2013 Senior External Examination
Chemistry
Monday 4 November 2013
Paper One — Question and response book
Time allowed
• Perusal time: 10 minutes
• Working time: 2 hours 30 minutes
9 am to 11:40 am
Candidate use
Print your candidate number here
1 3 –
Examination materials provided
• Paper One — Question and response book
• Paper One Part A — Multiple-choice response sheet
• Paper One — Resource book
Attach barcode here
Equipment allowed
• QSA-approved equipment
• non-programmable calculator
Directions
Do not write in this book during perusal time.
Paper One has two parts:
• Part A — Knowledge of subject matter:
Section 1 — Multiple choice (attempt all questions)
Section 2 — Short response (attempt all questions)
• Part B — Scientific processes (attempt four questions only)
Suggested time allocation
• Part A: 1 hour 50 minutes
• Part B: 40 minutes
Assessment
Paper One assesses the following assessment criteria:
• Knowledge of subject matter
• Scientific processes
Assessment standards are at the end of this book.
After the examination session
The supervisor will collect this book when you leave.
Number of books used
Supervisor use only
Supervisor’s initials
QSA use only
Marker number
–
Planning space
Part A — Knowledge of subject matter
Part A assesses knowledge of subject matter and its simple application based on the topics in
the Chemistry Senior External Syllabus 1998 (amended 2006).
Part A is worth 80 marks.
Suggested time allocation: 1 hour 50 minutes.
Section 1 — Multiple choice
Section 1 has 10 questions of equal value. Attempt all questions.
Each question contains four options. Select the option that you think is correct or is the best
option. Respond on the multiple-choice response sheet.
Question 1
Which of the following pairs represent isotopes of the fictitious element Z?
A
84
36Z
and
84
30Z
B
54
26Z
and
56
26Z
C
10
5Z
and
20
10Z
D
1
1Z
and
1
2Z
Question 2
Ammonium acetate has the formula CH3 CO2 NH4 . From this it can be concluded that
A
there are twelve atoms per formula unit.
B
there are six different elements in the compound.
C
carbon makes up 2/12 of the mass of the compound.
D
the compound is very reactive because of the presence of the seven H atoms.
Question 3
A compound which melts at 815 °C and does not conduct electricity as a solid but does so when
dissolved in water could be composed of
A
ions in a three dimensional lattice.
B
atoms held together by covalent bonds.
C
molecules in a three dimensional lattice.
D
molecules held together by hydrogen bonds.
2013 Chemistry — Paper One — Question and response book
1
Question 4
1.0 g of hydrogen gas is reacted with 10.0 g of oxygen gas in a closed container. When the reaction is
complete, the mass of substances in the container is
A
1.0 g.
B
8.0 g.
C
9.0 g.
D
11.0 g.
Question 5
Fluorine reacts spontaneously with bromide ions according to the following equation:
F 2  g  + 2Br –  aq   2F – aq  + Br 2  g 
Which of the following is the strongest oxidising agent?
A
F2 (g)
B
Br – (aq)
C
F – (aq)
D
Br2 (g)
Question 6
Which of the following molecules is a structural isomer of propanoic acid?
A
H H H O
H C C C C OH
H H H
B
H H O
HO
C C C OH
H H
C
H H H
O C C C O
H
D
H
HO C C C OH
H H H
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2013 Chemistry — Paper One — Question and response book
Question 7
A section of the periodic table has had the chemical symbols replaced by letters.
K
L
M
N
The element which belongs to the d block of the periodic table is
A
K.
B
L.
C
M.
D
N.
Question 8
A sample of gas is held in a closed container at a temperature of 10 °C. What final temperature would
be required in order for the average kinetic energy of the particles to be doubled?
A
20 °C
B
120 °C
C
283 °C
D
293 °C
Question 9
An accurate description of a 6M solution of CH3 COOH (acetic acid) of Ka = 1.8 x 10– 5
would be a
A
dilute weakly acidic solution.
B
dilute strongly acidic solution.
C
concentrated weakly acidic solution.
D
concentrated strongly acidic solution.
2013 Chemistry — Paper One — Question and response book
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Question 10
During the progress of a chemical reaction,
A
most collisions involve only two particles.
B
a successful collision is one in which the reactants are formed again.
C
the activated complex has a lower energy than either reactants or products.
D
the rate can be determined by an inspection of the relevant chemical equation.
End of Section 1
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2013 Chemistry — Paper One — Question and response book
Section 2 — Short response
Section 2 has eight questions. Attempt all questions.
Write your responses in the spaces provided. Show all working.
If you need more space for a response, continue on page 26 of this book.
Label any continued response with the question number.
Question 11 — Materials: Properties, bonding and structure
a.
An atom of an element contains 18 neutrons and 17 electrons.
i.
What is the atomic number?
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(½ mark)
ii. What is the mass number?
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(½ mark)
b.
List the type of attractive force that is overcome when each of the following substances melt.
Substance
Force
Copper
Copper sulfate
Ice
Diamond
(2 marks)
c.
Give the formula for the sulfate ion.
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(½ mark)
d.
Name the substance represented by the formula Mg(OH)2 .
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(1 mark)
2013 Chemistry — Paper One — Question and response book
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e.
For each pair listed below, state an experimental test that could be used to distinguish between the
two. How would the results differ for each test?
Pure water/Solution of
sodium chloride in water
Test:
Iron sulfide/Mixture of
iron and sulfur
Test:
Results:
Results:
(3 marks)
f.
Draw Lewis diagrams for the following molecules and give the shape of each molecule.
.
Molecule
Lewis diagram
Shape of molecule
CH4
NCl3
(2 marks)
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2013 Chemistry — Paper One — Question and response book
Question 12 — Reacting quantities and chemical analysis
a.
Define the following terms:
i.
Avogadro’s number
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(1 mark)
ii. relative atomic mass
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(1 mark)
b.
Balance the following equation.
.
HCl(aq) +
Fe2 O3 (s) 
FeCl3 (s) +
H2 O(l)
(2 marks)
c.
Calculate:
i.
the mass, in grams, of one molecule of H2 S.
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(1 mark)
ii. the number of hydrogen atoms in five molecules of CH3 COOH.
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(1 mark)
iii. the concentration (molarity) of the nitrate ions in an aqueous solution which contains
45.0 g of dissolved aluminium nitrate in a volume of 800.0 mL.
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(2½ marks)
2013 Chemistry — Paper One — Question and response book
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d.
Octane  C 8 H 18  g   burns in oxygen to produce carbon dioxide gas and water vapour.
What is the change in the total number of moles between reactants and products when 57 g of
octane burns completely?
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(2½ marks)
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2013 Chemistry — Paper One — Question and response book
Question 13 — Oxidation and reduction
a.
Explain the meaning of the following terms:
i.
electrolytic cell
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(1 mark)
ii. oxidising agent (oxidant)
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(1 mark)
b.
Does the following equation represent an oxidation–reduction reaction? Explain your reasoning.
2Al  s  + Fe 2 O 3 s   Al 2 O 3 s  + 2Fe  s 
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(1 mark)
c.
Will a reaction occur spontaneously when a piece of solid copper is placed in a 1.0M Pb2 + (aq)
solution? Explain your reasoning.
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(2 marks)
2013 Chemistry — Paper One — Question and response book
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d.
An electrochemical cell is constructed using:
• two beakers
• 1.0M solutions of Fe2+ and Pb2 +
• clean pieces of Fe and Pb
• a piece of porous paper which had been soaked in a KNO3 solution
• a voltmeter
• connecting wires.
Use the table of standard reduction potentials for half-reactions in the resource book to draw a
diagram of the electrochemical cell described above, correctly labelling the:
• anode and cathode
• electron flow direction
• nature and direction of the flow of ions
• charge on each electrode.
(3 marks)
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2013 Chemistry — Paper One — Question and response book
Question 14 — Organic chemistry
a.
Complete the following table.
.
General formula
Structure which contains
three carbon atoms
alkenes
ketones
(2 marks)
b.
Draw the structure of methyl butanoate.
(1 mark)
c.
Name the organic substance with the following structure.
CH3
CH2
H 3C C
CH2 CH3
CH2
CH2
CH2 CH2
CH3
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(1 mark)
d.
What would be the product/s of the following chemical changes?
uv radiation
i. CH 4  g  + Br 2  1 
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(1 mark)
–
+
ii. C 2 H 5 OH  1  + MnO 4  aq  + H  aq 
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(1 mark)
e.
An organic compound is either an aldehyde or a ketone. List a test and subsequent results that
could be used to identify the compound.
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(2 marks)
2013 Chemistry — Paper One — Question and response book
11
Question 15 — Chemical periodicity
a.
State the trends in the periodic table for the following:
i.
first ionisation energy of the group 2 elements
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(½ mark)
ii. atomic radius of the period 3 elements
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(½ mark)
b.
Write the electron configuration for an aluminium atom.
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(1 mark)
c.
The first six ionisation energies of the nitrogen atom, in kJ mol–1 , are listed in the following table.
E1
1400
E2
2850
E3
4560
E4
7450
E5
9460
E6
53 100
Explain why:
i.
E6 is much greater than E5
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(1 mark)
ii. the first ionisation energy (E1 ) for C (1086 kJ mol–1 ) is less than E1 for
N (1400 kJ mol– 1 ).
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(1 mark)
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2013 Chemistry — Paper One — Question and response book
d.
Consider the elements lithium and fluorine from the second period of the periodic table and the
elements potassium and bromine from the fourth period.
Explain why:
i.
potassium is more reactive than lithium
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ii. bromine is less reactive than fluorine.
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(2 marks)
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Question 16 — Gases and the atmosphere
a.
Describe a factor which affects the concentration of ozone in the upper atmosphere.
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(1 mark)
b.
List one major gas in the earth’s atmosphere and describe how it affects human welfare.
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(1 mark)
c.
What is the normal boiling point of a substance whose vapour pressure varies as shown in the
graph below?
200
175
150
Vapour pressure
(kPa)
125
100
75
50
25
0
50
60
70
80
Temp (°C)
90
100
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(1 mark)
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2013 Chemistry — Paper One — Question and response book
d.
Consider the two bulbs below.
Bulb A
Bulb B
He
pressure = 1.5 atm
volume = 1 L
Ne
pressure = 1.0 atm
volume = 2 L
negligible
volume in
the valve
The valve is opened and the contents of the bulbs are allowed to mix, with the temperature being
kept constant.
What is the final pressure of the gas mixture?
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(3 marks)
2013 Chemistry — Paper One — Question and response book
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Question 17 — Energy and rates of chemical reactions
a.
Define the following terms:
i.
catalyst
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(1 mark)
ii. activated complex
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(1 mark)
b.
State the basic postulates of the collision theory of reactions.
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(2 marks)
c.
Given the following data,
S  s  + 1 1--2- O 2  g   SO 3  g 
H = – 395.2 kJ
2SO 2  g  + O 2  g   2SO 3  g 
H = – 198.2 kJ
calculate H for the reaction below.
S  s  + O 2 g   SO 2 g 
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(2 marks)
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2013 Chemistry — Paper One — Question and response book
d.
The following energy diagram shows the energy change in kJ mol– 1 associated with the use of
glucose (C6 H1 2 O6 ) in body processes.
180 kJ mol–1
Energy
(kJ mol–1)
300 kJ mol–1
reactants
products
Reaction coordinate
i.
Is the reaction exothermic or endothermic? Explain why.
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(1 mark)
ii. Calculate the energy change per gram of glucose.
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(1 mark)
2013 Chemistry — Paper One — Question and response book
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Question 18 — Chemical equilibrium
a.
Define pH.
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(1 mark)
b.
Complete the following table.
Term
Description
Example
Weak electrolyte
(1½ marks)
c.
A dynamic equilibrium is:
i. recognised by
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ii. explained by
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(1 mark)
d.
An equilibrium mixture is established by the addition of concentrated hydrochloric acid to a
concentrated solution of cobalt chloride according to the following equation.
Co  H 2O  6
2+
–0
 aq  + 4Cl 0  aq 
(red)
i.
2–
CoCl 4
 aq  + 6H 2 O  1 
(blue)
Write the equilibrium law expression.
(1 mark)
ii. Explain why the mixture becomes more blue when it is warmed.
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(1 mark)
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2013 Chemistry — Paper One — Question and response book
e.
Find the pH of the solution which results when 25.0 mL of 0.12M NaOH is added to 50.0 mL of
0.17M HCl.
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(4 marks)
f.
10.0 mL of 0.25M Mg(NO3 )2 solution is mixed with 25.0 mL of 0.20M NaF solution.
–8
Will a precipitate form?  K sp for MgF 2 = 8  10 
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(4 marks)
End of Section 2
End of Part A
2013 Chemistry — Paper One — Question and response book
19
Part B — Scientific processes
Part B assesses scientific processes based on the topics in the Chemistry Senior External
Syllabus 1998 (amended 2006) and practical work undertaken during your study of the subject.
Part B has five questions of equal value. Attempt four questions only. If you respond to all five
questions, only your first four responses will be assessed.
Write your responses in the spaces provided.
Suggested time allocation: 40 minutes.
Question 1 — Chemical periodicity
The following information concerning five consecutive elements in the periodic table was collected.
The letters assigned to the elements do not show the group order.
Elements
Properties
A
• reacts vigorously with water to liberate a gas which ignites and burns
B
• is very unreactive
• is a monatomic gas sometimes used in light bulbs
C
• exists as a gas (composed of diatomic molecules) at room temperature
• reacts with element A to form a stable solid compound AC
D
• reacts with element C to form the compound DC2
• has a higher boiling point than A
• is a good conductor of electricity
• reacts slowly with water
E
• exists as a solid at room temperature
• reacts with D to form the compound ED
• burns in air to form a gas with the formula EO2 (O = oxygen)
Determine the group of the periodic table to which each element belongs. You must justify your
choices.
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2013 Chemistry — Paper One — Question and response book
Question 2 — Oxidation and reduction
A student set up an experiment using strips of four different metals (J, L, M and N) which were placed
in four different solutions that contained J2 + , L2 + , M2+ and N2 + ions respectively (16 beakers in all).
The following results were obtained:
• metal L remained unchanged in all four solutions
• metal M was coated with another substance when placed in solutions of J2 + and L2 + only
• metal N was coated with another substance when placed in solutions of J2 + , L2 + and M2 + .
Which pair of half-reactions would produce the greatest potential difference in an electrochemical
cell?
Show all working to explain your choice and include all the appropriate half-equations.
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Question 3 — Organic chemistry
An organic compound, “W”:
• has a molar mass of 42.0 g
• burns in pure oxygen to produce carbon dioxide and water only
• reacts with an equimolar amount of hydrogen bromide to form compound “X” only.
Compound “X” reacts with sodium hydroxide solution to form compound “Y”.
Compound “Y” reacts with ethanoic acid (C2 H4 O2 ) in the presence of a suitable catalyst to form
compound “Z” and water.
Determine the molecular formulas for compounds “W”, “X”, “Y” and “Z”. Explain the choices you
made.
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2013 Chemistry — Paper One — Question and response book
Question 4 — Materials: Properties, bonding and structure
A scientist was given unknown pure substances labelled A, B, C and D. She obtained the information
below from research and experimentation to develop element profiles.
Features
Appearance
A
C
D
pale green colour
shiny
shiny
Solubility in water nil
slightly soluble
nil
nil
Change on heating produces a white
in a Bunsen flame solid
no change
produces a black
solid
no change
Melting point °C
842
–101
1085
1200
Combine with
acid
generates a large
amount of heat
slight colour
change
generates heat,
colour change
no reaction
Periodic table
group
2
17
unknown
unknown
Electrical
conductivity
good
non-conductor
good
good
Tensile strength
high
nil
moderate
high
a.
shiny
B
Use the information from the table to identify one chemical property and one physical property.
Chemical:
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Physical:
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b.
Substances A and B react together to form compound X.
Is the bonding in compound X ionic or covalent? Justify your choice.
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c.
Is substance C a metal or a non-metal? Explain your choice.
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d.
Based on the information in the table, which material would be most suitable for making a scuba
diving tank? Justify your choice.
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2013 Chemistry — Paper One — Question and response book
23
Question 5 — Energy and rates of chemical reactions
While researching energy values of fuels, a student designed an experiment to determine the heat of
combustion using the apparatus below.
Hexane (C6 H1 4 ) of actual heat value (4160 kJ mol– 1 ) was first used in the burner. Pentane (C5 H1 2 )
was then substituted for the hexane and all other conditions kept constant.
thermometer
beaker
clamp
100 ml of H2O
flame
cloth wick
fuel
glass bulb
Burning hexane
Initial water temperature
(°C)
Final water temperature
(°C)
Mass of hexane burned
(g)
20.0
70.0
0.50
Burning pentane
Initial water temperature
(°C)
Final water temperature
(°C)
Mass of pentane burned
(g)
19.0
68.0
0.43
Find the actual heat of combustion of pentane, to the highest degree of accuracy available, with due
consideration of the information gathered from the hexane investigation.
Consider experimental design and the associated errors in addition to the application of numerical
calculations.
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2013 Chemistry — Paper One — Question and response book
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End of Part B
End of Paper One
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2013 Chemistry — Paper One — Question and response book
2013 Chemistry — Paper One — Question and response book
27
Very High Achievement
Scientific
processes
A very high ability to succeed in
simple scientific process tasks —
collecting and organising data,
processing information, making
simple judgments,
communicating information in
various contexts, devising and
designing simple and/or singlestep investigations.
Knowledge of A very high ability to recall and
subject
apply knowledge of chemistry in
matter
simple situations.
Criteria
Sound Achievement
A high ability to succeed in
simple scientific process tasks —
collecting and organising data,
processing information, making
simple judgments,
communicating information in
various contexts, devising and
designing simple and/or singlestep investigations.
Very Limited Achievement
Very limited ability to succeed in
simple scientific process tasks.
Limited ability to recall and apply Very limited ability to recall and
knowledge of chemistry in simple apply knowledge of chemistry in
situations.
simple situations.
Limited Achievement
A satisfactory ability to succeed Limited ability to succeed in
in simple scientific process tasks simple scientific process tasks.
— collecting and organising data,
processing information, making
simple judgments,
communicating information in
various contexts, devising and
designing simple and/or singlestep investigations.
A high ability to recall and apply A satisfactory ability to recall and
knowledge of chemistry in simple apply knowledge of chemistry in
situations.
simple situations.
High Achievement
Paper One
Assessment standards from the Chemistry Senior External Syllabus 1998 (amended 2006)
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