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Chemistry Advanced Level Paper 3 (9CH0/03)
Question
Number Acceptable Answer Additional Guidance Mark
1(a)(i) suitable scale and axes labelled including units (1)
all points plotted correctly (1)
line of best fit (1)
Plotted points use at least half the available space in
both directions
±½ a square
Smooth line, no dot to dot NOTE: Points at t = 2000 and 6000 s should not be on
the line of best fit. 3
CHERRY HILL TUITION EDEXCEL CHEMISTRY A2 PAPER 32 MARK SCHEME
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Question
Number Acceptable Answer Additional Guidance Mark
1(a)(ii) 1st order with respect to SO2Cl2 as half-life is constant
(1)
values of two half-lives shown in graph in range 2000 –
2400 (s) (1)
rate = k[SO2Cl2] (1)
Example of graph
3
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(Total for Question 1 = 12 marks)
Question
Number Acceptable Answer Additional Guidance Mark
1(a)(iii)
tangent drawn at 0.200 mol dm-3 SO2Cl2 (1)
value of gradient (1)
k = rate / 0.200 (1)
value of k to 2 or 3 SF and units (1)
Example of calculation
e.g. gradient = (-) 0.375/6400 = (-) 5.859 x 10−5
must be consistent with tangent shown on graph
k = 5.859 x 10−5/ 0.200
= 2.9 x 10−4 s−1 / 2.93 x 10−4 s−1
Allow TE from incorrect rate equation / allow TE from
incorrect gradient Units must be consistent with rate equation
4
Question
Number Acceptable Answer Additional Guidance Mark
1 (b) RDS Step 1 SO2Cl2 → SO2Cl + Cl (1)
Step 2 SO2Cl + Cl → SO2 + Cl2 (1)
The RDS must involve one mol of SO2Cl2
The equations taken together must add up to the overall equation SO2Cl2 → SO2 + Cl2
e.g. SO2Cl2 → SO2 + 2Cl
2Cl → Cl2
Ignore state symbols
2
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Question Number
Acceptable Answer Additional Guidance Mark
2(a)
mass of C (1)
mass of H (1)
mass of oxygen
and mols of C, H and O (1)
ratio (1)
empirical and use of molar mass to determine molecular formula
(1)
Example of calculation
mass of C = 2.83 x 12/44 = 0.772 g
mass of H = 0.693 x 2/18 = 0.077 g
mass of oxygen = 0.952 – (0.772 + 0.077) = 0.103 g
C H O
Moles 0.772/12=0.0643 0.077/1=0.077 0.103/16=0.0064
ratio 0.0643/0.0063=10 0.077/0.00643=12 0.0064/0.0064=1
Empirical formula = C10H12O, this has mass =148
so molecular formula = C10H12O
5
Question
Number Acceptable Answer Additional Guidance Mark
2(b)(i) An answer that makes reference to the following point:
contains benzene ring / arene
Ignore comments about alkenes / unsaturated 1
Question Number
Acceptable Answer Additional Guidance Mark
2(b)(ii) is an aldehyde or ketone / is a
carbonyl compound
Both aldehyde and ketone required for first alternative 1
Question Number
Acceptable Answer Additional Guidance Mark
2(b)(iii) (Q is a) ketone Allow ‘not an aldehyde’ if first alternative given in
(b)(ii)
1
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Question
Number Acceptable Answer Additional Guidance Mark
2(c) An answer that makes reference to the following points:
(2)
Chemical shift (1)
peak at 7.5 ppm indicates a benzene ring and peak at 2.55
ppm indicates H on carbon adjacent to C=O and peak at 1.25
ppm indicates alkyl hydrogens
Splitting pattern (2)
Any 2 from 3:
complex multiplet indicates a benzene ring
septuplet indicates 6 equivalent protons on adjacent carbons
doublet indicates one hydrogen on adjacent carbon
Area under peak (2)
Any 2 from 3:
five H’s indicate C6H5 / monosubstituted benzene ring
one H indicates one H on C next to carbonyl group
six H’s indicates six H’s on two methyl groups
Award 1 mark for any structure of C10H12O which
includes a benzene ring and a ketone
e.g.
7
(Total for Question 2 = 15 marks)
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Question
Number Acceptable Answer Additional Guidance Mark
3(a) (i) An answer that makes reference to the following points:
EITHER the solution of manganate(VII) ions (1)
as distilled water/other solutions remaining in burette will dilute
the solution of manganate(VII) ions (1)
OR Distilled water, followed by the solution of manganate(VII) ions
(1)
So the distilled water will not dilute the solution of
manganate(VII) ions (1)
2
Question Number
Acceptable Answer Additional Guidance Mark
3(a) (ii) An answer that makes reference to the following points:
measure from the bottom of the meniscus (of the solution of
manganate(VII) ions) (1)
with eyes / head at same level (as meniscus)
or ensuring the burette is vertical
or use of white background to emphasise meniscus
or ensuring funnel is removed from top of burette
or ensuring there is no air bubble in the tip of the burette
(1)
2
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Question
Number Acceptable Answer Additional Guidance Mark
3(a) (iii) An explanation that makes reference to the following point:
it will not change the amount / moles (of reactants) in the flask
1
Question
Number Acceptable Answer Additional Guidance Mark
3(b) H2C2O4 → 2CO2 + 2H+ + 2e− / C2O4
2- → 2CO2 + 2e−
and
MnO4− + 8H+ + 5e− → Mn2+ + 4H2O (1)
5H2C2O4 + 2MnO4− + 6H+ → 2Mn2+ + 10CO2 + 8H2O / 5C2O4
2- +
2MnO4− + 16H+ → 2Mn2+ + 10CO2 + 8H2O
(2)
Ignore state symbols
Allow for 1 mark: 5H2C2O4 + 2MnO4
− + 16H+ → 2Mn2+ + 10CO2
+ 8H2O + 10H+
3
Question
Number Acceptable Answer Additional Guidance Mark
3(c) mean = 22.7 / 22.70 (cm3) (1)
1
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Question
Number Acceptable Answer Additional Guidance Mark
3(d)
calculates amount of MnO4− (1)
calculates amount of H2C2O4 (in 25 cm3) (1)
calculates amount of H2C2O4 (in 250 cm3) (1)
calculates relative molecular mass of acid (1)
calculates x (1)
Example of calculation
Amount of MnO4− = 22.7/1000 x 0.0105 =
2.3835 x 10−4 mol
TE on mean in (c)
Amount of H2C2O4 (in 25 cm3)
= 2.3835 x 10−4 x 2.5 = 5.95875 x 10−4 mol
TE on mol ratio in equation in (b)
Amount of H2C2O4 (in 250 cm3)
= 5.95875 x 10−4 x 10 = 5.95875 x 10−3 mol
Relative molecular mass of acid
= 0.747 / 5.95875 x 10−3 = 125.4
So relative mass of water of
crystallisation = 125.4 – 90 = 35.4
35.4/18 = 1.97 so x = 2
Do not award x = 1.97
5
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Question Number
Acceptable Answer Additional Guidance Mark
3 (e) An answer that makes reference to the following point:
more MnO4− would show greater amount of H2C2O4 (1)
so molecular mass of xH2O would seem to be less, so value for x
would be less (1)
or
more MnO4− means lower molecular mass (1)
therefore mass of water of crystallisation is less so x is less than
2 (1)
2
(Total for Question 3 = 16 marks)
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Question
Number Acceptable Answer Additional Guidance Mark
4 (a) An explanation that makes reference to the following point:
production of CO2 (1)
NaHCO3 + HCl → NaCl + CO2 + H2O (1)
Allow HCO3
− + H+ → CO2 + H2O
Ignore state symbols
2
Question Number
Acceptable Answer Additional Guidance Mark
4 (b) An answer that makes reference to the following points:
drying agent (1)
mixture becomes transparent / clear (from cloudy) (1)
Allow to remove water
Allow drying agent stops clumping together
2
Question
Number Acceptable Answer Additional Guidance Mark
4 (c) An explanation that makes reference to the following points:
they will reduce the yield (1)
as some of the 2-chloro-2-methylpropane will react with the water (and reform the alcohol) (1)
Allow ‘as some of the 2-chloro-2-methylpropane might dissolve in the water’
2
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Question Number
Acceptable Answer Additional Guidance Mark
4(d)
breaking of CO bond in protonated alcohol (1)
structure of intermediate (1)
correct charge on carbon in intermediate (1)
attack of chloride ion with lone pair (1)
Arrow must originate from bond and finish on oxygen
Arrow must originate from lone pair on Cl−
4
(Total for Question 4 = 10 marks)
CHERRY HILL TUITION EDEXCEL CHEMISTRY A2 PAPER 32 MARK SCHEME
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Question
Number Acceptable Answer Additional Guidance Mark
*5 (a) This question assesses a student’s ability to show a coherent and logically
structured answer with linkages and fully-sustained reasoning.
Marks are awarded for indicative content and for how the answer is
structured and shows lines of reasoning.
The following table shows how the marks should be awarded for indicative content.
Number of
indicative marking
points seen in answer
Number of
marks awarded for indicative
marking points
6 4
5–4 3
3–2 2
1 1
0 0
The following table shows how the marks should be awarded for structure and lines of reasoning.
Number of marks awarded for
structure of answer and sustained line of reasoning
Answer shows a coherent and logical
structure with linkages and fully sustained lines of reasoning
demonstrated throughout
2
Answer is partially structured with some linkages and lines of reasoning
1
Answer has no linkages between
points and is unstructured 0
Guidance on how the mark scheme should
be applied:
The mark for indicative content should be added to the mark for lines of reasoning.
For example, an answer with five indicative marking points which is partially structured
with some linkages and lines of reasoning scores 4 marks (3 marks for indicative
content and 1 mark for partial structure and some linkages and lines of reasoning).
If there are no linkages between points,
the same five indicative marking points would yield an overall score of 3 marks (3
marks for indicative content and no marks for linkages).
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Indicative Content:
technique A allows heating for a longer time period / technique B is suitable for a shorter time period
technique A ensures oxidation / technique B may result in loss of reactant before oxidation
technique A minimises release of flammable or harmful vapours / technique B allows release of flammable or harmful vapours, unless
carried out in fume cupboard
technique A involves more expensive equipment or is more complex
to set up / technique B is simpler to set up or uses less expensive
equipment
as complete oxidation is not necessary to qualitatively show it is an
alcohol that can be oxidised
technique B is most appropriate as simpler / technique A is most
appropriate as oxidation is guaranteed
6
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Question Number
Acceptable Answer Additional Guidance Mark
5 (b) An explanation that makes reference to the following pairs:
either
no, as chloride ions could be oxidised by dichromate(VI) ions (reducing amount of oxidant / producing toxic chlorine) (1)
Eo values for dichromate(VI) and chloride ions being oxidised to chlorine are sufficiently close (even though Eo is negative
= -0.03 V) for chlorine to be formed (1)
or
yes, as reaction is dependent on H+ ions (not anions) (1)
Eo value is negative (-0.03 V) (1)
2
Question
Number Acceptable Answer Additional Guidance Mark
5 (c)
1
(Total for Question 5 = 9 marks
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Question
Number Acceptable Answer Additional Guidance Mark
6 (a) suitable extrapolation (1)
∆T in the range of 29 – 33(oC) (1)
Vertical at 3 minutes and smooth curve of best fit
back from 10 minutes to 3 minutes
2
Question Number
Acceptable Answer Additional Guidance Mark
6 (b) (i) An explanation that makes reference to the following point:
as reaction is not instantaneous / takes time to release
heat (1)
so some heat is lost as mixture heats up (1)
2
CHERRY HILL TUITION EDEXCEL CHEMISTRY A2 PAPER 32 MARK SCHEME
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Question
Number Acceptable Answer Additional Guidance Mark
6 (b) (ii) An explanation that makes reference to the following points:
by using more finely powdered zinc (1)
because it will increase the rate of reaction (1)
A greater surface area of zinc
Less time for heat loss
2
Question Number
Acceptable Answer Additional Guidance Mark
6 (c) Calculation of Q using Q = mc∆T (1)
amount of CuSO4(aq) (1)
energy per mol = Q/0.018 (1)
∆H = -Q/1000 kJ mol−1 (1)
Using ∆T from (a)
Example of calculation 25 x 4.18 x 30.5 = 3 187 (J)
Allow 4.2 for 4.18
= 25/1000 x 0.720 = 0.018
3 187/0.018
= −177 kJ mol−1 / −180 kJ mol−1 / −177 000 J mol−1 / −180 000 J mol−1
Use of 4.2 gives −178 kJ mol−1
Must have correct sign and units for 4th mark
4
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Question
Number Acceptable Answer Additional Guidance Mark
6 (d) (i) (217 – answer to (c) / 217) x 100
Example of calculation
(217 – 177 / 217) x 100 = 18.4%
1
Question
Number Acceptable Answer Additional Guidance Mark
6 (d) (ii) An answer that makes reference to two of the following points:
no lid is used (1)
SHC of solution may not be 4.18 (1)
energy absorbed by zinc / energy absorbed by thermometer / polystyrene cup (1)
mass of solution is greater than 25 grams (1)
If answer in (c) is less negative than -217, points
one and three are valid, and for point two
candidates must state less than 4.18 for SHC
If answer in (c) is more negative than -217, only point two can be awarded for candidates stating
SHC is greater than 4.18
Do not award marks for just ‘heat loss to surroundings’
2
Question
Number Acceptable Answer Additional Guidance Mark
6 (d) (iii) An explanation that makes reference to the following points:
∆T would be less, so ∆rH / enthalpy change calculated would be less negative (1)
because heat energy is transferred to greater volume of
water than expected volume (1)
2
(Total for question 6 = 15 marks)
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Question
Number Acceptable Answer Additional Guidance Mark
7 (a) +5 1
Question
Number Acceptable Answer Additional Guidance Mark
7 (b) (i) choice of suitable reducing agent
From Data Booklet of the standard electrode potentials, the right hand substance in numbers 16-
24
1
Question Number
Acceptable Answer Additional Guidance Mark
7 (b) (ii) An answer that makes reference to the following point:
may be kinetically hindered
or
activation energy may be too high
Allow reaction may be too slow
1
Question Number
Acceptable Answer Additional Guidance Mark
7 (b) (iii) An explanation that makes reference to the following points:
(yellow to) green then blue (1)
when the blue colour initially forms, it mixes with the yellow
unreacted VO2+ (to turn green) (1)
Ignore colours caused by contamination with
reducing agent chosen
2
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Question
Number Acceptable Answer Additional Guidance Mark
7 (b) (iv) An explanation that makes reference to the following point:
justification of choice (1)
correct equation for reaction (1)
Eo value is between +0.34 V and −0.26 V
Allow by comparison of electrode potentials / calculation of Ecell / use of anti-clockwise rule
S2O3
2− + VO2+ + 2H+ → V3+ + H2O + ½S4O62−
or multiples
2
Question Number
Acceptable Answer Additional Guidance Mark
7 (c) (i) SO2 + ½O2 → SO3 Allow multiples
Ignore state symbols
1
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Question
Number Acceptable Answer Additional Guidance Mark
*7 (c)
(ii)
This question assesses a student’s ability to show a coherent and
logically structured answer with linkages and fully-sustained
reasoning.
Marks are awarded for indicative content and for how the answer is structured and shows lines of reasoning.
The following table shows how the marks should be awarded for
indicative content.
Number of indicative marking
points seen in answer
Number of marks awarded for indicative
marking points
6 4
5–4 3
3–2 2
1 1
0 0
The following table shows how the marks should be awarded for structure and lines of reasoning.
Number of marks
awarded for structure of answer and sustained
line of reasoning
Answer shows a coherent and logical structure with linkages and
fully sustained lines of reasoning demonstrated throughout
2
Answer is partially structured with
some linkages and lines of reasoning
1
Answer has no linkages between
points and is unstructured 0
Guidance on how the mark scheme should be
applied:
The mark for indicative content should be added to the mark for lines of reasoning. For example, an
answer with five indicative marking points which is partially structured with some linkages and lines of
reasoning scores 4 marks (3 marks for indicative content and 1 mark for partial structure and some
linkages and lines of reasoning). If there are no linkages between points, the same
five indicative marking points would yield an overall
score of 3 marks (3 marks for indicative content and no marks for linkages).
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Indicative Content:
V2O5 acts as a heterogeneous catalyst
SO2 is adsorbed onto surface and reacts with the V2O5
SO3 forms and is only weakly bonded to surface
the SO3 desorbs from the surface
oxygen reacts with the VO2, regenerating the V2O5
catalyst
reaction follows different mechanism with lower activation
energy
Ignore comments related to collision theory
6
(Total for Question 7 = 14 marks)
CHERRY HILL TUITION EDEXCEL CHEMISTRY A2 PAPER 32 MARK SCHEME
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Question
Number Acceptable Answer Additional Guidance Mark
8(a) reagent for step 1 (1)
product of step 1 (1)
reagent for step 2 (1)
KCN and HCN or KCN and H+ or HCN
Allow structural or displayed formulae
Allow name or formula of any mineral acid
3
Question
Number Acceptable Answer Additional Guidance Mark
8(b)
(1)
esterification (1)
2
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Question
Number Acceptable Answer Additional Guidance Mark
8(c)
NO2+ ion (1)
curly arrow from ring to electrophile (1)
formula of intermediate (1)
curly arrow from CH bond to ring and formation of H+ (1)
Ignore equation to produce electrophile
To any part of the electrophile including the plus sign
The horseshoe must cover at least three carbon atoms,
opening towards the carbon atom approached by the electrophile and at least part of the plus charge within the
horseshoe
4
(Total for Question 8 = 9 marks)
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Question
Number Acceptable Answer Additional Guidance Mark
9(a)
For Mg allow 0 or 8 electrons in outermost shell
Ignore inner shell electrons
2
Question Number
Acceptable Answer Additional Guidance Mark
9(b)(i)
amount of NaOH (1)
[NaOH] (1)
[NaF]eq (1)
Kc expression (1)
Value of Kc (1)
Example of calculation
11.7/1000 x 0.100 = 0.00117 / 1.17 x 10−3
0.00117/(25/1000) = 0.0468 mol dm−3
0.250 – 0.0468 = 0.2032 mol dm−3
Kc = [NaOH]2 / [NaF]2
0.0530 (no units)
5
Question Number
Acceptable Answer Additional Guidance Mark
9 (b) (ii) An answer that makes reference to the following point:
No, as temperature is likely to be different on different
days and this affects value of Kc
Allow ‘yes, but only if the temperature is the same’
1
(Total for Question 9 = 8 marks)
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Question Number
Acceptable Answer Additional Guidance Mark
10(a)(i) orange to colourless
Allow brown / yellow to colourless
1
Question Number
Acceptable Answer Additional Guidance Mark
10(a)(ii) A explanation that makes reference to the following points:
becomes polar / forms temporary dipole (1)
as electron density in C=C bond repels bond pair (of
electrons in bromine) (1)
Polar bromine can be shown by using a diagram
e.g.
2
Question
Number Acceptable Answer Additional Guidance Mark
10(a)(iii) addition (1)
structure (1)
Example of structure:
2
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Question Number
Acceptable Answer Additional Guidance Mark
10(a)(iv)
Ignore addition of square brackets and n
1
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Question
Number Acceptable Answer Additional Guidance Mark
10(b) Raw materials (1)
wood is renewable
and polystyrene uses slightly more petroleum fractions
Energy use (1)
paper cup uses nearly 4x as much energy
Water use (1) paper cup uses nearly 50x as much water
Air emissions (1) paper cup produces chlorine and more
sulfur dioxide both of which are toxic / acidic and
polystyrene cup produces a lot of hydrocarbons
Justification (2) Selection of either cup with two valid reasons
For example: polystyrene is more sustainable, as although it
uses up non-renewable raw materials, its
production requires much less energy which is likely to save on fossil fuel use
or paper is more sustainable, as no hydrocarbons are
emitted into the atmosphere and the raw materials are renewable and use less petroleum fractions
6
(Total for Question 10 = 12 marks)
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