Chemistry C3 Higher Questions Part 1
Q1.
Ammonia is manufactured from nitrogen and hydrogen in the Haber Process. The
diagram shows some details of the manufacturing process.
(a)
Nitrogen is obtained from the air.
From where is the hydrogen obtained?
.....................................................................................................................................
(1)
(b)
What happens to the unreacted nitrogen and hydrogen?
.....................................................................................................................................
.....................................................................................................................................
(1)
(c)
Ammonium nitrate is made from ammonia.
Farmers spread nitrates on to soil to make crops grow better.
The nitrates may get into people‟s bodies even if they do not eat the crops.
Explain how this can happen.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)
Page 1
Q2.
Some students slowly add solution Y to solution X.
The graph shows what happens to the pH of the solution in the beaker as they do this.
(a)
Choose words from this list to complete the sentences below.
acidic
alkaline
neutral
At point A on the graph the solution in the beaker is ...............................................
At point B on the graph the solution in the beaker is ...............................................
At point C on the graph the solution in the beaker is ...............................................
(2)
(b)
Describe, as fully as you can, what happens to the pH of the mixture as solution Y
is slowly added.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5)
(Total 7 marks)
Page 2
##
Ammonia is manufactured by the Haber Process, where nitrogen and hydrogen react
together as follows:
N2
+
3H2
2NH3
The reaction is reversible. A balance is eventually reached when ammonia is being
formed at the same rate at which it is decomposing.
This point is called „equilibrium‟.
PERCENTAGE OF AMMONIA AT EQUILIBRIUM
PRESSURE (ATM)
100° C
300° C
500° C
25
91.7
27.4
2.9
100
96.7
52.5
10.6
400
99.4
79,7
31.9
(a)
(i)
What is meant by a „reversible reaction‟?
.........................................................................................................................
.........................................................................................................................
(1)
(ii)
Which substances are present in the mixture at equilibrium?
.........................................................................................................................
(1)
(b)
(i)
Under what conditions shown in the table is the maximum yield of
ammonia obtained?
.........................................................................................................................
.........................................................................................................................
(2)
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(ii)
The Haber Process is usually carried out at a higher temperature than that
which would produce the maximum yield. Suggest why.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(2)
(c)
Ammonia can be converted into nitric acid in three stages:
Stage 1
Ammonia reacts with oxygen from the air to form nitrogen monoxide
and water
4NH3
+
5O2
4NO
+
6H2O
Stage 2
On cooling, nitrogen monoxide reacts with oxygen from the air to form
nitrogen dioxide.
Stage 3
Nitrogen dioxide reacts with water to form nitric acid and nitrogen
monoxide.
(i)
Describe the conditions under which the reaction in Stage 1 takes place.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(3)
(ii)
Balance the equation for the reaction at Stage 2.
NO
+
O2
NO2
(1)
(iii)
Balance the equation for the reaction at Stage 3.
Page 4
NO2
+
H2O
HNO3
+
NO
(1)
(d)
The chemical plant for manufacturing ammonia is often on the same site as plants
manufacturing nitric acid and fertilisers.
(i)
What advantages will this have for the manufacturing company?
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(2)
(ii)
Briefly describe two important ways in which it is possible to reduce the
environmental impact of such plants on the surrounding area.
1 ......................................................................................................................
.........................................................................................................................
2 ......................................................................................................................
.........................................................................................................................
(2)
(Total 15 marks)
Q4.
Three elements in Group 2 of the periodic table are beryllium (Be), magnesium (Mg)
and calcium (Ca). Their mass numbers and proton numbers are shown below. The
electronic structure is shown for beryllium and calcium.
Page 5
(a)
In a similar way, draw the electronic structure for magnesium.
(3)
(b)
•
•
The three elements have similar chemical properties
The reactivity of these elements with non-metals, increases from beryllium to
magnesium to calcium.
Explain these two statements in terms of atomic structure.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(6)
(Total 9 marks)
Q5.
Part of the Periodic Table is shown below. Use the information to help you answer the
questions which follow.
Page 6
(a)
Write the symbol for:
(i)
chlorine; .........................................
(ii)
sodium. ..........................................
(2)
(b)
(i)
What is the symbol of the element which is in Group 2 and Period 3?
........................
(ii)
What name is given to Group 7?
..........................................................................................................................
(2)
(c)
The arrangement of electrons in sulphur (S) is 2.8.6.
Write the arrangement of electrons for:
(i)
neon (Ne); ........................................................................................................
(1)
(ii)
aluminium (Al). ...............................................................................................
(1)
(d)
The Periodic Table is an arrangement of elements in order of increasing atomic
number. What is the atomic number of an element?
....................................................................................................................................
(1)
Page 7
(e)
What is the name of the uncharged particle in the nucleus of an atom?
....................................................................................................................................
(1)
(Total 8 marks)
Q6.
Powdered magnesium oxide was added in 0.1 g amounts to 25 cm3 of dilute
hydrochloric acid and the mixture stirred. The powder soon reacted and disappeared, but
after about 1.0 g had been added it took some time for all the solid to react. When a total
of 1.1 g of powder had been added, some of the magnesium oxide remained at the
bottom of the flask.
(a)
On the following axes draw a sketch graph to show how the pH of the liquid is likely
to change during the experiment described above. Start the graph with the pH of the
acid before any magnesium oxide is added.
(3)
(b)
A second experiment was done using magnesium oxide from the same bottle with
25 cm3 of the same hydrochloric acid.
Page 8
There is no catalyst for this reaction. Suggest two ways in which the rate of this
reaction could have been speeded up.
...................................................................................................................................
...................................................................................................................................
(2)
(c)
(i)
What is the symbol for the oxide ion?
...........................................................................................................................
(1)
(ii)
Complete the ionic equation for the reaction between hydrogen ions and oxide
ions.
................................. + .................................  H2O
(2)
(iii)
The experiment was repeated, but 25 cm3 of dilute sulphuric acid was used
instead of hydrochloric acid.
The concentration of the sulphuric acid was the same as the hydrochloric acid
(0.1 M).
Why was twice as much magnesium oxide needed to neutralise the sulphuric
acid completely?
...........................................................................................................................
...........................................................................................................................
(1)
(Total 9 marks)
Q7.
Complete the table which shows some of the physical properties of bromine, chlorine
and iodine.
Bromine
Melting point
in °C
Boiling point
in °C
Physical state
at 23 °C
Colour of
vapour
–7
58
………………..
………………..
Page 9
Chlorine
–101
–34
………………..
greenish
Iodine
–114
183
………………..
………………..
(Total 2 marks)
Q8.
The diagram shows the final stages in the manufacture of ammonia.
(a)
Why is iron used in the converter?
....................................................................................................................................
....................................................................................................................................
(1)
(b)
Write the word equation for the reaction in the converter.
....................................... + .......................................
..................................
(1)
Page 10
(c)
The yield of ammonia is only about 15%.
(i)
Why can the yield not be 100%?
......................................................................................................................
....
......................................................................................................................
....
(1)
(ii)
Describe what happens to the mixture of gases after it leaves the converter.
......................................................................................................................
....
......................................................................................................................
....
......................................................................................................................
....
(2)
(Total 5 marks)
Q9.
Use the periodic table on the Data Sheet to answer these questions.
The table below gives the electronic structures of four elements, W, X, Y and Z.
Element
Electronic structure
W
2,5
X
2,7
Y
2,8,8
Z
2,8,8,1
(a)
Which element W, X, Y or Z:
(i)
is a Group 0 gas? ....................
(ii)
is nitrogen? ....................
(iii)
is a Group 7 gas? ....................
Page 11
(iv)
reacts violently with water? ....................
(3)
(b)
Which two Groups of the periodic table do not contain any non-metals?
....................................................................................................................................
(1)
(Total 4 marks)
Q10.
(a)
(i)
Which acid should the student add to sodium hydroxide solution to
make sodium sulphate?
............................................................. acid
(1)
(ii)
Use the table on the Data Sheet to help you to write the formula of sodium
sulphate.
Formula: ...........................................................................................................
(1)
(b)
The student noticed that the solution in the beaker got warm when the acid reacted
with the alkali.
The energy diagram below represents this reaction.
Page 12
(i)
In terms of energy, what type of reaction is this?
..........................................................................................................................
(1)
(ii)
Use the energy diagram to calculate a value for the amount of energy
released during this reaction.
..........................................................................................................................
Energy released .................... kJ
(1)
Page 13
(iii)
Explain, in terms of bond breaking and bond forming, why energy is released
during this reaction.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(iv)
The reaction takes place very quickly, without the help of a catalyst. What
does this suggest about the activation energy for this reaction?
...........................................................................................................................
...........................................................................................................................
(1)
(Total 8 marks)
Q11.
Part of the Periodic Table which Mendeleev published in 1869 is shown below.
Use the Data Sheet to help you to answer this question.
(a)
Name two elements in Group 1 of Mendeleev‟s Periodic Table which are not found
Page 14
in Group 1 of the modern Periodic Table.
................................................................... and .........................................................
(2)
(b)
Which group of elements in the modern Periodic Table is missing on Mendeleev‟s
table?
....................................................................................................................................
(1)
(c)
Mendeleev left several gaps in his Periodic Table. These gaps are shown as
asterisks(*) on the table above.
Suggest why Mendeleev left these gaps.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(1)
(d)
Complete the following sentence.
In the modern Periodic Table the elements are arranged in the order of their
........................................ numbers.
(1)
(Total 5 marks)
Q12.
Part of the Periodic Table which Mendeleev published in 1869 is shown below.
Page 15
Use the Data Sheet to help you to answer this question.
(a)
(i)
Give the symbols of two elements in Group 1 of Mendeleev‟s Periodic Table
which are not found in Group 1 of the modern Periodic Table.
.......................................................... and .........................................................
(1)
(ii)
Name these two elements.
.......................................................... and .........................................................
(2)
(b)
Which group of elements in the modern Periodic Table is missing on Mendeleev‟s
table?
....................................................................................................................................
(1)
(c)
Mendeleev left several gaps in his Periodic Table. These gaps are shown as
asterisks(*) on the table above.
Suggest why Mendeleev left these gaps.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(1)
Page 16
(d)
Complete the following sentence.
In the modern Periodic Table the elements are arranged in the order of their
........................................ numbers.
(1)
(e)
Mendeleev placed lithium, sodium and potassium in Group 1 of his Periodic Table.
This was because they have similar properties.
Some properties of elements are given in the table.
Four of them are properties of lithium, sodium and potassium. One of these
properties has been ticked for you. Place a tick next to the other three properties.
PROPERTY
They react with water to give alkaline solutions.
They are gases.
They are non-metals.
They form an ion with a 1+ charge.
They react with water and give off hydrogen.
They form an ion with a 1– charge.
They are metals.
They react with water to give acidic solutions.
(3)
(f)
What happens when a small piece of sodium reacts with water?
You should describe what you would see and state what substances are formed.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
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Page 17
(3)
(Total 12 marks)
Q13.
The flow chart below shows the main stages in the production of ammonium nitrate.
(i)
Name the two raw materials shown in the flow chart as A and B by choosing words
from the list.
air
coke
limestone
natural gas
Raw material A ........................................................
Raw material B ........................................................
(2)
Page 18
(ii)
Complete the word equation for the reaction which makes ammonia.
....................................... + ....................................... → ammonia
(1)
(iii)
What is the purpose of the iron in the reactor?
.....................................................................................................................................
.....................................................................................................................................
(1)
(iv)
What is the purpose of pipe C?
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 5 marks)
Q14.
Read the following information about an element X.
The element X melts above 600°C. It conducts electricity at room temperature. It burns in
oxygen to form an oxide. When the oxide is mixed with water it turns Universal Indicator
blue.
The oxide of X is a white solid at room temperature. It has the formula XO and contains
the ion X2+.
The element X reacts with chlorine to form a chloride with a high melting point. The
chloride conducts electricity when molten and it is soluble in water.
(a)
From the information give three pieces of evidence which suggest that X is a metal.
1 ................................................................................................................................
....................................................................................................................................
2 ................................................................................................................................
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....................................................................................................................................
3 ................................................................................................................................
....................................................................................................................................
(3)
(b)
In which Group of the Periodic Table should X be placed? Give a reason for
your answer.
Group .........................................................................................................................
Reason .......................................................................................................................
....................................................................................................................................
(2)
(c)
Predict the formula for the chloride of X. ..................................................................
(1)
(Total 6 marks)
HYDROGEN FUEL OF THE FUTURE
Q15.
It has been suggested that hydrogen could be used as a fuel instead of the fossil fuels
that are used at present. The equation below shows how hydrogen burns in air.
2H2 + O2 → 2H2O + heat
The hydrogen would be made from water using energy obtained from renewable sources
such as wind or solar power. The water splitting reaction requires a lot of energy.
(a)
Hydrogen was successfully used as a fuel for a Soviet airliner in 1988.
Why would hydrogen be a good fuel for use in an aeroplane?
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
Page 20
(2)
(b)
The water splitting reaction is shown in the equation below.
2H2O →
2H2 + O2
Calculate the energy needed to split the water molecules in the equation into H
and O atoms.
2H2O
→
4H
+
2O
.....................................................................................................................................
.....................................................................................................................................
(2)
(c)
On the Periodic Table, hydrogen is placed on its own at the top and in the middle. It
is difficult to position it because it has the properties of metals and non-metals.
(i)
Where would you expect hydrogen to be placed on the periodic table on the
basis of the arrangement of electrons in hydrogen atoms?
...........................................................................................................................
...........................................................................................................................
(1)
Explain your answer.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
Give one way in which hydrogen behaves like a metal.
...........................................................................................................................
...........................................................................................................................
(1)
(iii)
Give one way in which hydrogen behaves like a non-metal.
Page 21
...........................................................................................................................
...........................................................................................................................
(1)
(Total 8 marks)
Q16.
The chemical compositions of two samples of hard water, A and B, are shown in the
table.
pH
Ions present:
(a)
Sample A
Sample B
9
8
Concentration in mg/litre
Ca2+
101
135
Mg2+
2
9
Na+
9
6
HCO3–
299
6
CI–
14
8
SO42–
5
136
NO3–
6
0
What does the pH value tell you about these samples?
.....................................................................................................................................
(2)
(b)
Use the information in the table to explain what is meant by hard water.
.....................................................................................................................................
.....................................................................................................................................
(1)
Page 22
(c)
What would be the effect of using temporarily hard water in a kettle?
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(d)
(i)
Explain which sample of water is permanently hard.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(ii)
How could this hardness be removed?
...........................................................................................................................
...........................................................................................................................
(1)
(e)
State one advantage of drinking hard water.
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 10 marks)
Q17.
The Periodic Table contains groups of elements that have similar chemical
properties.
(a)
The halogens are in Group 7 of the Periodic Table.
(i)
Complete the table. Iodine has been done for you.
Page 23
Halogen
Colour of vapour
chlorine
red-brown
iodine
purple
(2)
(ii)
Why do the halogens have similar chemical properties?
...........................................................................................................................
...........................................................................................................................
(1)
(b)
The alkali metals are in Group 1 of the Periodic Table. State what is formed when
any alkali metal reacts with water.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 5 marks)
Q18.
The flow diagram shows some stages in the manufacture of ammonium nitrate,
NH4NO3.
Page 24
(a)
Which elements are obtained from the raw materials to make ammonia in the
converter?
.....................................................................................................................................
.....................................................................................................................................
(2)
(b)
Suggest the purpose of the iron catalyst.
.....................................................................................................................................
.....................................................................................................................................
(1)
(c)
Farmers add ammonium nitrate to the soil. Explain why.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 5 marks)
Q19.
The electron arrangements of calcium and magnesium atoms are shown.
Page 25
(a)
Which group of the Periodic Table contains calcium and magnesium? Give a
reason for your answer.
.....................................................................................................................................
.....................................................................................................................................
(2)
(b)
Small pieces of calcium in cold water move up and down as in the diagram.
(i)
Suggest why the calcium does this.
..........................................................................................................................
..........................................................................................................................
(1)
(ii)
Predict what happens when magnesium is added to cold water.
..........................................................................................................................
..........................................................................................................................
(1)
(c)
Magnesium burns in air to form a white solid. When water is added to the solid a
cloudy alkaline solution of magnesium hydroxide is formed.
(i)
Name the white solid.
..........................................................................................................................
(1)
Page 26
(ii)
Suggest the pH of the magnesium hydroxide solution.
..........................................................................................................................
(1)
(iii)
Why is the solution cloudy?
..........................................................................................................................
(1)
(iv)
Complete the balanced chemical equation for the formation of the magnesium
hydroxide from the white solid.
................................... + H2O → ...................................
(2)
(Total 9 marks)
Q20.
The label shows the ions present in the bottle of spring water. This water is
temporarily hard.
Page 27
(a)
Name the compound that would be present in the greatest amount if this water
were evaporated to dryness.
.....................................................................................................................................
(2)
(b)
(i)
What is hard water?
...........................................................................................................................
...........................................................................................................................
(2)
(ii)
State one advantage of hard water.
...........................................................................................................................
(1)
(c)
Describe an experiment that would show that this water is temporarily hard.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(d)
This hard water may be softened as shown.
Page 28
What name is given to this process?
.....................................................................................................................................
(1)
(Total 10 marks)
Q21.
This question is about the Periodic Table.
(a)
Dimitri Mendeleev was a Russian scientist who, in 1869, helped to develop the
Periodic Table. He made his table with the known elements arranged in order of
increasing atomic mass. He started new rows so that elements with similar chemical
properties would be in the same column. Mendeleev sometimes had to leave gaps
in his table.
(i)
Complete the sentences.
The Periodic Table is now the arrangement of the elements in order
of increasing atomic .......................... . The rows are called ...........................
and the columns are called ....................... .
(3)
Page 29
(ii)
Suggest why Mendeleev had to leave gaps in his table.
...........................................................................................................................
...........................................................................................................................
(1)
(b)
This section of the Periodic Table shows the positions of some elements.
(i)
Give the chemical symbol for one of the noble gases.
...........................................................................................................................
(1)
(ii)
Draw the arrangement of electrons around the nucleus for the noble gas that
you chose in (i).
(1)
(iii)
Why do the electron arrangements of lithium, sodium and potassium make
them react in a similar way?
...........................................................................................................................
...........................................................................................................................
(1)
Page 30
(iv)
Small pieces of lithium, potassium and sodium are added to water.
What is the order of reactivity for these three metals? Put the most reactive
metal first.
...........................................................................................................................
...........................................................................................................................
(1)
(v)
Complete and balance the chemical equation for the reaction of sodium with
water.
2Na(s) + 2H2O(l) → ..........NaOH(aq) + ...............(g)
(2)
(Total 10 marks)
Q22.
Lithium is a very reactive metal.
(a)
Lithium reacts with cold water.
Page 31
(i)
Which physical property of lithium is seen during this reaction?
..........................................................................................................................
(1)
(ii)
Which chemical property of lithium will be shown by the universal indicator?
..........................................................................................................................
(1)
(b)
Complete the sentence by writing in the missing numbers.
Lithium has an atomic number of 3 and a mass number of 7.
This means that an atom of lithium has .................... protons .................... electrons
and ....................... neutrons.
(3)
(Total 5 marks)
Q23.
Chemical tests can be used to identify compounds.
The table shows the results of some tests carried out on three solutions, A, B and C.
Solution
Flame Test
A
Yellow
B
Brick-red
C
Hydrochloric
acid
is added
Sodium
hydroxide
solution
is added
Silver nitrate
solution
is added
Carbon dioxide
gas produced
White precipitate
insoluble in
excess sodium
hydroxide
solution
Dark green
precipitate
Page 32
White
precipitate
Use the information in the table to identify solutions A, B and C.
Give the name of:
(a)
solution A; ...................................................................................................................
(2)
(b)
solution B; ...................................................................................................................
(2)
(c)
the metal ion in solution C. .........................................................................................
(1)
(Total 5 marks)
Q24.
Mendeleev constructed a periodic table in 1869.
In his periodic table:
•
most of the elements were put in order of increasing relative atomic mass;
•
elements with similar properties were put into groups;
•
Mendeleev changed the order of some elements to put them with similar elements;
•
spaces were left for elements that Mendeleev thought would be discovered in the
future.
One space was in Group 3 between the elements aluminium and indium.
Group 3
Boron
Aluminium
?
Indium
Thallium
Mendeleev called this undiscovered element „eka-aluminium‟. This element is now known
as gallium. In 1871, he also predicted some of the properties of gallium.
Page 33
The table shows the properties of aluminium and indium, along with some of the
predictions made by Mendeleev for gallium.
Metal or Boiling Density in
Appearance non-metal point in °C g per cm3
Relative
atomic
mass
Aluminium
silvery white
metal
2467
2.7
27
Predicted properties of
gallium
silvery white
metal
?
?
68
Indium
silvery white
metal
2080
7.31
115
(i)
Suggest two reasons why other scientists in 1871 did not accept Mendeleev‟s
periodic table.
Reason 1 .....................................................................................................................
.....................................................................................................................................
Reason 2 .....................................................................................................................
.....................................................................................................................................
(2)
(ii)
Suggest why the discovery of gallium in 1875 convinced other scientists that
Mendeleev‟s table was correct.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 3 marks)
Q25.
The periodic table on the Data Sheet may help you to answer this question.
(a)
Newlands and Mendeleev both designed periodic tables in which the elements were
put in the order of their relative atomic masses.
When the elements are put in this order a few of them are placed incorrectly when
compared with a modern periodic table.
Page 34
(i)
Give one example of a pair of elements that would be placed incorrectly if
they were in the order of their relative atomic masses.
......................................................... and ..........................................................
(1)
(ii)
Explain why placing these two elements in the order of their relative atomic
masses would not be correct.
...........................................................................................................................
...........................................................................................................................
(1)
(b)
In the modern periodic table the elements are put in order of their atomic (proton)
numbers.
Explain how the positions of the elements in the periodic table are linked to the
electronic structure of their atoms.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)
Q26.
This information has been taken from two bottles of Australian spring water.
Page 35
(a)
The labels show the names of the ions present in Ridgway and Homeland spring
waters.
Describe how these ions got into the water.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(b)
Both Ridgway and Homeland spring waters are hard.
(i)
There are two ions shown on the labels which make these spring waters hard.
Name one of these ions.
...........................................................................................................................
(1)
(ii)
Ridgway spring water is about twice as hard as Homeland spring water.
Use the information on the labels to explain why.
...........................................................................................................................
...........................................................................................................................
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...........................................................................................................................
...........................................................................................................................
(2)
(iii)
Describe how you could use soap solution to show that Ridgway spring water
is about twice as hard as Homeland spring water. You should state how the
experiment is made fair.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(Total 8 marks)
Q27.
Tennis players sometimes use smelling salts to help revive them.
The active chemical in smelling salts is ammonium carbonate, (NH4)2CO3.
Describe how smelling salts can be tested to show that they contain ammonium ions and
carbonate ions. Give the results of the tests.
(a)
Test and result for ammonium ions
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
(b)
Test and result for carbonate ions
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....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
(Total 4 marks)
Q28.
Two problems of hard water are scale and scum, as shown in the pictures of a
heating element and a wash basin.
(a)
Explain the difference between scale and scum
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(b)
Explain how hard water can be made soft using an ion-exchange column.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
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(Total 4 marks)
Q29.
A student burned four fuels and compared the amounts of energy they produced.
The student set up the apparatus as shown in the diagram.
The heat produced when each fuel was burned was used to raise the temperature of 100 g
of water. The student noted the mass of fuel burned, the increase in temperature and
whether the flame was smoky.
The results are shown in the table.
Mass of fuel
burned (g)
Temperature
increase (°C)
Type of
flame
Ethanol
4
24
Not smoky
Methanol
3
9
Not smoky
Peanut oil
2
20
Smoky
Vegetable oil
1
15
Smoky
Fuel
(a)
The student suggested that the vegetable oil was the best fuel for producing heat.
Explain why.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
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.....................................................................................................................................
(2)
(b)
Suggest an environmental problem that could be caused when large amounts of
vegetable oil are burned. Suggest how the problem could be overcome.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(c)
An energy level diagram for the burning of vegetable oil is shown below.
Which of the energy changes A, B or C:
(i)
represents the activation energy
...............................
(1)
(ii)
shows the amount of energy given out during the reaction?
...............................
(1)
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(Total 6 marks)
Q30.
This label has been taken from a packet of My Baby Food.
MY BABY FOOD
Infant milk
Pure and natural
Closest to mothers’ breast milk
Contains traces of essential minerals
500 g
One of the minerals in My Baby Food is calcium carbonate, CaCO3.
(a)
Chemical tests are used to identify elements and compounds.
(i)
A flame test can be used to identify calcium ions.
What colour do calcium ions give in a flame test?
...........................................................................................................................
(1)
(ii)
When a flame test was carried out on My Baby Food, the presence of calcium
ions was not seen. A yellow flame was produced.
Name the ion which gives a yellow flame test.
Page 41
...........................................................................................................................
(1)
(iii)
Suggest one advantage of using an instrumental method to detect the
elements present in My Baby Food.
...........................................................................................................................
...........................................................................................................................
(1)
(iv)
Name an instrumental method for detecting elements.
...........................................................................................................................
(1)
(b)
Read the information in the box below and then answer the question.
Calcium carbonate occurs naturally as marble and limestone. They are
important building materials and are often used for gravestones.
Calcium carbonate is also an essential mineral for good health and is
present in many baby foods in small amounts.
My Baby Food is recommended as being the closest to a mother‟s own
breast milk. It is given free to mothers in the developing world – without it
their babies might die of malnutrition.
Responsible Mothers Are Us (RMAU) is a United Kingdom pressure group.
They want to ban chemicals in baby foods. The group was founded by Mrs
I. M. Right who has made a career in „goodness‟ and is paid from
donations given to RMAU by members of the public.
When interviewed, she said: “Calcium carbonate is a chemical and so it is
a pollutant. My Baby Food must be banned to prevent the mass medication
of babies. I don‟t feed my baby the stuff of gravestones.”
Many people do not agree with Mrs Right‟s ideas.
Suggest why.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
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.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 7 marks)
Q31.
Chlorine and bromine are important Group 7 elements.
(a)
Explain why chlorine is added to drinking water.
.....................................................................................................................................
.....................................................................................................................................
(1)
(b)
Describe what you would see when bromine water is added to an unsaturated
organic compound.
.....................................................................................................................................
.....................................................................................................................................
(1)
(c)
Bromine can be extracted from seawater. The dissolved bromide ions are reacted
with chlorine. Bromine and chloride ions are formed.
(i)
Complete and balance the equation below, which represents the reaction
between chlorine and bromide ions.
Cl2 + 2Br– → ......................... + .........................
(1)
(ii)
Describe what you see when chlorine is added to a solution containing
bromide ions.
...........................................................................................................................
...........................................................................................................................
(1)
(d)
In terms of electronic structure:
Page 43
(i)
state why bromine and chlorine are both in Group 7
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
explain why bromine is less reactive than chlorine.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(e)
What is the result of adding acidified silver nitrate solution to a solution containing:
(i)
chloride ions
...........................................................................................................................
(1)
(ii)
bromide ions?
...........................................................................................................................
(1)
(Total 10 marks)
Q32.
Ammonium nitrate is an important chemical. The diagram shows the main stages in
the manufacture of ammonium nitrate.
Study the diagram and then answer the question.
Page 44
(a)
What is the purpose of the iron in reactor 1?
.....................................................................................................................................
.....................................................................................................................................
(1)
(b)
Explain why the best yield of ammonia at equilibrium is obtained:
(i)
at low temperature
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
at high pressure.
...........................................................................................................................
...........................................................................................................................
(1)
(c)
The temperature used in reactor 1 is 450 °C.
Page 45
Explain why a much lower temperature is not used.
.....................................................................................................................................
.....................................................................................................................................
(1)
(d)
A mixture of ammonia, nitrogen and hydrogen leaves reactor 1.
In the separator, what is done to the mixture to separate the ammonia from the
other gases?
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 5 marks)
Q33.
In some parts of the world the water is hard, but in other parts the water is soft.
(i)
Name an ion that causes water to be hard.
.....................................................................................................................................
(1)
(ii)
Describe how these ions get into the water.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(iii)
Sodium carbonate makes hard water soft.
Explain how.
.....................................................................................................................................
.....................................................................................................................................
Page 46
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 5 marks)
Q34.
Read the information about energy changes and then answer the questions.
A student did an experiment to find the energy change when hydrochloric acid
reacts with sodium hydroxide. The equation which represents the reaction is:
HCl + NaOH → NaCl + H2O
The student used the apparatus shown in the diagram.
The student placed 50 cm3 of hydrochloric acid in a glass beaker and measured the
temperature.
The student then quickly added 50 cm3 of sodium hydroxide solution and stirred
the mixture with the thermometer. The highest temperature was recorded.
The student repeated the experiment, and calculated the temperature change each
time.
(a)
The biggest error in this experiment is heat loss.
Page 47
Suggest how the apparatus could be modified to reduce heat loss.
.....................................................................................................................................
.....................................................................................................................................
(1)
(b)
Suggest why it is important to stir the chemicals thoroughly.
.....................................................................................................................................
(1)
(c)
Which one of these experiments was probably carried out on a different day to the
others?
Explain your answer.
.....................................................................................................................................
.....................................................................................................................................
(1)
(d)
Suggest why experiment 4 should not be used to calculate the average
temperature change.
.....................................................................................................................................
.....................................................................................................................................
(1)
(e)
Calculate the average temperature change from the first three experiments.
.....................................................................................................................................
Answer = .............................. °C
(1)
(f)
Use the following equation to calculate the energy change for this reaction.
energy change in joules = 100 × 4.2 × average temperature change
.....................................................................................................................................
Answer = .............................. J
(1)
Page 48
(g)
Which one of these energy level diagrams, A or B, represents the energy change
for this reaction?
Explain why.
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 7 marks)
Q35.
Read the information about energy changes and then answer the questions.
A student did an experiment to find the energy change when hydrochloric acid
reacts with sodium hydroxide. The equation which represents the reaction is:
HCl + NaOH → NaCl + H2O
The student used the apparatus shown in the diagram.
The student placed 50 cm3 of hydrochloric acid in a glass beaker and measured the
temperature.
The student then quickly added 50 cm3 of sodium hydroxide solution and stirred
the mixture with the thermometer. The highest temperature was recorded.
Page 49
The student repeated the experiment, and calculated the temperature change each
time.
(a)
The biggest error in this experiment is heat loss.
Suggest how the apparatus could be modified to reduce heat loss.
.....................................................................................................................................
.....................................................................................................................................
(1)
(b)
Suggest why it is important to stir the chemicals thoroughly.
.....................................................................................................................................
(1)
(c)
Which one of these experiments was probably carried out on a different day to the
others?
Explain your answer.
.....................................................................................................................................
.....................................................................................................................................
(1)
(d)
Suggest why experiment 4 should not be used to calculate the average
temperature change.
.....................................................................................................................................
.....................................................................................................................................
(1)
Page 50
(e)
Calculate the average temperature change from the first three experiments.
.....................................................................................................................................
Answer = .............................. °C
(1)
(f)
Use the following equation to calculate the energy change for this reaction.
energy change in joules = 100 × 4.2 × average temperature change
.....................................................................................................................................
Answer = .............................. J
(1)
(g)
Which one of these energy level diagrams, A or B, represents the energy change
for this reaction?
Explain why.
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 7 marks)
Page 51