
Suggest what he should do before reporting his results to his teacher.
[1]
……………………………………………………………………………….
II
Give a reason why Emmanuel decided to measure and record the
solubility of this compound to the nearest 0.1 g per 100 g water.
[1]
…………………………………………………………………………………….
…………………………………………………………………………………….
GCSE in CHEMISTRY Specimen Assessment Materials 69
8.
(a)
A chlorine atom contains 17 negatively charged electrons in orbit around its
nucleus as shown in the following diagram.
Explain why a chlorine atom has no overall charge and describe the link
between its electronic structure and its position in the Periodic Table.
[6 QWC]
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
(b)
Chlorine has two isotopes – chlorine-35 and chlorine-37.
State what is meant by the term isotopes.
…………………………………………………………………………………….
…………………………………………………………………………………….
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 70
9.
Jan and Gareth investigated how the temperature of hydrochloric acid affected the
rate of its reaction with marble chips.
They added identical amounts of marble chips to samples of acids with different
temperatures and measured the time taken to collect 50 cm3 of carbon dioxide gas.
(a)
Their results are shown in the following table.
Time taken to collect 50 cm3 of gas / seconds
Temperature
of acid / °C
20
1
2
3
75
68
71
30
48
49
47
40
50
32
34
50
19
17
15
60
8
10
9
(i)
Mean
Each experiment was performed 3 times in order to find out whether
or not the results are ‘repeatable’. Identify one result from the table
which should be checked e.g. by repeating the experiment once more.
[1]
…………………………………………………………………………….
(ii)
Suggest one possible explanation for this particular reading.
…………………………………………………………………………….
…………………………………………………………………………….
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 71
(iii)
Calculate the mean values for the time taken to collect 50 cm3 of gas
at each different temperature.
[2]
…………………………………………………………………………….
…………………………………………………………………………….
…………………………………………………………………………….
(b)
State the conclusion that Jan and Gareth should draw from the evidence they
have collected.
[1]
…………………………………………………………………………………….
…………………………………………………………………………………….
(c)
Another pair of students chose to investigate the effect of acid concentration
on the rate of reaction.
(i)
They were given acid of concentration 2.0 M to be diluted to prepare
solutions of lower concentrations. Suggest suitable acid
concentrations for them to use in their investigation.
[2]
………………………………………………………………………….
………………………………………………………………………….
………………………………………………………………………….
(ii)
They found that the reaction proceeded more quickly as the
concentration increased. Explain why this is the case using particle
theory.
[2]
………………………………………………………………………….
………………………………………………………………………….
………………………………………………………………………….
GCSE in CHEMISTRY Specimen Assessment Materials 72
FORMULAE FOR SOME COMMON IONS
POSITIVE IONS
NEGATIVE IONS
NAME
FORMULA
NAME
FORMULA
Aluminium
Al3+
Bromide
Br-
Ammonium
NH4+
Carbonate
CO32-
Barium
Ba2+
Chloride
CI-
Calcium
Ca2+
Fluoride
F-
Copper(II)
Cu2+
Hydroxide
OH-
Hydrogen
H+
Iodide
I-
Iron(II)
Fe2+
Nitrate
NO3-
Iron(III)
Fe3+
Oxide
O2-
Lithium
Li+
Sulfate
SO42-
Magnesium
Mg2+
Nickel
Ni2+
Potassium
K+
Silver
Ag+
Sodium
Na+
GCSE in CHEMISTRY Specimen Assessment Materials 73
GCSE in CHEMISTRY Specimen Assessment Materials 75
Candidate Name
Centre Number
Candidate Number
0
GCSE
CHEMISTRY
HIGHER TIER (Grades D-A*)
CHEMISTRY 2 – Atoms, bonding and chemical change
SPECIMEN PAPER
(1 hour)
INSTRUCTIONS TO CANDIDATES
Write your name, centre number and candidate number in the spaces at the top of this
page.
Answer all questions.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded that assessment will take into account the quality of written
communication used in your answer to questions 2(a) and 8(a).
GCSE in CHEMISTRY Specimen Assessment Materials 76
1.
The graph below shows the solubility of potassium nitrate in water at different
temperatures.
(i)
The table below shows the solubility of potassium bromide in water at
different temperatures. The solubility at 60 °C is missing from the table.
Temperature
/ ºC
0
10
20
30
40
50
Solubility
/ g per 100 g water
54
58
64
70
76
82
60
70
80
92
98
GCSE in CHEMISTRY Specimen Assessment Materials 77
I
II
Draw the graph of the solubility of potassium bromide on the grid
opposite. Two points have been plotted for you.
[2]
Use the graph to give the solubility of potassium bromide at 60 °C.
[1]
…………………….. g per 100 g water
III
Give the temperature at which the two compounds have the same
solubility.
[1]
……………………. °C
IV
Describe the trend in the solubility of potassium bromide and how it
differs from that of potassium nitrate.
[2]
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
(ii)
I
Emmanuel tested the solubility of a lithium compound in water at a
range of temperatures from 20 to 60 °C.
Temperature
/ °C
Solubility
/ g per 100 g water
20
30
40
50
60
34.8
34.2
33.7
33.2
32.6
He was surprised to see that the solubility appeared to decrease as
the temperature of the water increased.
Suggest what he should do before reporting his results to his teacher.
[1]
……………………………………………………………………………….
II
Give a reason why Emmanuel decided to measure and record the
solubility of this compound to the nearest 0.1 g per 100 g water.
[1]
…………………………………………………………………………………….
…………………………………………………………………………………….
GCSE in CHEMISTRY Specimen Assessment Materials 78
2.
(a)
A chlorine atom contains 17 negatively charged electrons in orbit around its
nucleus as shown in the following diagram.
Explain why a chlorine atom has no overall charge and describe the link
between its electronic structure and its position in the Periodic Table.
[6 QWC]
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
(b)
Chlorine has two isotopes – chlorine-35 and chlorine-37.
State what is meant by the term isotopes.
…………………………………………………………………………………….
…………………………………………………………………………………….
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 79
3.
Jan and Gareth investigated how the temperature of hydrochloric acid affected the
rate of its reaction with marble chips.
They added identical amounts of marble chips to samples of acids with different
temperatures and measured the time taken to collect 50 cm3 of carbon dioxide gas.
(a)
Their results are shown in the following table.
Time taken to collect 50 cm3 of gas / seconds
Temperature
of acid / °C
20
1
2
3
75
68
71
30
48
49
47
40
50
32
34
50
19
17
15
60
8
10
9
(i)
Mean
Each experiment was performed 3 times in order to find out whether
or not the results are ‘repeatable’. Identify one result from the table
which should be checked e.g. by repeating the experiment once more.
[1]
…………………………………………………………………………….
(ii)
Suggest one possible explanation for this particular reading.
…………………………………………………………………………….
…………………………………………………………………………….
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 80
(iii)
Calculate the mean values for the time taken to collect 50 cm3 of gas
at each different temperature.
[2]
…………………………………………………………………………….
…………………………………………………………………………….
…………………………………………………………………………….
(b)
State the conclusion that Jan and Gareth should draw from the evidence they
have collected.
[1]
…………………………………………………………………………………….
…………………………………………………………………………………….
(c)
Another pair of students chose to investigate the effect of acid concentration
on the rate of reaction.
(i)
They were given acid of concentration 2.0 M to be diluted to prepare
solutions of lower concentrations. Suggest suitable acid
concentrations for them to use in their investigation.
[2]
………………………………………………………………………….
………………………………………………………………………….
………………………………………………………………………….
(ii)
They found that the reaction proceeded more quickly as the
concentration increased. Explain why this is the case using particle
theory.
[2]
………………………………………………………………………….
………………………………………………………………………….
………………………………………………………………………….
GCSE in CHEMISTRY Specimen Assessment Materials 81
4.
(a)
A forensic scientist has recovered an ink sample from the scene of a crime
and wants to compare it with samples found in the possession of three
suspects.
She finds that the recovered ink has an Rf value of 0.7.
Use the information in the following chromatogram and the formula given to
discover which, if any, of the inks match that from the crime scene. You must
show your working.
[2]
R f value =
distance travelled by the ink
distance travelled by the solvent
6
solvent front
5
4
3
2
1
0 cm
A
B
C
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
(b)
(i)
Simple compounds containing potassium can be identified using a
flame test.
State the flame colour seen when potassium chloride is heated in a
blue flame.
[1]
…………….......………………………………………………………………
(ii)
Name a technique that could be used to identify and measure the
amount of potassium present in biological tissue.
[1]
…………….......………………………………………………………………
GCSE in CHEMISTRY Specimen Assessment Materials 82
5.
(a)
Magnesium reacts with oxygen to form magnesium oxide.
(i)
Using the electronic structures given below, show by means of a
diagram the electronic changes that take place during the formation of
magnesium oxide. Show the charges on the ions formed.
[3]
magnesium = 2,8,2
(ii)
oxygen = 2,6
State why magnesium oxide is a high melting point solid.
[1]
..............................................................................................................
.
(b)
..............................................................................................................
The diagram below shows the type of bonding present in methane, CH4.
(i)
Name this type of bonding. ............................................................ [1]
(ii)
The bonds within the molecule are very strong. Despite this, methane
has a low boiling point. State why this is the case.
[1]
..............................................................................................................
..............................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 83
(c)
The structures of diamond and graphite are shown below.
Give the reason why
(i)
diamond is hard,
[1]
................................................................................................................
................................................................................................................
(ii)
graphite can be used as a lubricant.
[1]
................................................................................................................
................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 84
6.
This question is about the halogens and the halides – the elements of Group 7 and
their compounds.
(a)
When bromine water is added to a solution of sodium iodide, a brown solution
is formed showing that a reaction has occurred. No reaction occurs when
bromine water is added to a solution of sodium chloride.
(i)
Explain this difference in terms of the relative reactivities of the
halogens.
[1]
................................................................................................................
................................................................................................................
(ii)
Balance the following chemical equation for the reaction that takes
place between bromine water and sodium iodide.
[1]
Br2
(b)
+
NaI
→
NaBr
+
I2
Sodium bromide and sodium iodide can also be distinguished from one
another by their reaction with silver nitrate solution.
Give the expected observation for one of the reactions, stating clearly to
which one it refers.
[1]
............................................................................................................................
(c)
Write an ionic equation for the reaction of silver ions and chloride ions.
[1]
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 85
7.
Steve and Justin carried out an investigation to find the relative hardness of four
water samples, A, B, C and D. They added soap solution to each sample, shook the
mixtures and recorded the time taken for the lather to disappear.
Their results are as follows.
Time for lather to disappear / seconds
Test 1
Test 2
A
310
300
B
400
410
C
30
30
D
90
100
(i)
State which water sample is the hardest and give a reason for your answer.
[1]
…………………………………………………………………………………….
(ii)
Three other groups carried out similar investigations and they recorded their
results in the same table.
Time for lather to disappear / seconds
Group 1
Group 2
Group 3
A
180
250
80
B
220
400
100
C
20
40
10
D
80
100
20
To what extent do these results confirm your conclusion in (i)?
Suggest a possible reason for the difference between each group’s results.
[2]
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
(iii)
State which ions, in addition to calcium ions, cause hardness in water.
…………………………………………………………………………………….
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 86
8.
(a)
Explain how crude oil is separated into different fractions.
[6 QWC]
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
…………………………………………………………………………………….
(b)
When ethene, C2H4, burns in air, carbon dioxide and water are formed as
shown in the following equation.
C2H4
+
3O2
2CO2
+
2H2O
The relative amounts of energy needed to break the bonds in the reactants are
shown in the table below.
Bond
Amount of energy needed to break bond / kJ
C=C
612
C–H
413
O=O
496
GCSE in CHEMISTRY Specimen Assessment Materials 87
(i)
Use these values to calculate the relative energy (in kJ) needed to
break all the bonds in the reactants.
[2]
……………………………………………………………………………….
……………………………………………………………………………….
(ii)
4828 kJ of energy are released when new bonds are formed in the
products. Calculate the overall energy change for the reaction.
[1]
……………………………………………………………………………….
GCSE in CHEMISTRY Specimen Assessment Materials 88
9.
(a)
Smart materials have unusual properties. Describe the unusual property that
(i)
smart alloys show on heating,
[1]
..........................................................................................................
(ii)
thermochromic materials show on heating.
[1]
..........................................................................................................
(b)
The most effective and widely used smart alloy is nitinol which contains 50 %
titanium.
Titanium, Ti, is a metal which is extracted from ores containing titanium(IV)
oxide. This oxide is converted into titanium(IV) chloride, TiCI4, which is then
reacted with either sodium or magnesium to form titanium metal. The equation
below shows the formation of titanium from titanium chloride using sodium.
TiCI4
(i)
+
4Na
Ti
Ar(Na) = 23
Ar(Ti) = 48
+
4NaCI
Use the equation above to calculate how many tonnes of sodium would
be needed to produce 96 tonnes of titanium.
[3]
..................................................................................................................
..................................................................................................................
..................................................................................................................
(ii)
Titanium forms another chloride in which 48 g of titanium is combined
with 71 g of chlorine. Calculate the simplest formula for this chloride of
titanium. Show your working.
[2]
Ar(CI) = 35.5
Ar(Ti) = 48
..................................................................................................................
..................................................................................................................
..................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 89
FORMULAE FOR SOME COMMON IONS
POSITIVE IONS
NEGATIVE IONS
NAME
FORMULA
NAME
FORMULA
Aluminium
Al3+
Bromide
Br-
Ammonium
NH4+
Carbonate
CO32-
Barium
Ba2+
Chloride
CI-
Calcium
Ca2+
Fluoride
F-
Copper(II)
Cu2+
Hydroxide
OH-
Hydrogen
H+
Iodide
I-
Iron(II)
Fe2+
Nitrate
NO3-
Iron(III)
Fe3+
Oxide
O2-
Lithium
Li+
Sulfate
SO42-
Magnesium
Mg2+
Nickel
Ni2+
Potassium
K+
Silver
Ag+
Sodium
Na+
GCSE in CHEMISTRY Specimen Assessment Materials 90
GCSE in CHEMISTRY Specimen Assessment Materials 91
MARK SCHEMES
GCSE in CHEMISTRY Specimen Assessment Materials 93
General Marking Instructions
1.
Over-rigidity in the interpretation of the mark scheme is not intended and it is
accepted that points may be made in a variety of different ways including converse
and counterpoints.
2.
Phonetic spelling is allowed except where there is a possibility that scientific terms
might be confused.
3.
When candidates list alternative answers to short answer questions, the general
principle to be followed is: right + wrong = no mark. In a question requiring a set
number of responses, where a candidate has supplied extra responses above the
required number each error/contradiction negates one correct response, however
responses considered neutral (ie not incorrect) are not penalised.
4.
The principle of error carried forward is generally applied where an incorrect value
calculated in one part of a question is treated as being correct for the purposes of
subsequent parts.
5.
When marking calculations, substitution into an incorrect equation is not credited and
hence subsequent calculations within that section will score zero.
6.
Alternative answers are accepted even if not noted on the marking scheme as long
as they are appropriate, correct and valid in the context of the science. Note that in
some cases specific terms are a requirement. Any uncertainty about the
acceptability of an answer is clarified by consultation with the Principal Examiner or
Team Leader.
7.
Marking Quality of Written Communication: The marking scheme for these questions
includes indicative content which gives the outline of the content of a good answer.
Candidates should generally cover most, if not quite all, of the points in the indicative
content to achieve the highest mark band on these questions and if candidates
present alternative valid approaches these are equally acceptable. The tests to be
applied are coherence, which is expressed well scientifically, as well as
completeness and correct science at an appropriate level.
8.
Abbreviations used in mark schemes.
/
=
alternatives
not
=
unacceptable answer(s)
accept
=
not an ideal answer but just accepted on this occasion
(…..)
=
further material that would be required for a full answer but is not
required on this occasion
GCSE in CHEMISTRY Specimen Assessment Materials 94
Chemistry 2 Marking Scheme
Foundation Tier
Question
1.
(a)
Details
Marks
(i) all bars plotted correctly (2)
two bars plotted correctly (1)
2
– tolerance ±½ small square
(ii) I
II
C
A
1
1
(iii) I
same volume / amount of water in each tube
1
same amount / mass / volume of soap
same type of soap used
same water temperature
– any one
1
II
(b)
(i) calcium
1
(ii) strengthens teeth / bones
reduces incidence of heart disease
tastes better / makes better beer
limescale coating inside metal pipes stops poisonous salts
dissolving in water
– any one
Total marks for question
2.
(a)
(b)
1
8
(i) I
II
3
7
1
1
(ii) I
II
electrons
neutrons
1
1
recognise the presence of 3 H atoms but only one N atom (1)
14 + 3 = 17 (1)
(2) for correct answer only
Total marks for question
2
6
GCSE in CHEMISTRY Specimen Assessment Materials 95
Question
3.
(a)
(b)
(c)
Details
Marks
(i) simple molecular
1
(ii) ionic
1
(i) (free) electrons (1)
positive (charge/terminal/end) - do not accept ‘positive ions’(1)
2
(ii) ductile / can be stretched into wires
malleable / can be beaten into shape
1
A – methane
B – diamond
C – graphite – all three correct for (2), one correct for (1)
2
Total marks for question
4.
(i) I
II
photochromic materials
hydrogels
1
1
(ii) place wires in hot water / water at 50 °C or hotter
(1)
nitinol wire regains original shape but steel is not affected (1)
Total marks for question
5.
(i) to prevent it from reacting with oxygen in the air
(ii) I
II
Hazard – burns skin on contact /
reacts with moisture on skin
(1)
Precaution – carry out reaction behind safety screen
do not accept ‘wear safety goggles’ (1)
hydrogen
(b)
A – lithium bromide
B – sodium chloride
C – potassium iodide
4
2
1
2
Total marks for question
(a)
2
1
(iii) KCl (1)
2 in box before formula (1) – formula must be correct
6.
7
(1)
(1)
(1)
6
3
tubes / pipettes contaminated with solution C /
potassium iodide
ensure tubes are washed before use /
clean pipette for each solution
(1)
(1)
Total marks for question
2
5
GCSE in CHEMISTRY Specimen Assessment Materials 96
Question
7.
Details
(i) I
Marks
all points plotted correctly (1) – tolerance ±½ square
– allow 1 error
straight line of best fit attempted (1)
2
87 ±1
48 ±1
higher the temperature, the higher the solubility
(1)
solubility of potassium bromide increases gradually as the
temperature rises but that of potassium nitrate increases
very quickly / roughly doubles for each 20 (ºC) rise
– or converse explanation
(1)
1
1
2
(ii) I
repeat experiment to see if similar results are obtained
1
II
values very close together / same values at two different
temperatures if measured to the nearest 1 (g per 100 g
water)
1
II
III
IV
Total marks for question
8
GCSE in CHEMISTRY Specimen Assessment Materials 97
Question
Details
8.
Indicative content: A chlorine atom contains 17 positively
charged protons which balance the charge associated with the
electrons. The number of electrons in an atom’s outermost
orbit is its group number and the number of occupied orbits is
its period number – Group 7 and Period 3 in the case of
chlorine.
(a)
(b)
Marks
5 – 6 marks
The candidate constructs an articulate, integrated
account correctly linking relevant points, such as
those in the indicative content, which shows
sequential reasoning. The answer fully addresses
the question with no irrelevant inclusions or
significant omissions. The candidate uses
appropriate scientific terminology and accurate
spelling, punctuation and grammar.
3 – 4 marks
The candidate constructs an account correctly
linking some relevant points, such as those in the
indicative content, showing some reasoning. The
answer addresses the question with some
omissions. The candidate uses mainly appropriate
scientific terminology and some accurate spelling,
punctuation and grammar.
1 – 2 marks
The candidate makes some relevant points, such
as those in the indicative content, showing limited
reasoning. The answer addresses the question
with significant omissions. The candidate uses
limited scientific terminology and inaccuracies in
spelling, punctuation and grammar.
0 marks
The candidate does not make any attempt or
give a relevant answer worthy of credit.
atoms of the same element with different numbers of neutrons
in the nucleus/atoms with the same number of protons but
different numbers of neutrons
accept chlorine-35 has 18 neutrons and chlorine-37 has 20
neutrons
Total marks for question
6
1
7
GCSE in CHEMISTRY Specimen Assessment Materials 98
Question
9.
(a)
Details
Marks
(i) 1st reading at 40 (ºC)
1
(ii) too slow putting connecting syringe / putting stopper on flask
gas escaping
acid heated to 30 (ºC) rather than 40 (ºC) / acid not heated
enough
larger marble chips used / marble chips had smaller surface
area
– any one
(iii) four correct means of three results i.e. 71, 48, 17 and
9 (seconds)
(1)
mean of two results for 40 ºC i.e. 33 (seconds)
(1)
(b)
(c)
the higher the temperature, the higher the rate of reaction / the
faster the reaction / the more quickly gas is produced
(i) sensible range e.g. 0.4 to 2.0 (M) or 1.0 to 2.0 (M) (1)
at least four different concentrations, equal intervals (1)
(ii) more particles present in solution of higher concentration (1)
the second mark should only be awarded if the candidate
coherently links greater collision rate to greater number of
particles present
collisions more likely / more collisions per second
(1)
Total marks for question
1
2
1
2
2
9
GCSE in CHEMISTRY Specimen Assessment Materials 99
Chemistry 2 Marking Scheme
Higher Tier
Question
1.
Details
(i) I
II
III
IV
(ii) I
II
Marks
all points plotted correctly (1) – tolerance ±½ square
– allow 1 error
straight line of best fit attempted (1)
2
87 ±1
48 ±1
higher the temperature, the higher the solubility
(1)
solubility of potassium bromide increases gradually as the
temperature rises but that of potassium nitrate increases
very quickly / roughly doubles for each 20 (ºC) rise
– or converse explanation
(1)
1
1
repeat experiment to see if similar results are obtained
values very close together / same values at two different
temperatures if measured to the nearest 1 (g per 100 g
water)
Total marks for question
2
1
1
8
GCSE in CHEMISTRY Specimen Assessment Materials 100
Question
Details
2.
Indicative content: A chlorine atom contains 17 positively
charged protons which balance the charge associated with the
electrons. The number of electrons in an atom’s outermost
orbit is its group number and the number of occupied orbits is
its period number – Group 7 and Period 3 in the case of
chlorine.
(a)
(b)
Marks
5 – 6 marks
The candidate constructs an articulate, integrated
account correctly linking relevant points, such as
those in the indicative content, which shows
sequential reasoning. The answer fully addresses
the question with no irrelevant inclusions or
significant omissions. The candidate uses
appropriate scientific terminology and accurate
spelling, punctuation and grammar.
3 – 4 marks
The candidate constructs an account correctly
linking some relevant points, such as those in the
indicative content, showing some reasoning. The
answer addresses the question with some
omissions. The candidate uses mainly appropriate
scientific terminology and some accurate spelling,
punctuation and grammar.
1 – 2 marks
The candidate makes some relevant points, such
as those in the indicative content, showing limited
reasoning. The answer addresses the question
with significant omissions. The candidate uses
limited scientific terminology and inaccuracies in
spelling, punctuation and grammar.
0 marks
The candidate does not make any attempt or
give a relevant answer worthy of credit.
6
atoms of the same element with different numbers of neutrons
in the nucleus/atoms with the same number of protons but
different numbers of neutrons
accept chlorine-35 has 18 neutrons and chlorine-37 has 20
neutrons
1
Total marks for question
7
GCSE in CHEMISTRY Specimen Assessment Materials 101
Question
3.
(a)
Details
Marks
(i) 1st reading at 40 (ºC)
1
(ii) too slow putting connecting syringe / putting stopper on flask
gas escaping
acid heated to 30 (ºC) rather than 40 (ºC)/acid not heated
enough
larger marble chips used/marble chips had smaller surface
area
– any one
(iii) four correct means of three results i.e. 71, 48, 17 and
9 (seconds)
(1)
mean of two results for 40 ºC i.e. 33 (seconds)
(1)
(b)
(c)
the higher the temperature, the higher the rate of reaction / the
faster the reaction / the more quickly gas is produced
(i) sensible range e.g. 0.4 to 2.0 (M) or 1.0 to 2.0 (M)
(1)
at least four different concentrations, equal intervals (1)
(ii) more particles present in solution of higher concentration (1)
the second mark should only be awarded if the candidate
coherently links greater collision rate to greater number of
particles present
collisions more likely / more collisions per second
(1)
Total marks for question
4.
(a)
(b)
Rf value for sample B calculated / distance travelled by
recovered ink calculated
- workings must be shown (1)
Specimen B has Rf value 0.7 / travelled 4.2 (cm) so is the ink
that matches the sample found at the crime scene (1)
(i) lilac
accept purple
1
2
1
2
2
9
2
1
(ii) atomic spectroscopy
1
Total marks for question
4
GCSE in CHEMISTRY Specimen Assessment Materials 102
Question
5.
(a)
(b)
(c)
6.
(a)
Details
Marks
(i) diagram clearly showing magnesium atom losing 2 electrons
(1)
diagram clearly showing oxygen atom gaining 2 electrons (1)
charges on both ions shown
(1)
3
(ii) strong attraction between ions of opposite charge /
requires large amount of (heat) energy to break bonds
1
(i) covalent
1
(ii) weak bonds between molecules
1
(i) strong (covalent) bonds between all atoms / in all directions
1
(ii) weak bonds between layers allow them to slide over one
another
Total marks for question
1
(i) bromine is more reactive than iodine but less reactive than
chlorine
1
8
(ii)
Br2
+
2 NaI
→
2 NaBr
+
I2
(b)
sodium bromide gives a cream precipitate or
sodium iodide gives a yellow precipitate
(c)
Ag+
+
Cl−
→
1
1
AgCl
Total marks for question
7.
1
4
(i) C is the hardest because its lather is the poorest /
lasts least time
1
(ii) results confirm the conclusion because C has the poorest
lather in each group
(1)
each group may have used different volumes of water / soap
solution / concentrations of soap solution
(1)
2
(iii) magnesium / Mg2+
1
Total marks for question
4
GCSE in CHEMISTRY Specimen Assessment Materials 103
Question
Details
8.
Indicative content: Crude oil is vaporised (by heating) and
pumped in at the bottom of a fractionating column. The
column is hottest at the bottom but even at high temperature
the heavier fractions (or those with longer hydrocarbon chains)
condense and can be collected. Lighter fractions (or those
with shorter chains) rise through the column and cool and
condense at their boiling temperatures, while the very lightest
fractions are collected as gases at the top of the column.
(a)
(b)
Marks
5 – 6 marks
The candidate constructs an articulate, integrated
account correctly linking relevant points, such as
those in the indicative content, which shows
sequential reasoning. The answer fully addresses
the question with no irrelevant inclusions or
significant omissions. The candidate uses
appropriate scientific terminology and accurate
spelling, punctuation and grammar.
3 – 4 marks
The candidate constructs an account correctly
linking some relevant points, such as those in the
indicative content, showing some reasoning. The
answer addresses the question with some
omissions. The candidate uses mainly appropriate
scientific terminology and some accurate spelling,
punctuation and grammar.
1 – 2 marks
The candidate makes some relevant points, such
as those in the indicative content, showing limited
reasoning. The answer addresses the question
with significant omissions. The candidate uses
limited scientific terminology and inaccuracies in
spelling, punctuation and grammar.
0 marks
The candidate does not make any attempt or
give a relevant answer worthy of credit.
6
(i) (4 ° 413) + 612 + (3 ° 496) (1)
3752 (kJ)
(1)
(2) for correct answer only
(ii) −1076 (kJ)
do not accept +1076
Total marks for question
2
1
9
GCSE in CHEMISTRY Specimen Assessment Materials 104
Question
9.
(a)
(b)
Details
Marks
(i) regain their original shape
1
(ii) (reversibly) change colour
1
(i) Substitution 4(23) : 1(48)
or 96/48 = 2 moles (1)
Ratio 8(23) : 2(48)
or 4 moles : 1 mole ∴ 8 : 2 (1)
3
184 (tonnes) (1)
(3) for correct answer only
(ii) Ratio
48/48 : 71/35.5 = 1:2 (1)
TiCl2 (1)
2
no mark for formula
unless working is shown
Total marks for question
7
GCSE in CHEMISTRY Specimen Assessment Materials 105
ASSESSMENT GRIDS
GCSE in CHEMISTRY Specimen Assessment Materials 107
MARK SPECIFICATION GRID
Chemistry 2
Specimen unit examination
FOUNDATION TIER
C2 – Atoms, bonding and
chemical change
Question
Number
1. (a)(i)
1. (a)(ii)
1. (a)(iii)
Target Totals
for Paper
Specification
Reference
Assessment Objective
AO1
AO2
AO3
24
24
12
2
7. (i), (j)
2
4. (ii)
1. (b), (d), (e),
(f)
6. (b)
7. (i)
7. (ii)
8.
3. (a), (b), (g)
3. (f)
7
9. (b)
9
7
2
2
4
2
6
9
1
2. (a), (b), (d)
1
2
3
2. (f), (g)
2
4
7. (h)
1. (d), (h), (i)
5
7
8
2
1
9. (c)
24
9
9
9
25
9
9
4
Raw Totals:
9
7
2
4. (a), (b)
9
9
2
2
9. (a)(i)(ii)
9. (a)(iii)
9
6
2
5. (iii)
6. (a)
8
2
5. (i)
5. (ii)
QWC
2
2. (b)
4. (i)
HSW
2
2. (a)(i)
3.
60
2
1. (b)
2. (a)(ii)
Total
Mark
11
60
GCSE in CHEMISTRY Specimen Assessment Materials 108
MARK SPECIFICATION GRID
Chemistry 2
Specimen unit examination
HIGHER TIER
C2 – Atoms, bonding and
chemical change
Question
Number
1. (i)
1. (ii)
2.
Target Totals
for Paper
Specification
Reference
Assessment Objective
AO1
AO2
AO3
24
24
12
4
2
7. (h)
1. (d), (h), (i)
2
7
3. (b)
2
4, (a), (b)
1
2. (f)
4. (b)(i)(ii)
7. (f), (n)
2
5. (a)
3. (c), (d), (e),
(f), (g)
1
6. (a)
6. (b)
2. (e), (g)
7. (iv)
9
9
9
9
9
4
9
3
8
4
1
QWC
9
2
1
4
1
6. (c)
7. (i)(ii)(iii)
8
4
4. (a)
HSW
9
2
3. (c)
5. (b)(c)
60
7
3. (a)(i)(ii)
3. (a)(iii)
Total
Mark
1
7. (i), (k)
8. (a)
5. (a)
8. (b)
6. (e)
9. (a)
3. (k), (l)
9. (b)
6. (a), (c)
Raw Totals:
3
4
9
1
6
9
3
2
7
5
25
23
12
60
9
GCSE in CHEMISTRY Specimen Assessment Materials 109
Candidate Name
Centre Number
Candidate Number
0
GCSE
CHEMISTRY
FOUNDATION TIER (Grades G-C)
CHEMISTRY 3 – The chemical industry and analysis
SPECIMEN PAPER
(1 hour)
INSTRUCTIONS TO CANDIDATES
Write your name, centre number and candidate number in the spaces at the top of this
page.
Answer all questions.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded that assessment will take into account the quality of written
communication used in your answer to question 10(b).
GCSE in CHEMISTRY Specimen Assessment Materials 110
Answer all questions.
1.
The fire triangle shows the factors necessary to start and maintain a fire.
(i)
Give the name of the gas present in air which is necessary for burning.
[1]
........................................
(ii)
Give a different fire-fighting method for each of the following situations and
use the fire triangle above to give a reason for your choice of method.
I
A garden bonfire which gets out of control.
[1]
Method ......................................................
Reason ..................................................................................................
II
A beaker of burning ethanol.
[1]
Method ......................................................
Reason ..................................................................................................
III
A science technician with her clothes on fire.
[1]
Method ......................................................
Reason ..................................................................................................
(iii)
Describe one type of fire on which water must not be used.
[1]
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 111
2.
(i)
The table below shows the names, molecular formulae and structural
formulae of some alkanes. The molecular formula for propane is missing.
Complete the table by putting in the missing molecular formula for propane.
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 112
(ii)
Use the four structural formulae drawn below to answer parts I, II and III.
A
B
C
D
Give the letter, A, B, C or D, of the structure which shows
I
ethene, C2H4,
....................
II
[1]
ethanoic acid, CH3COOH,
....................
III
[1]
ethanol, C2H5OH.
....................
[1]
(iii)
wine
vinegar
car battery acid
orange juice
petrol
Choose, from the substances in the box above, the substance which contains
I
ethanol,
....................................................
II
[1]
ethanoic acid.
....................................................
[1]
GCSE in CHEMISTRY Specimen Assessment Materials 113
3.
Limestone and marble are both forms of calcium carbonate, CaCO3. The diagram
below shows the apparatus used to heat a marble chip.
(i)
On heating, marble (calcium carbonate) forms quicklime (calcium oxide) and
carbon dioxide.
Complete the following balanced symbol equation for this reaction by
inserting the correct formulae for calcium oxide and carbon dioxide.
CaCO3
(ii)
......................
+
[2]
.....................
If a few drops of water are dropped onto the cooled quicklime, a violent
reaction takes place.
I
State one observation you would make during this reaction.
[1]
...........................................................................................................................
II
State the colour seen when a piece of universal indicator paper is
dipped into the liquid.
[1]
...........................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 114
4.
Sodium hydroxide solution can be used to distinguish between iron(II) ions and
copper(II) ions. The diagram below shows what happens when sodium hydroxide
solution is carefully added to a solution of an iron(II) compound, such as iron(II)
sulfate.
(i)
I
Sodium hydroxide is a corrosive substance. Give one safety
precaution that should be taken when carrying out the above
experiment.
[1]
...........................................................................................................................
II
Give the chemical formula for iron(II) hydroxide.
[1]
...........................................................................................................................
(ii)
I
The experiment was repeated using copper(II) sulfate solution instead
of iron(II) sulfate. State the colour of the precipitate formed.
[1]
...........................................................................................................................
II
Complete the word equation for the reaction that takes place between
sodium hydroxide and copper(II) sulfate solutions.
[1]
sodium +
hydroxide
copper(II)
sulfate
............................
+
............................
GCSE in CHEMISTRY Specimen Assessment Materials 115
5.
Some scientists believe that drinking small amounts of alcohol reduces the risk of
heart disease. It also helps people feel more confident and helps them relax but can
cause some to become aggressive.
Alcoholic drinks are often referred to in terms of the number of units of alcohol that
they contain. The number of units in a given drink can be calculated using the
following formula.
Number of units =
% alcohol by volume (ABV) × volume of drink (ml)
1000
The National Health Service guidelines state that men should consume a maximum
of 21 units of alcohol per week and women a maximum of 14 units.
(a)
Use the data given below to calculate the number of units consumed by a
man in a given week and state whether or not this exceeds the NHS
guidelines.
[3]
1 × 500 ml of standard beer
2 × 500 ml of standard cider
6 × 175 ml of wine
Drink
Standard beer
Premium lager
Standard cider
Alcopops
Wine
ABV / %
4
5
5
5
12
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
(b)
Drinking the total number of units calculated in part (a) on a single day would
be described as ‘binge drinking’.
Apart from driving under the influence of alcohol, suggest two ways in which
people may put themselves in danger as a result of binge drinking.
[2]
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 116
6.
A sample of dilute hydrochloric acid was titrated with sodium hydroxide solution of
known concentration using the following apparatus.
The titration was carried out four times including a rough initial titration. The results
obtained are shown in the following table.
Rough
titration
1st
2nd
3rd
Final reading / cm3
22.2
42.1
20.6
40.6
Initial reading / cm3
1.5
22.2
0.5
20.6
Volume of
sodium hydroxide added / cm3
20.7
GCSE in CHEMISTRY Specimen Assessment Materials 117
(i)
State why it is always likely that the volume added during the rough titration is
greater than the true value required for neutralisation.
[1]
.......................................................................................................................................
.......................................................................................................................................
(ii)
Give a reason why a funnel used to fill the burette should always be removed
before any measurements are made.
[1]
.......................................................................................................................................
.......................................................................................................................................
(iii)
(iv)
Complete the table by calculating the volume of sodium hydroxide added
during each reaction.
[1]
Calculate the mean volume of sodium hydroxide (in cm3) required for
neutralisation.
[2]
.......................................................................................................................................
.......................................................................................................................................
(v)
Given that the concentration of the sodium hydroxide was 0.1 mol dm−3 state,
giving your reasoning, whether the hydrochloric acid concentration is less
than or greater than 0.1 mol dm−3.
[1]
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 118
7.
Ammonia, NH3, is a very important chemical. It is formed by the reversible reaction
of nitrogen and hydrogen gases and is today manufactured using the Haber process.
A high proportion of ammonia produced is used to make fertilisers.
(a)
State what is meant by a reversible reaction.
[1]
.......................................................................................................................................
(b)
Name the fertiliser made by neutralising ammonia with sulfuric acid.
[1]
.......................................................................................................................................
(c)
The following table shows the average yield of wheat produced by a farmer in
one year using no fertiliser and a variety of fertilisers.
Type of fertiliser
Average yield of
wheat / tonnes
none
0.5
natural
7.2
man-made fertiliser A
6.8
man-made fertiliser B
7.5
man-made fertiliser C
4.9
Using a fertiliser of some description clearly results in improved yields.
State two other conclusions that should be of significant interest to farmers
growing wheat.
[1]
.......................................................................................................................................
.......................................................................................................................................
(d)
Explain how the process of eutrophication leads to fish dying in rivers which
have been polluted by nitrogenous fertilisers.
[3]
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 119
8.
Sarah wants to brew her own beer and needs to know how temperature affects the
fermentation process.
She carried out the following steps:
Add 1g of yeast granules to 20 cm3 of 20 g dm-3 sugar solution at four different
temperatures.
Leave each experiment to stand for 15 minutes.
Measure the height of the froth formed.
ƒ
ƒ
ƒ
She recorded her results in the table below.
Temperature
Froth height / mm
(a)
cold
warm
hot
very hot
1
45
20
3
(i)
Plot Sarah’s results on the following bar chart.
[2]
(ii)
Describe the trend in the amount of fermentation that takes place as
the temperature changes.
[2]
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 120
(b)
(i)
Suggest why the froth height measurements Sarah made during her
investigation are likely to be the least accurate.
[1]
............................................................................................................................
............................................................................................................................
(ii)
What should she do in order to check the quality of her results?
[1]
............................................................................................................................
(iii)
Brian followed Sarah’s instructions carefully as he carried out the
same experiment but his results were significantly different from hers.
Suggest why this may have happened and how you would change the
instructions to make it more likely that every one who did the
experiment would get similar results.
[2]
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 121
9.
(a)
The diagram below shows how sulfur is converted into sulfuric acid by the
Contact process.
sulfur
burned in air
- reacts with oxygen
sulfur dioxide
heated in air over
vanadium(V) oxide
at 450 °C
sulfur trioxide
dissolved in
concentrated sulfuric
acid and then diluted
sulfuric acid
(i)
Balance the following symbol equation for the reversible reaction
between sulfur dioxide and oxygen.
................ SO2 + O2
(ii)
[1]
................ SO3
Give the reason for using vanadium(V) oxide in the conversion in
part (i).
[1]
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 122
(b)
Two experiments were carried out to investigate the volume of carbon dioxide
given off when sodium carbonate reacted with two acids. 50 cm3 of two
acids, ethanoic acid and sulfuric acid, both of equal concentrations were
added separately to the same mass of sodium carbonate powder. The total
volume of carbon dioxide given off was recorded every 10 seconds in the
results table below.
Time / seconds
0
10
20
30
40
50
60
Volume of carbon dioxide
from ethanoic acid / cm3
0
15
27
37
44
49
50
Volume of carbon dioxide
from sulfuric acid / cm3
0
25
40
48
50
50
50
(i)
Using the table above, plot the results for ethanoic acid on the grid
below and draw the curve of best fit.
The curve for sulfuric acid has been done for you.
[3]
GCSE in CHEMISTRY Specimen Assessment Materials 123
(ii)
I
II
Use the graph to find the time taken to collect 35 cm3 of gas
during the reaction with sulfuric acid.
................................. seconds
[1]
State which acid reacted more quickly with the sodium
carbonate and give a reason for your answer.
[2]
............................................................................................................................
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 124
10.
(a)
The following observations were made on testing unknown gas X.
colourless
pungent smell
extinguishes a lighted splint
turns damp red litmus paper blue
(i)
Give one piece of evidence that shows gas X to be an alkaline gas. [1]
............................................................................................................................
(ii)
Name gas X.
[1]
............................................................................................................................
(b)
A student was given three unlabelled beakers containing crystals of
ammonium chloride, ammonium nitrate and sodium chloride.
Describe a method to positively identify each solid using the lowest possible
number of reactions. Give the expected observation in each case when a
reaction takes place.
[6 QWC]
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 125
FORMULAE FOR SOME COMMON IONS
POSITIVE IONS
NEGATIVE IONS
NAME
FORMULA
NAME
FORMULA
Aluminium
Al3+
Bromide
Br
Ammonium
NH4+
Carbonate
CO32-
Barium
Ba2+
Chloride
CI-
Calcium
Ca2+
Fluoride
F-
Copper(II)
Cu2+
Hydroxide
OH-
Hydrogen
H+
Iodide
I-
Iron(II)
Fe2+
Nitrate
NO3-
Iron(III)
Fe3+
Oxide
O2-
Lithium
Li+
Sulfate
SO42-
Magnesium
Mg2+
Nickel
Ni2+
Potassium
K+
Silver
Ag+
Sodium
Na+
-
GCSE in CHEMISTRY Specimen Assessment Materials 126
GCSE in CHEMISTRY Specimen Assessment Materials 127
Candidate Name
Centre Number
Candidate Number
0
GCSE
CHEMISTRY
HIGHER TIER (Grades D-A*)
CHEMISTRY 3 – The chemical industry and analysis
SPECIMEN PAPER
(1 hour)
INSTRUCTIONS TO CANDIDATES
Write your name, centre number and candidate number in the spaces at the top of this
page.
Answer all questions.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded that assessment will take into account the quality of written
communication used in your answer to questions 3(b) and 6.
GCSE in CHEMISTRY Specimen Assessment Materials 128
1.
Sarah wants to brew her own beer and needs to know how temperature affects the
fermentation process.
She carried out the following steps:
Add 1g of yeast granules to 20 cm3 of 20 g dm-3 sugar solution at four different
temperatures.
Leave each experiment to stand for 15 minutes.
Measure the height of the froth formed.
ƒ
ƒ
ƒ
She recorded her results in the table below.
Temperature
Froth height / mm
(a)
cold
warm
hot
very hot
1
45
20
3
(i)
Plot Sarah’s results on the following bar chart.
[2]
(ii)
Describe the trend in the amount of fermentation that takes place as
the temperature changes.
[2]
................................................................................................................
................................................................................................................
................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 129
(b)
(i)
Suggest why the froth height measurements Sarah made during her
investigation are likely to be the least accurate.
[1]
............................................................................................................................
............................................................................................................................
(ii)
What should she do in order to check the quality of her results?
[1]
............................................................................................................................
(iii)
Brian followed Sarah’s instructions carefully as he carried out the
same experiment but his results were significantly different from hers.
Suggest why this may have happened and how you would change the
instructions to make it more likely that every one who did the
experiment would get similar results.
[2]
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 130
2.
(a)
The diagram below shows how sulfur is converted into sulfuric acid by the
Contact process.
sulfur
burned in air
- reacts with oxygen
sulfur dioxide
heated in air over
vanadium(V) oxide at
450 °C
sulfur trioxide
dissolved in
concentrated sulfuric
acid and then diluted
sulfuric acid
(i)
Balance the following symbol equation for the reversible reaction
between sulfur dioxide and oxygen.
................ SO2 + O2
(ii)
[1]
................ SO3
Give the reason for using vanadium(V) oxide in the conversion in
part (i).
[1]
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 131
(b)
Two experiments were carried out to investigate the volume of carbon dioxide
given off when sodium carbonate reacted with two acids. 50 cm3 of two
acids, ethanoic acid and sulfuric acid, both of equal concentrations were
added separately to the same mass of sodium carbonate powder. The total
volume of carbon dioxide given off was recorded every 10 seconds in the
results table below.
Time / seconds
0
10
20
30
40
50
60
Volume of carbon dioxide
from ethanoic acid / cm3
0
15
27
37
44
49
50
Volume of carbon dioxide
from sulfuric acid / cm3
0
25
40
48
50
50
50
(i)
Using the table above, plot the results for ethanoic acid on the grid
below and draw the curve of best fit.
The curve for sulfuric acid has been done for you.
[3]
GCSE in CHEMISTRY Specimen Assessment Materials 132
(ii)
I
II
Use the graph to find the time taken to collect 35 cm3 of gas
during the reaction with sulfuric acid.
................................. seconds
[1]
State which acid reacted more quickly with the sodium
carbonate and give a reason for your answer.
[2]
............................................................................................................................
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 133
3.
(a)
The following observations were made on testing unknown gas X.
colourless
pungent smell
extinguishes a lighted splint
turns damp red litmus paper blue
(i)
Give one piece of evidence that shows gas X to be an alkaline gas.
[1]
............................................................................................................................
(ii)
Name gas X.
[1]
............................................................................................................................
(b)
A student was given three unlabelled beakers containing crystals of
ammonium chloride, ammonium nitrate and sodium chloride.
Describe a method to positively identify each solid using the lowest possible
number of reactions. Give the expected observation in each case when a
reaction takes place.
[6 QWC]
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 134
4.
(a)
Zima and Aled wanted to test the following hypothesis.
‘The carbonates of Group 1 and Group 2 metals do not decompose on
heating.’
Aled heated the three metal carbonates in open boiling tubes and recorded
the following observations.
Observation
sodium carbonate
white solid, no obvious change on heating
calcium carbonate
white solid, no obvious change on heating
copper(II) carbonate
green powder turns black on heating
Zima attached some tubing to her boiling tubes in order to pass the
expanding gas through limewater as each compound was heated. Her
observations are as follows.
Effect of heating
Effect of gas on
limewater
sodium carbonate
white powder,
no obvious change
no change
calcium carbonate
white powder,
no obvious change
turns milky
green powder,
turns black
turns milky
copper(II) carbonate
(i)
By referring to both tables of observations, state to what extent the
evidence supports the hypothesis.
[2]
............................................................................................................................
............................................................................................................................
............................................................................................................................
(ii)
Zima proposed that the carbonates of Group 1 metals do not
decompose on heating.
Describe how she should test this hypothesis.
[1]
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 135
(b)
Limestone is made mainly from calcium carbonate.
Quicklime (calcium oxide) is made by heating limestone.
(i)
Limewater is made by adding calcium oxide to water. Write a
balanced symbol equation for the reaction that occurs.
[2]
............................................................................................................................
(ii)
State one large-scale use of limestone.
[1]
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 136
5.
The structural formulae of five compounds are shown below.
(i)
Give the name of the carbon compound which has the molecular formula
[1]
C2H5OH.
....................
(ii)
Give the letters of two carbon compounds which have the general formula
CnH2n.
[1]
.................... and ....................
(iii)
C5H12 has three different isomers. The structural formula of one isomer is
given below.
Give the structural formula of both other isomers of C5H12.
[2]
GCSE in CHEMISTRY Specimen Assessment Materials 137
(iv)
I
Describe what would be seen as compound D is bubbled through a
brown solution of bromine water.
[1]
............................................................................................................................
II
State what conclusion can be drawn from this test.
[1]
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 138
6.
Describe and explain the conditions used when ammonia is produced from hydrogen
and nitrogen in the Haber process. Discuss how these conditions affect the reaction
rate, yield and profitability of production.
[6 QWC]
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 139
7.
In order to calculate the concentration of a sample of dilute hydrochloric acid, the
acid was titrated with sodium hydroxide solution of known concentration using the
following apparatus.
The titration was carried out four times including a rough initial titration. The results
obtained are shown in the following table.
Rough
titration
1st
2nd
3rd
Final reading / cm3
22.2
42.1
20.6
40.6
Initial reading / cm3
1.5
22.2
0.5
20.6
Volume of
sodium hydroxide added / cm3
20.7
GCSE in CHEMISTRY Specimen Assessment Materials 140
(i)
Explain why it is always likely that the volume added during the rough titration
is greater than the true value required for neutralisation.
[1]
.......................................................................................................................................
.......................................................................................................................................
(ii)
Explain why a funnel used to fill the burette should always be removed before
any measurements are made.
[1]
.......................................................................................................................................
.......................................................................................................................................
(iii)
Complete the table by calculating the volume of sodium hydroxide added
during each reaction. Calculate the mean volume required for neutralisation.
[3]
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
(iv)
Given that the concentration of the sodium hydroxide solution was
0.1 mol dm–3, and using your answer to (iii), calculate the number of moles of
sodium hydroxide added to the acid.
[2]
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
(v)
The balanced symbol equation for the reaction between hydrochloric acid and
sodium hydroxide is as follows.
HCl
+
NaOH
NaCl
+
H2O
State the number of moles of hydrochloric acid in the flask.
[1]
.......................................................................................................................................
(vi)
Calculate the concentration of the hydrochloric acid.
[2]
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 141
8.
(a)
Aqueous sodium hydroxide solution can be used to distinguish between ions
such as Fe2+ and Cu2+.
The reaction of aqueous sodium hydroxide with an aqueous solution of iron(II)
sulfate, FeSO4, can be summarised by the following diagrams.
(i)
Give the meaning of the term aqueous.
[1]
............................................................................................................................
............................................................................................................................
(ii)
Describe what you would see if the above reaction had been repeated
using copper(II) sulfate solution instead of iron(II) sulfate solution. [2]
............................................................................................................................
............................................................................................................................
(iii)
(b)
Give the balanced symbol equation for the reaction that took place
between sodium hydroxide and copper(II) sulfate in part (ii).
[3]
Describe a chemical test you could use to identify the presence of sulfate ions
in solutions such as iron(II) sulfate, giving the expected observation.
[2]
............................................................................................................................
............................................................................................................................
GCSE in CHEMISTRY Specimen Assessment Materials 142
FORMULAE FOR SOME COMMON IONS
POSITIVE IONS
NEGATIVE IONS
NAME
FORMULA
NAME
FORMULA
Aluminium
Al3+
Bromide
Br-
Ammonium
NH4+
Carbonate
CO32-
Barium
Ba2+
Chloride
CI-
Calcium
Ca2+
Fluoride
F-
Copper(II)
Cu2+
Hydroxide
OH-
Hydrogen
H+
Iodide
I-
Iron(II)
Fe2+
Nitrate
NO3-
Iron(III)
Fe3+
Oxide
O2-
Lithium
Li+
Sulfate
SO42-
Magnesium
Mg2+
Nickel
Ni2+
Potassium
K+
Silver
Ag+
Sodium
Na+
GCSE in CHEMISTRY Specimen Assessment Materials 143
GCSE in CHEMISTRY Specimen Assessment Materials 145
MARK SCHEMES
GCSE in CHEMISTRY Specimen Assessment Materials 147
General Marking Instructions
1.
Over-rigidity in the interpretation of the mark scheme is not intended and it is
accepted that points may be made in a variety of different ways including converse
and counterpoints.
2.
Phonetic spelling is allowed except where there is a possibility that scientific terms
might be confused.
3.
When candidates list alternative answers to short answer questions, the general
principle to be followed is: right + wrong = no mark. In a question requiring a set
number of responses, where a candidate has supplied extra responses above the
required number each error/contradiction negates one correct response, however
responses considered neutral (i.e. not incorrect) are not penalised.
4.
The principle of error carried forward is generally applied where an incorrect value
calculated in one part of a question is treated as being correct for the purposes of
subsequent parts.
5.
When marking calculations, substitution into an incorrect equation is not credited and
hence subsequent calculations within that section will score zero.
6.
Alternative answers are accepted even if not noted on the marking scheme as long
as they are appropriate, correct and valid in the context of the science. Note that in
some cases specific terms are a requirement. Any uncertainty about the
acceptability of an answer is clarified by consultation with the Principal Examiner or
Team Leader.
7.
Marking Quality of Written Communication: The marking scheme for these questions
includes indicative content which gives the outline of the content of a good answer.
Candidates should generally cover most, if not quite all, of the points in the indicative
content to achieve the highest mark band on these questions and if candidates
present alternative valid approaches these are equally acceptable. The tests to be
applied are coherence, which is expressed well scientifically, as well as
completeness and correct science at an appropriate level.
8.
Abbreviations used in mark schemes.
/
=
alternatives
not
=
unacceptable answer(s)
accept
=
not an ideal answer but just accepted on this occasion
(…..)
=
further material that would be required for a full answer but is not
required on this occasion
GCSE in CHEMISTRY Specimen Assessment Materials 148
Chemistry 3 Marking Scheme
Foundation Tier
Question
1.
Details
Marks
(i)
oxygen
1
(ii)
I
method and reason needed (no answer credited twice)
water and removes heat / foam and removes air
1
II
method and reason needed (no answer credited twice)
carbon dioxide and removes air /
(fire) blanket / fire proof mat and removes air
1
III
method and reason needed (no answer credited twice)
(fire) blanket / roll person over and over and
removes air /
water and removes heat /
CO2 extinguisher and removes air
1
(iii)
1
electrical fires
burning sodium / Group 1 metal
chip pan fire / burning oil / petrol
Total marks for question
2.
(i)
C3H8
(ii)
I
II
III
A
C
B
1
1
1
(iii)
I
II
wine
vinegar
1
1
6
1
Total marks for question
3.
(i)
(ii)
CaO (1)
CO2 (1)
I
II
4.
5
2
chip breaks up / crumbles / shatters
steam forms / water boils / hisses / fizzes
blue / purple
Total marks for question
1
1
4
(i)
I
II
wear goggles / safety glasses
Fe (OH)2
1
1
(ii)
I
II
blue
copper(II) hydroxide + sodium sulfate – both needed
(allow copper hydroxide)
Total marks for question
1
1
4
GCSE in CHEMISTRY Specimen Assessment Materials 149
Question
Details
5.
correct total volume of cider and wine calculated
i.e. 1000 (ml) of cider and 1050 (ml) of wine (1)
(a)
Marks
formula correctly applied for each drink giving 2, 5 and 12.6
(units)
– mark consequentially (1)
total number of units given i.e. 19.6 and appropriate
comparison with 21 unit maximum – mark consequentially (1)
(b)
3
(1) each for up to 2 valid points relating to
becoming unconscious / falling into a coma / death
dangers associated with falling asleep e.g. in dangerous
places, choking on vomit
over-confidence e.g. doing dangerous things such as crossing
busy roads, climbing walls, swimming in rivers
getting involved with strangers – drugs, crime, sex, violence
2
or other reasonable response
Total marks for question
6.
(i)
5
more alkali than necessary is likely to be added during rough
titration / likely to add further alkali after colour change
happens / likely to overshoot endpoint when alkali is added
quickly
1
more solution could drop from funnel (making volume added
different to measured value)
1
(iii)
all three values correctly calculated – 19.9, 20.1, 20.0
1
(iv)
correct method used to calculate a mean
(1)
calculated without rough titration to get value of 20.0 (cm3) (1)
2
hydrochloric acid has concentration less than sodium
hydroxide solution because less alkali than acid required to
achieve a neutral solution / explanation in terms of n = cV
1
(ii)
(v)
Total marks for question
6
GCSE in CHEMISTRY Specimen Assessment Materials 150
Question
Details
7.
reaction that proceeds in both directions /
products reform reactants
1
(b)
ammonium sulfate
1
(c)
(for this particular crop) fertiliser B is best and
fertiliser C is least effective / natural fertiliser is better than
fertilisers A and C
1
(a)
(d)
Marks
leads to overgrowth / increased numbers of algae (1)
abundance of dead algae for bacteria to feed on so population
grows rapidly/significantly
(1)
the third mark should only be awarded if the candidate
coherently links the drop in oxygen levels to growth in bacteria
numbers
use up oxygen in the water
(1)
Total marks for question
3
6
GCSE in CHEMISTRY Specimen Assessment Materials 151
Question
8.
(a)
Details
(i)
all three bars plotted correctly (2)
any two bars plotted correctly (1) – tolerance ± ½ square
2
very little fermentation in cold solution and significant amount
in warm solution / more fermentation as solution is warmed
(1)
amount of fermentation decreases as solution gets hotter
(1)
2
any sensible practical difficulties involved in measuring froth
height
e.g. column of froth is not uniformly shaped/changes shape
(over time)
not straightforward to measure inside the table with a ruler on
the outside
1
(ii)
repeat each experiment
1
(iii)
used solutions of different temperatures
state clearly the temperature of each solution
(ii)
(b)
Marks
(i)
(1)
(1)
Total marks for question
9.
(a)
(b)
2
8
(i)
correctly balanced i.e. 2 molecules each of SO2 and SO3
1
(ii)
(acts as a) catalyst / speeds up reaction /
increases the rate of reaction
1
(i)
(ii)
all points correctly plotted
one point incorrect
no mark if more than one point incorrect
– tolerance ± ½ square
smooth curve attempted
I
II
(2)
(1)
3
(1)
1
16 – no tolerance
sulfuric acid
(1)
stronger acid / lower pH /
steeper curve / gas given off more quickly / finishes in a
shorter time
(1)
Total marks for question
2
8
GCSE in CHEMISTRY Specimen Assessment Materials 152
Question
10.
(a)
(b)
Details
Marks
(i)
turns damp red litmus paper blue
1
(ii)
ammonia
1
Indicative content: Tests for ammonium ions and chloride
ions carried out in succession, second test on the two
remaining unknown solids only and correct observations
given e.g. NaOH(aq) is added to each solid, both ammonium
salts give pungent smell (ammonia) therefore third is sodium
chloride; ammonium salts dissolved in water and tested with
AgNO3, ammonium chloride gives white precipitate and final
solid is therefore ammonium nitrate. Credit alternative
approach such as chloride ion test first or identification of
sodium chloride by flame test.
6
5 – 6 marks
The candidate constructs an articulate, integrated
account correctly linking relevant points, such as
those in the indicative content, which shows
sequential reasoning. The answer fully addresses
the question with no irrelevant inclusions or
significant omissions. The candidate uses
appropriate scientific terminology and accurate
spelling, punctuation and grammar.
3 – 4 marks
The candidate constructs an account correctly
linking some relevant points, such as those in the
indicative content, showing some reasoning. The
answer addresses the question with some
omissions. The candidate uses mainly appropriate
scientific terminology and some accurate spelling,
punctuation and grammar.
1 – 2 marks
The candidate makes some relevant points, such
as those in the indicative content, showing limited
reasoning. The answer addresses the question
with significant omissions. The candidate uses
limited scientific terminology and inaccuracies in
spelling, punctuation and grammar.
0 marks
The candidate does not make any attempt or
give a relevant answer worthy of credit.
Total marks for question
8
GCSE in CHEMISTRY Specimen Assessment Materials 153
Chemistry 3 Marking Scheme
Higher Tier
Question
1.
(a)
Details
(i)
all three bars plotted correctly (2)
any two bars plotted correctly (1) – tolerance ± ½ square
2
very little fermentation in cold solution and significant amount
in warm solution / more fermentation as solution is warmed
(1)
amount of fermentation decreases as solution gets hotter
(1)
2
any sensible practical difficulties involved in measuring froth
height e.g. column of froth is not uniformly shaped/changes
shape (over time)
not straightforward to measure inside the table with a ruler on
the outside
1
(ii)
repeat each experiment
1
(iii)
used solutions of different temperatures
state clearly the temperature of each solution
(ii)
(b)
Marks
(i)
(1)
(1)
Total marks for question
2.
(a)
(b)
2
8
(i)
correctly balanced i.e. 2 molecules each of SO2 and SO3
1
(ii)
(acts as a) catalyst / speeds up reaction /
increases the rate of reaction
1
all points correctly plotted
(2)
one point incorrect
(1)
no mark if more than one point incorrect – no tolerance
smooth curve attempted
(1)
3
(i)
(ii)
I
II
16 – no tolerance
sulfuric acid
(1)
stronger acid / lower pH /
steeper curve / gas given off more quickly / finishes in a
shorter time
(1)
Total marks for question
1
2
8
GCSE in CHEMISTRY Specimen Assessment Materials 154
Question
3.
(a)
(b)
Details
Marks
(i)
turns damp red litmus paper blue
1
(ii)
ammonia
1
Indicative content: Tests for ammonium ions and chloride
ions carried out in succession, second test on the two
remaining unknown solids only and correct observations
given e.g. NaOH(aq) is added to each solid, both ammonium
salts give pungent smell (ammonia) therefore third is sodium
chloride; ammonium salts dissolved in water and tested with
AgNO3, ammonium chloride gives white precipitate and final
solid is therefore ammonium nitrate. Credit alternative
approach such as chloride ion test first or identification of
sodium chloride by flame test.
6
5 – 6 marks
The candidate constructs an articulate, integrated
account correctly linking relevant points, such as
those in the indicative content, which shows
sequential reasoning. The answer fully addresses
the question with no irrelevant inclusions or
significant omissions. The candidate uses
appropriate scientific terminology and accurate
spelling, punctuation and grammar.
3 – 4 marks
The candidate constructs an account correctly
linking some relevant points, such as those in the
indicative content, showing some reasoning. The
answer addresses the question with some
omissions. The candidate uses mainly appropriate
scientific terminology and some accurate spelling,
punctuation and grammar.
1 – 2 marks
The candidate makes some relevant points, such
as those in the indicative content, showing limited
reasoning. The answer addresses the question
with significant omissions. The candidate uses
limited scientific terminology and inaccuracies in
spelling, punctuation and grammar.
0 marks
The candidate does not make any attempt or
give a relevant answer worthy of credit.
Total marks for question
8
GCSE in CHEMISTRY Specimen Assessment Materials 155
Question
4.
(a)
(b)
Details
(i)
Marks
Aled’s observations support the hypothesis, neither sodium
carbonate nor calcium carbonate appear to have reacted
(1)
Zima’s observations do not support the hypothesis, Group 2
metal has reacted
(1)
2
(ii)
heat all Group 1 carbonates (and test gas with limewater)
1
(i)
CaO
2
(ii)
production of iron / steel / in road building / to neutralise soil
acidity / to make cement – any one
+
H2O
→
Ca(OH)2
Total marks for question
5.
1
6
(i)
ethanol
1
(ii)
B and D – both needed
1
(iii)
H
H
H
H
H
C
C
C
C
H
H
H
H
H
C
H
H
(1)
H
H
C
H
H
H
H
C
C
C
H
H
H
C
H
(iv)
I
II
H
H
(1)
decolourised / turns colourless
compound D is an alkene/unsaturated/contains C=C
Total marks for question
2
1
1
6
GCSE in CHEMISTRY Specimen Assessment Materials 156
Question
Details
Marks
6.
Indicative content: Temperature 400-500°C and pressure 150-300
atm. Reaction rate is reasonable at moderately high temperature
but yield is low so conditions chosen are a compromise. Yield would
be greater at higher pressure but additional plant cost/safety issues
outweigh benefits. Overall yield is 15-25% under these conditions.
Reaction rate is further increased by the use of iron catalyst and
unreacted hydrogen and nitrogen are recycled so not wasted.
Combination of factors allows most profitable production over a
period of time.
5 – 6 marks
The candidate constructs an articulate, integrated
account correctly linking relevant points, such as those in
the indicative content, which shows sequential
reasoning. The answer fully addresses the question with
no irrelevant inclusions or significant omissions. The
candidate uses appropriate scientific terminology and
accurate spelling, punctuation and grammar.
3 – 4 marks
The candidate constructs an account correctly linking
some relevant points, such as those in the indicative
content, showing some reasoning. The answer
addresses the question with some omissions. The
candidate uses mainly appropriate scientific terminology
and some accurate spelling, punctuation and grammar.
1 – 2 marks
The candidate makes some relevant points, such as
those in the indicative content, showing limited
reasoning. The answer addresses the question with
significant omissions. The candidate uses limited
scientific terminology and inaccuracies in spelling,
punctuation and grammar.
0 marks
The candidate does not make any attempt or give a
relevant answer worthy of credit.
Total marks for question
6
6
GCSE in CHEMISTRY Specimen Assessment Materials 157
Question
7.
Details
Marks
(i)
more alkali than necessary is likely to be added during rough
titration / likely to add further alkali after colour change
happens / likely to overshoot endpoint when alkali is added
quickly
(ii)
more solution could drop from funnel (making volume added
different to measured value)
1
all three values correctly calculated – 19.9, 20.1, 20.0
(1)
correct method used to calculate a mean
(1)
calculated without rough titration to get value of 20.0 (cm3) (1)
3
n(NaOH) = 0.1 × 20.0 (1) = 0.002 (mol) (1)
1000
2
1
(iii)
(iv)
(v)
ratio 1:1 therefore n(HCl) = 0.002 (mol) – mark consequentially
(vi)
conc = 0.002
(1) = 0.08 (mol dm-3) (1) – mark
consequentially
25/1000
Total marks for question
8.
(a)
(i)
dissolved in water / solution in water
(ii)
blue solution
blue precipitate forms
(iii)
2
10
1
(1)
(1)
2
correct formulae for both reactants - NaOH and CuSO4
(1)
correct formulae for both products - Na2SO4 and Cu(OH)2 (1)
equation balanced
(1)
– formulae must be correct to gain balancing mark
accept ionic equation alternative
correct formulae for both reactants - Cu2+ and OH- (1)
correct formula for product - Cu(OH)2
(1)
equation balanced (1)
– formulae must be correct to gain balancing mark
(b)
1
add barium chloride / BaCl2
white precipitate forms
3
(1)
(1)
2
Total marks for question
8
GCSE in CHEMISTRY Specimen Assessment Materials 159
ASSESSMENT GRIDS
GCSE in CHEMISTRY Specimen Assessment Materials 161
MARK SPECIFICATION GRID
Chemistry 3
Specimen unit examination
FOUNDATION TIER
C3 – The chemical industry
and analysis
Target Totals
for Paper
Question
Number
2. (iii)
3. (i)
3. (ii)
4. (i)
4. (ii)
5.
AO2
AO3
24
24
12
3
1. (k)
1. (a), (h), (l)
4. (a), (b)
5. (c)
1. (h), (i)
2
2
1
1
3
1
10. (b)
1
3
3. (f)
5
9
6
1
2. (a), (f), (g),
(h)
5
1
6
9
2
8
9
2
1. (f)
9
4
1
1. (m)
2. (d), (e)
1
1
5. (a), (b), (e)
Raw Totals:
8
3
9. (b)(ii)
10. (a)
4
2
9. (a)(i)
9. (b)(i)
4
2
8. (b)
9. (a)(ii)
6
2
8. (a)(i)
8. (a)(ii)
QWC
5
4
6. (v)
7.
HSW
1
6. (i)(ii)
6. (iii)(iv)
60
1
1. (iii)
2. (i)(ii)
AO1
Total
Mark
Specification
Reference
1. (i)
1. (ii)
Assessment Objective
2
5
1
23
24
9
2
8
13
60
9
GCSE in CHEMISTRY Specimen Assessment Materials 162
MARK SPECIFICATION GRID
Chemistry 3
Specimen unit examination
HIGHER TIER
C3 – The chemical industry and
analysis
Target Totals
for Paper
Question Number
Assessment Objective
AO1
AO2
AO3
24
24
12
60
HSW
2
8
9
2
1. (f)
1. (b)
2. (b)(i)
1
1. (m)
2. (d)(e)
1
3. (b)
1
5. (a), (b), (e)
5
1
4. (a), (b), (d)
1
2
3
1
5. (iv)
1. (a), (c)
5. (f)
6.
2. (b)
5
7. (i)(ii)(iii)
7. (iv)(v)(vi)
2
10
3
8. (b)
3
8
2
Raw Totals:
24
24
9
6
5
5. (c), (e)
9
6
1
3
9
9
6
2
3. (d), (f), (g)
8. (a)(i)(ii)
8. (a)(iii)
8
1
2
4. (b)
5. (i)(ii)(iii)
9
2
2
4. (a)(i)
4. (a)(ii)
8
3
2. (b)(ii)
3. (a)
9
4
2. (a)(i)
2. (a)(ii)
QWC
Specification
Reference
1. (a)(i)
1. (a)(ii)
Total
Mark
12
60
9
GCSE in CHEMISTRY Specimen Assessment Materials 163
CONTROLLED
ASSESSMENT
GCSE in CHEMISTRY Specimen Assessment Materials 165
Assessment area
Mark
Awarded
Hypothesising &
planning / 12
Collecting, reviewing
& processing data / 12
Analysing and reviewing
procedure / 12
Analysing data &
concluding / 12
GCSE Chemistry: Investigation
Controlled Assessment
TOTAL / 48
Candidate Name ...............................................................................
Centre Name ......................................................................
Centre Number ..................
Declaration by candidate
I have read and understood the Notice to Candidates (GCSE and Principal Learning:
Controlled Assessments). I have produced the attached work without assistance other
than that which is acceptable under the scheme of assessment.
Candidate's name: ........................................................................................................
Candidate's signature: ...................................................
Date .................................
Declaration by teacher or lecturer
I confirm that:
1.
the candidate's work was conducted under the conditions laid out by the
specification;
2.
I have authenticated the candidate's work and am satisfied that, to the best of my
knowledge, the work produced is solely that of the candidate.
Teacher's name: ........................................................................................................
Teacher's signature: ...................................................
Year - SPECIMEN
Date .................................
GCSE in CHEMISTRY Specimen Assessment Materials 166
Chemistry: Controlled Assessment
Investigating hand warmers
Using an exothermic reaction
Many people who enjoy outdoor activities such as fishing, hill-walking or skiing may have
used ‘hand warmers’ during particularly cold weather. There are different types available to
buy but they all make use of an exothermic reaction which releases heat when two
chemicals react inside them.
Your task is to discover exactly what should be included in your hand warmer in order to
ensure that the greatest amount of heat is produced.
PART 1 – this part is not assessed
Before you do the assessed part of this controlled assessment you will carry out preliminary
work on exothermic and endothermic reactions. You may do this either on your own, in small
groups, as part of a whole class piece of work or your teacher may demonstrate this to you.
You should write a brief report on this preliminary work including:
y
y
results
analysis of the results
GCSE in CHEMISTRY Specimen Assessment Materials 167
Investigating hand warmers
PART 2 – this part is assessed
Now you are going to move on to the investigation which you are going to plan and carry
out.
What you should include in your hand warmer to produce the greatest amount of heat.
Investigate this question and write a report of your work. You should include the following
steps:
You should
(a)
(b)
(c)
(d)
(e)
consider the details of the question you are going to investigate – you
can discuss it with other people, including others taking the assessment,
research the topic, e.g. by looking for information on the internet,
produce a hypothesis and give some background information which
supports it,
produce a plan for undertaking the investigation – you should use
information from the work in PART 1,
consider any risks associated with this investigation – you may use the
Risk Assessment sheet for this.
You will do parts (c), (d) and (e) under supervision and without discussing it with
anyone apart from your teacher.
You should now proceed to carry out the investigation and write it up. You will be able
to co-operate with other people in obtaining data but the report must be your own work.
During the carrying out of your investigation you should review your method and
change it if necessary in the light of experience.
Report
Your report should include:
y
y
y
y
a suitable presentation of all your results
evaluations of the results and a discussion of your findings
conclusions and a review of the hypothesis
evaluation of the investigation
Risks
Ways of reducing risks
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Hazards
GCSE Chemistry – Risk Assessment
GCSE in CHEMISTRY Specimen Assessment Materials 168
GCSE in CHEMISTRY Specimen Assessment Materials 169
Teacher Guidance Notes
This controlled assessment task is in the context of section 6 of the Chemistry 2 content, in
particular section 6(e). The task, including the preliminary work is structured as follows:
1.
Preliminary work: The candidates should undertake some experimental work looking
at substances [compounds and elements] which react, to determine whether the
reactions are endothermic or exothermic and to measure temperature changes. The
following substances are offered as possibilities but others are possible:
Solutions
Solids
copper sulfate
ammonium chloride
sulfuric acid
copper oxide
water
magnesium
sodium hydrogencarbonate
zinc
The brief write-up that the candidates produce is not for assessment but to give them
access to the results for planning their investigation.
2.
Collection of secondary data: As part of the planning process, the candidates need to
collect secondary data. These data can be used by the candidates in two ways: to
inform themselves about the repeatability and reproducibility of the data which could
inform their decision about the number of repeats; to provide some evidence which
may be of use in their hypothesising. The secondary data may also be useful in their
analysis / evaluation. The results of other candidates in the preliminary work could be
used and supervisors could provide a data set for the candidates to search. It is
important that the candidates select appropriate data for themselves. Centres
having difficulty in obtaining appropriate data which may be used should contact
WJEC.
3.
Research: This stage of the controlled assessment is carried out under a limited
level of control. Candidates may carry out some work in conditions not under the
supervision of the teacher. The candidates should be given the opportunity to do
some research which can involve internet searches and text books into the factors
which affect the magnitude of the energy release. Supervisors may prepare materials
for candidates to use in this research phase. Copies of these materials should be
included with the candidates’ work.
4.
Planning an investigation: This stage of the controlled assessment is carried out
under a high level of control, i.e. the candidates work individually. The candidates
use the results of their research and their preliminary work to plan an investigation
into one of the factors which may affect the temperature rise in a reaction mixture.
They should:
y
y
y
y
Identify the variables which they intend to investigate;
Identify variables which need to be controlled
Suggest a relationship between the dependent and independent variables
Give reasons for suggesting this relationship – coming from their research and /
or their scientific knowledge
GCSE in CHEMISTRY Specimen Assessment Materials 170
y
y
Give details of their planned procedure – drawing on their experience of the
preliminary work, including the repeatability of the data achieved in it
Include a risk assessment
Note that the plan need not be complete at this stage – it can be modified in the light
of experience, e.g. in the light of experience of the repeat results. It is not anticipated
that the plans occupy more than 2 or 3 sides of A4. This stage of the controlled
assessment may take up to 2 hours of formally assessed time.
5.
Data acquisition: This stage of the controlled assessment is carried out under a
limited level of control, in that candidates with similar plans are allowed to work in
groups. Credit is available in the next phase of the controlled assessment for
reporting decisions made during data acquisition, e.g. modifying the method of fixing
the controlled variables or checking suspect results. It is anticipated that this stage of
the controlled assessment will take up to approximately 2 hours. During this stage,
feedback should be limited to clarification of the requirements of the assessment.
6.
Report writing: This stage of the controlled assessment is carried out under a high
level of control, i.e. the candidates work individually. The candidates present their
data appropriately, e.g. using tables, charts and graphs, chosen to allow the
hypothesis to be tested as rigorously as possible. Any decisions made during data
acquisition, including modifications to the plan should be presented with justification.
The report should include suitable analysis of the data and a conclusion relating to
the hypothesis. The extent and quality of the data should be explored alongside a
discussion on the degree of confidence in the conclusion.
It is anticipated that this stage of the controlled assessment may take up to 3 hours of
formally supervised time. The extent of the report, including tables and graphs,
should occupy not more than 4 sides of A4. The report submitted should include the
candidate's hypothesis, plan and risk assessment.
During this stage, feedback should be limited to clarification of the requirements of
the assessment.
7.
Assessment: This stage of the controlled assessment is carried out under a medium
level of control. Supervisors use the WJEC marking criteria to assess the report
using a “best fit” approach.
GCSE in CHEMISTRY Specimen Assessment Materials 171
Controlled Assessment
Chemistry: Investigation
Marking Criteria
1.
The work of each candidate should be assessed in each of the following fields
1.
2.
3.
4.
Hypothesising and planning
Collecting, reviewing and processing data
Analysing and reviewing procedure
Analysing data and concluding
2.
The maximum mark in each assessment field is 12 and is subdivided into the
following bands:
0 marks, 1 – 3 marks, 4 – 6 marks, 7 – 9 marks, 10 – 12 marks
3.
The bands are hierarchical, however, a “best fit” approach should be adopted, i.e.
minor shortcomings at one level can be overcome by a candidate clearly meeting the
additional demands of a higher level.
4.
The demands of Quality of Written Communication are incorporated into the criteria
in fields 2 and 4.
5.
Centres are required to annotate work to show which level is achieved in each field
and to indicate the evidence for the achievement of the level and position within the
level.
6.
The marks for each of the fields should be entered into the table on the controlled
assessment cover sheet and the authenticating declarations by the candidate and
teacher / lecturer signed and dated.
7.
A single mark out of 48 is submitted.
GCSE in CHEMISTRY Specimen Assessment Materials 172
Hypothesising and planning
Mark
range
0
1-3
Description
Exemplification – indicative assessment points
No evidence of planning is presented.
Candidates work from a given hypothesis and
make a plan to collect some relevant data without
necessarily controlling variables. They take some
account of safety in their plan.
•
•
•
4-6
7-9
Candidates make a simple hypothesis relating the
independent and dependent variables. Plan
identifies independent and dependent variables
without necessarily identifying controlled variables
explicitly. They identify any significant hazards
relating to the investigation.
•
Candidates make a hypothesis relating the
variables to be investigated and discuss it in terms
of scientific knowledge or the results of their
preliminary research. Plan identifies the variables
which need to be controlled and includes ranges
and intervals of variables and appropriate
numbers of repeats. They use the experience of
previous work to produce a simple risk
assessment for the investigation.
•
•
•
•
•
•
•
use a simple, given hypothesis, e.g. zinc and copper sulfate cause a greater
temperature rise than zinc and sulfuric acid, to plan some measurements
plan to
o measure a temperature rise
o repeat a reading at least once
consider the need to work safely, e.g. mention a normal laboratory rule
make a simple qualitative hypothesis e.g. the more magnesium that is added, the
greater the temperature rise of the sulfuric acid
identify mass of magnesium and the temperature rise as the independent and
dependent variables, possibly without stating that volume of acid must be kept
constant
describe a significant hazard e.g. sulfuric acid is corrosive/irritant
relate the hypothesis qualitatively to concept of energy and bond breaking/making
identify explicitly all significant variables including the variables which need to be
controlled e.g. mass of solids, concentration and volume of solutions
plan a range and intervals of the independent variable which should lead to a test of
the hypothesis [at least 5 different and reasonably spaced values]
plan to take at least three readings at each value of the independent variable – or
justify why fewer are sufficient, e.g. from the preliminary work
produce a simple risk assessment for the investigation
GCSE in CHEMISTRY Specimen Assessment Materials 173
Hypothesising and planning
Mark
range
Description
10-12
Candidates additionally use the results of scientific
knowledge, preliminary work and research to
justify the hypothesis.
They explain how they control variables and justify
the need to control specific variables in terms of a
valid investigation (or discuss the limitations of the
investigation where variables cannot be
controlled). They discuss and use the results of
preliminary work to inform details of the plan, e.g.
in terms of ranges and number of repeats and any
relevant safety issues.
Exemplification – indicative assessment points
•
•
•
use detailed scientific knowledge e.g. the relative amounts of energy required to
break bonds/released by forming bonds during reactions, to justify hypothesis
use their knowledge and understanding of the scientific techniques and chemical
reactions and collision theory to explain why variables e.g. acid concentration needs
to be controlled in order to carry out a valid investigation
use the results of preliminary work, including secondary data, to justify the number
of repeat readings required [in terms of the expected scatter of the individual
readings]
GCSE in CHEMISTRY Specimen Assessment Materials 174
Collecting, reviewing and processing data
Mark
range
0
Description
Exemplification – indicative assessment points
No evidence of collected data presented.
Candidates work safely, they collect some data
relevant to the investigation and display the
collected data.
1-3
•
•
•
4-6
Candidates collect sufficient relevant data which
enable an initial assessment of the validity of the
hypothesis to inform the plan. They select simple
forms and styles of presentation of the data
including a simple table, graph, chart or diagram
which enables data to be interpreted and they
process some data mathematically e.g. by
averaging.
•
•
•
•
•
measure a single temperature rise e.g. when sodium hydrogencarbonate is added
to sulfuric acid
measure the temperature rise for at least two different values of the independent
variable, without necessarily controlling other variables
present the measured values of temperature rise and independent variables – not
necessarily in systematic form or with correct use of units
measure the temperature rise for at least 3 values of the independent variable e.g.
volume of sulfuric acid
repeat a measurement of the temperature rise for at least one value of the
independent variable
make enough measurements of the temperature rise to enable an initial judgement
on the validity of the hypothesis
produce a table of results for at least 3 values of the independent variable e.g.
volume of sulfuric acid, not necessarily including repeat readings of temperature rise
for all volumes, or produce a graph of temperature rise against volume, possibly
lacking precision e.g. when plotting, labelling axes
determine the mean value of temperature rise for at least 3 different volumes
GCSE in CHEMISTRY Specimen Assessment Materials 175
Collecting, reviewing and processing data
Mark
range
7-9
Description
Candidates collect sufficient valid data which
enable them to make a judgement on a simple
hypothesis and review details of the plan in the
light of results. Using standard forms and styles of
presentation appropriate to the task, they display
data systematically, including detailed graph or
chart; they use judgement in the selection and
mathematical processing of data which they
display appropriately.
Exemplification – indicative assessment points
•
•
•
•
•
•
10-12
Candidates collect sufficient high-quality valid data
which enable them to make a good judgement of a
detailed hypothesis and they discuss the
sufficiency of the data, reflecting upon the plan.
They select and effectively use high level forms
and styles of presentation appropriate to the task;
they process data appropriately and accurately
producing a high-level display of the data.
•
•
•
collect data from at least 5 well spread values of the independent variable, e.g.
concentration of copper(II) sulfate solution, and use it to make a judgement on a
qualitative hypothesis
describe any changes made to the details of the plan in light of experience e.g.
number of repeat readings
display data in appropriate sequence in well-organised tables with headings and
units, possibly with minor omissions e.g. units missing in one column
produce a graph, e.g. of temperature rise against concentration of copper(II) sulfate
solution, with good choice of scales and labelled axes (including units), possibly with
one minor plotting error or incomplete axis label
ignore suspect values when calculating means
use a sensible approach to significant figures
produce data that are sufficient [e.g. in terms of spread of concentration of sulfuric
acid solution values and variability of temperature rise values] to test their
hypothesis and consider the sufficiency of the data
display data in well-designed tables with accurate headings and appropriate units in
all cases
produce a graph with accurate scales, labelling and plotting in all cases, drawing a
line of best fit, where appropriate, which can be used to test hypothesis
GCSE in CHEMISTRY Specimen Assessment Materials 176
Analysing and reviewing procedure
Mark
range
0
1-3
4-6
7-9
Description
Exemplification – indicative assessment points
No evidence of analysis or review presented.
Candidates make simple relevant comments
about techniques in the procedure and on the
quality of the evidence produced. They make a
simple statement referring to other data, e.g. in the
preliminary work or research.
•
Candidates make detailed relevant comments
about techniques in the procedure and use the
spread/trend of their raw data to comment on the
repeatability of the data produced. They make a
detailed statement referring to other data, e.g. in
the preliminary work or research.
•
Candidates suggest changes to the techniques in
the procedure. They justify improvements in terms
of the repeatability of the measurements or justify
an assertion that no improvement is necessary.
They comment on other data, e.g. in the
preliminary work or research.
•
•
•
•
•
•
•
make a simple statement about the process of carrying out their investigation e.g. it
was difficult to measure the correct amount of zinc for each reaction
make a simple, possibly incorrect, statement about how accurate they think the data
are, without any reasoning
state how data compares with preliminary work e.g. temperature rise was the same
as it was during preliminary work
expand on a simple statement, possibly by adding some explanation e.g. difficult to
know exactly how much more powder is needed to get to the next required amount
make a statement which refers to how spread out the individual readings for a
particular value of the temperature rise were
comment on how results compare with those from preliminary work (possibly
including other groups’ data) or how the observed relationship, e.g. change in
temperature rise with change in copper(II) sulfate solution concentration, fits in with
their research
suggest a way of improving the evidence, e.g. by measuring solution volumes more
accurately using a burette, or justify why the evidence does not need improvement
explain how a change to method will improve quality of data collected, e.g.
measured temperature rises will be closer to the true value if solution volumes are
more accurately measured
comment on how results of this investigation support or contradict preliminary work
or research
GCSE in CHEMISTRY Specimen Assessment Materials 177
Analysing and reviewing procedure
Mark
range
10-12
Description
Candidates discuss the limitations of the
investigation. They relate the outcome of the
investigation with information discovered in the
candidate’s research, making a detailed
comparison.
Exemplification – indicative assessment points
•
•
•
•
•
suggest possible reasons why measured values may not be very close to true
values, e.g. heat lost from container as reaction occurs so maximum recorded
temperature will always be lower than true value
examine repeatability and/or reproducibility [data from preliminary work]
discuss to what extent the data support the conclusion
consider whether a different conclusion is also supported by the data
discuss in detail to what extent the data are in line with the initial research
GCSE in CHEMISTRY Specimen Assessment Materials 178
Analysing data and concluding
Mark
range
0
1-3
4-6
7-9
Description
Exemplification – indicative assessment points
No analysis or conclusion presented.
Candidates make a simple, relevant statement
about the data possibly identifying some trends or
patterns in the data. The presentation may have
major inaccuracies of spelling punctuation and
grammar; little use of scientific vocabulary.
•
Candidates give a detailed, accurate description of
the trends or patterns in the data, relating the
trends to information discovered in the candidate’s
research. The presentation has inaccuracies in
spelling punctuation and grammar; use of
scientific vocabulary is limited.
•
Candidates identify the relationship(s) between
variables revealed in the data, relating this to the
hypothesis. They make a comparison of the
outcome of the investigation with information
discovered in the candidate’s research. The
presentation has no major inaccuracies in spelling
punctuation and grammar; use of scientific
vocabulary is good.
•
•
•
•
•
•
•
•
make a correct statement about the data, possibly about only one value of the
temperature rise
make a correct statement, referring to at least two values of the temperature rise
and suggesting a trend
use non-scientific vocabulary, write incomplete sentences and use a style which
requires the assessor to search for relevant points
make a simple statement linking the variation of the temperature rise to that of the
independent variable e.g. the mass of magnesium added to sulfuric acid
comment on how the trend compares with that expected following preliminary work
or research
attempt to construct full sentences and use basic scientific vocabulary but
incorrectly spell a significant proportion of key words
make a qualitative statement linking the variables e.g. the greater the mass of
magnesium added to sulfuric acid, the greater the temperature rise
state that the relationship is broadly in line with the hypothesis, or otherwise, as
appropriate
explain how their results support or contradict their research
use scientific terms appropriately and construct simple sentences, with generally
good spelling, to effectively convey meaning
GCSE in CHEMISTRY Specimen Assessment Materials 179
Analysing data and concluding
Mark
range
10-12
Description
Candidates produce a valid conclusion from the
data collected. They discuss the extent to which
the data support the hypothesis (including whether
an alternative hypothesis is supported) and
discuss the extent to which more/improved quality
of the data would improve their confidence in the
conclusion. The presentation has good spelling
punctuation and grammar; use of scientific
vocabulary is appropriate and of a high standard.
Exemplification – indicative assessment points
•
•
•
•
•
draw a conclusion relating, for example, the mass of magnesium and the
temperature rise, or show that the expected relationship is not supported by the data
examine repeatability and/or reproducibility [data from preliminary work]
discuss to what extent the data support the conclusion e.g. referring to the
maximum amount of magnesium that can be added before sulfuric acid is used up
discuss in detail to what extent the data are in line with the initial research
correctly use a range of scientific terms and express themselves with clarity and
with very few spelling errors
GCSE in CHEMISTRY Specimen Assessment Materials 180
MARK SPECIFICATION GRID
GCSE Chemistry
Controlled Assessment
Assessment Objective
As percentage of the Controlled
Assessment
Marks for the Controlled
Assessment
WJEC GCSE in Chemistry SAMs – 2011/ED
24/2/11
AO1
AO2
AO3
Total
Mark
18.75%
25%
56.25%
100%
9
12
27
48
HSW
QWC
3
3