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Edexcel a level
chemistry question
paper 1 june 2024 +
mark scheme

Please check the examination details below before entering your candidate information
Candidate surname

Centre Number

Other names

Candidate Number

Pearson Edexcel Level 3 GCE

Monday 10 June 2024
Morning (Time: 1 hour 45 minutes)

Chemistry

Paper
reference

9CH0/01
 

Advanced

PAPER 1: Advanced Inorganic and Physical Chemistry

You must have:
Scientific calculator, Data Booklet, ruler

Total Marks

Instructions

Use black ink or ball-point pen
...

•
in the boxes at the top of this page with your name,
• Fill
centre number and candidate number
...

•
the questions in the spaces provided
• Answer
– there may be more space than you need
...

•
marks for each question are shown in brackets
• The
– use this as a guide as to how much time to spend on each question
...

A Periodic Table is printed on the back cover of this paper
...

•
Show all your working in calculations and include units where appropriate
...

Turn over

P76895A

©2024 Pearson Education Ltd
...



(a) Complete the table
...




(i) Complete the table to show the percentage abundance of 34S
...
02

33

S

34

S

0
...
02

(ii) Calculate the relative atomic mass (Ar ) of the sulfur in this sample using the
data in the table
...


(2)

(Total for Question 1 = 6 marks)
2

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Some questions must be answered with a cross in a box
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Answer ALL questions
...



(a) Explain the trend in the values of the first electron affinities of the
elements shown
...



...



...



...



...



...

The letters do not refer to the symbols of the elements
...



Three containers of soluble white solids have lost their labels but are known to be
calcium bromide, calcium iodide and potassium sulfate
...


(3)


...



...



...



...



...


(2)

calcium bromide

...


potassium sulfate

...


Solution

(2)
Formula of
precipitate with
silver nitrate

Colour of precipitate
with silver nitrate

Observation with
concentrated
aqueous ammonia

calcium bromide(aq)

calcium iodide(aq)

(c) Describe a chemical test for the sulfate ion giving the positive result
...



...



...
0450 mol dm−3?





The molar mass of K2SO4 is 174
...


(1)

A
1
...
84 g
C 19
...
4 g
(Total for Question 3 = 10 marks)

6

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(b) Separate aqueous solutions of calcium bromide and of calcium iodide reacted
with acidified silver nitrate to produce a precipitate
...


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4 This question is about acids, bases and buffers
...


(1)


...




(b) Which could be the titration curve when 0
...
0 cm3 of 0
...

(4)

Name of acid

Formula of acid

pH of a solution of
0
...
00

sulfuric acid

H2SO4

0
...
94


...



...



...



...



...



...



...



...



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8

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Comment on these pH values
...


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(d) One of the systems controlling the pH of blood is the
carbonic acid–hydrogencarbonate buffer system
...

State symbols are not required
...


Calculate the pH of the blood sample
...

Ka for carbonic acid = 4
...
0240 mol dm−3



[H2CO3] = 0
...


Equilibrium 2


H2CO3(aq)  H+(aq) + HCO3−(aq)

(i) When a person exercises vigorously the concentration of carbon dioxide (aq)
in the blood increases
...

Refer to the equilibria in your answer
...


(2)


...



...



...



...




(ii) Explain how the carbonic acid–hydrogencarbonate buffer system in
Equilibrium 2 acts to restore the pH of the blood after a person has exercised
...



...



...



...


(Total for Question 4 = 14 marks)

10

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Equilibrium 1 CO2(aq) + H2O(l)  H2CO3(aq)

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5 This question is about ‘Direct Ethanol Fuel Cells’ which are being developed to power
small electronic devices
...

C2H5OH(l) + 3O2(g) → 3H2O(l) + 2CO2(g)



(a) Calculate the enthalpy change for the reaction using the
mean bond enthalpy data
...
 kJ mol−1



*P76895A01128*

11

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(b) (i) Complete the enthalpy cycle for the overall reaction in the Direct Ethanol
Fuel Cell
...


Δf H   / kJ mol−1

C2H5OH(l)

−277

CO2(g)

−394

H2O(l)

−286

C2H5OH(l) + 3O2(g)



Δr H

3H2O(l) + 2CO2(g)

(ii) Calculate a value for the enthalpy change of the Direct Ethanol Fuel Cell
reaction, using your cycle
...
 kJ mol−1

12

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Substance

(2)

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(c) Give two reasons for the difference between your calculated values in (a) and (b)
...



...



...



...


At the other electrode, the hydrogen ions and electrons combine with oxygen to
form water
...

State symbols are not required
...



...



...



...



...



...



...



...



...



...



...



...



...

Include any relevant electronic configurations
...



...



...



...



...



...



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...



...



...


(Total for Question 6 = 6 marks)



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15

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The contact process is used in the manufacture of sulfuric acid
...




The equation for the second stage is shown
...


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(b) Write two equations that show the conversion of SO2 and O2 into SO3 by using
V2O5 as the catalyst
...






(c) Which row of the table shows the correct colour of the solution and oxidation
number of vanadium in the aqueous ions shown?
Aqueous ion

Colour of solution

Oxidation number
of vanadium

A

VO+2

yellow

+3

B

VO2+

green

+4

C

VO2+

yellow

+5

D

VO2+

blue

+5

(2)

(1)

(d) What is the value of the cell potential for the reaction of Zn and VO+2  ?
Use your Data Booklet
...
76 V
B
+0
...
24 V
D
−1
...



(a) Draw dot-and-cross diagrams of the ions in magnesium hydroxide, showing the
outer shell electrons only
...




(b) Which definition correctly describes the enthalpy change of solution, ΔsolH ?

(2)

(1)

Enthalpy change of solution, ΔsolH
The enthalpy change when 1 mol of gaseous ions dissolves in
A
sufficient water to give an infinitely dilute solution
...


C

The enthalpy change when 1 mol of gaseous ions dissolves in
sufficient water to give a solution of concentration 1 mol dm−3 
...


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*P76895A01928*

19

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(c) The table shows the information needed to calculate the
standard enthalpy change of formation of magnesium fluoride
...

The cycle is not drawn to scale
...


*P76895A02128*

MgF2(s)

(1)

21

Turn over

(4)

Compound

Experimental lattice energy 
/ kJ mol−1

Theoretical lattice energy 
/ kJ mol−1

MgF2

−2957

−2913

MgI2

−2327

−1944


...



...



...



...



...


(Total for Question 8 = 12 marks)

22

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Explain the differences in these values
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9 Sodium hydrogencarbonate is used as a raising agent in baking as carbon dioxide gas
is released when it undergoes thermal decomposition
...

2NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(l)    ΔrH = +91
...
7

135
...
6

69
...




(b) Calculate the minimum temperature, in degrees Celsius (°C), at which an oven
should be set for this reaction to be thermodynamically feasible
...
 °C
(Total for Question 9 = 5 marks)



*P76895A02328*

23

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10 Vitamin C has the molecular formula C6H8O6 
...
50 g tablet contained 6%
of vitamin C by mass
...

The procedure involved a series of steps
...


A 2
...
0 cm3 
...


(3)


...



...



...



...



...

IO3− +




...


H+ → 3I2 +

(1)


...
50 × 10−4 moles of iodine were produced in
the flask
...




10
...

C6H8O6(aq) + I2(aq) → C6H6O6(aq) + 2HI(aq)
The unreacted iodine in the conical flask was titrated with a solution of
0
...

The mean titre was 14
...

2S2O32–(aq) + I2(aq) → 2I–(aq) + S4O62−(aq)


(i) State the indicator used in this titration, giving the colour change that would
be observed at the end-point
...



...



...
0 cm3 of 0
...


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(b) Step 2    Producing a known amount of iodine
...


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(6)

(Total for Question 10 = 14 marks)
TOTAL FOR PAPER = 90 MARKS

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*P76895A02828*

28

Mark Scheme (Results)
Summer 2024
Pearson Edexcel GCE
In Chemistry (9CH0)
Paper 01: Advanced Inorganic and
Physical Chemistry

Edexcel and BTEC Qualifications
Edexcel and BTEC qualifications are awarded by Pearson, the UK’s largest awarding body
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We’ve been involved in education for over 150 years, and by working across
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pearson
...
Examiners
must mark the first candidate in exactly the same way as they
mark the last
...
Candidates must
be rewarded for what they have shown they can do rather than
penalised for omissions
...


•

There is no ceiling on achievement
...


•

All the marks on the mark scheme are designed to be awarded
...
e
...
Examiners should also
be prepared to award zero marks if the candidate’s response
is not worthy of credit according to the mark scheme
...


•

When examiners are in doubt regarding the application of the
mark scheme to a candidate’s response, the team leader must
be consulted
...


Using the Mark Scheme
Examiners should look for qualities to reward rather than faults to penalise
...
Examiners should therefore read carefully and consider every response:
even if it is not what is expected it may be worthy of credit
...

/ means that the responses are alternatives and either answer should receive full
credit
...

Phrases/words in bold indicate that the meaning of the phrase or the actual word is
essential to the answer
...

Candidates must make their meaning clear to the examiner to gain the mark
...
Do not give credit for correct words/phrases which
are put together in a meaningless manner
...

Quality of Written Communication
Questions which involve the writing of continuous prose will expect candidates to:
• write legibly, with accurate use of spelling, grammar and punctuation in order to
make the meaning clear
• select and use a form and style of writing appropriate to purpose and to complex
subject matter
• organise information clearly and coherently, using specialist vocabulary when
appropriate
...

Questions where QWC is likely to be particularly important are indicated (QWC) in the
mark scheme, but this does not preclude others
...
02 – 0
...
02 =) 4
...
02 × 32) + (0
...
21 × 34) + (36 × 0
...
0925)
Allow TE on 1(b)(i)
...
09
Allow units of g mol−1 / g mol−
Allow units of g/mol
Do not award any other unit
Correct answer with no working scores 2
(Total for Question 1 = 6 marks)

Question
Number
2(a)

Acceptable Answer
An explanation that makes reference to the following points:

•

electron affinity becomes less negative / less exothermic /
less energy is released going from chlorine to iodine / down
the group

•

atomic radius increases / number of shells increases /
increased distance between the nucleus and
the outer / valence electron(s)
and
there is less attraction between the nucleus and the
incoming / added electron / valence electron(s)

•

(there is) increased shielding (from inner electron shells)

•

(increased) shielding outweighs the effect of increasing
nuclear charge
or
(increased) repulsion between the (inner) electron shells and
the incoming electron outweighs the effect of increasing
nuclear charge
or
(increased) distance of the outer shell / energy level
outweighs the effect of increasing nuclear charge

Additional Guidance
Allow reverse arguments up the group /
comparison of specific elements
...

(1) Allow the electron affinity becomes more
positive / more endothermic going from
chlorine to iodine
Ignore electron affinity increases /
decreases
Do not award requires / produces energy
(1) Do not award any reference to ions, ionic
radius, charge or charge density for M2
unless point is clearly made that ions are
being formed from atoms
(1) Allow there is an increase in repulsion
between the (inner) electron shells and the
incoming electron(s)
(1)

Mark
(4)

Question
Number
2(b)

Answer
The only correct answer is D (Ca2+)

Mark
(1)

A is not correct because S2– has fewer protons than Ca2+ and has the largest ionic radius of those listed
B is not correct because Cl− has fewer protons than Ca2+ and has the second largest ionic radius
C is not correct because K+ has fewer protons than Ca2+ and has the second smallest ionic radius

Question
Number
2(c)(i)

Answer
The only correct answer is D (1086, 2353, 4621, 6223, 37832)
A is not correct because these are the successive ionisation energies of a Group 3 element
B is not correct because these are the successive ionisation energies of a transition element
C is not correct because these are the successive ionisation energies of a Group 2 element

Mark
(1)

Question
Number
2(c)(ii)

Answer
The only correct answer is C (738, 1451, 7733, 10541, 13629)

Mark
(1)

A is not correct because these are the successive ionisation energies of a p-block element
B is not correct because these are the successive ionisation energies of a d-block element
D is not correct because these are the successive ionisation energies of a p-block element
(Total for Question 2 = 7 marks)

Question
Number
3(a)(i)

Acceptable Answer

Additional Guidance

An explanation that makes reference to the following points:

(3)

•

platinum / nichrome wire

(1) Allow NiCr for nichrome
Allow silica rod
Allow loop for wire
Ignore inoculating / sterilising
Do not award just nickel or chromium
Do not award splint

•

dip (the wire) into (concentrated) hydrochloric acid /
HCl(aq) / HCl

(1) Allow mention of HCl((aq)) before or after
dipping wire into solid eg cleaning or mixing
solid and HCl((aq)) to make a paste
Ignore just acid
Do not award other acids
Allow salt / compound / paste / solid for
sample
Do not award element / metal for sample

•

dip the wire / silica rod into the sample
and
place in a (blue / roaring / non-luminous) flame

Mark

(1) Allow on / over / above / under the flame for
‘in’
Do not award reference to safety / yellow
flame
Do not award burn in the flame

Question
Number
3(a)(ii)

Acceptable Answer

Additional Guidance

A description that makes reference to the following points:
calcium bromide and calcium iodide: orange–red / brick−red

•

potassium sulfate: lilac

calcium bromide correct
calcium iodide correct

(1) Allow orange / red / yellow-red /
yellow- orange
Do not award brown, crimson, dark-red,
carmine or ruby
(1) Do not award purple / mauve / violet /
pink / blue-lilac

Additional Guidance

Mark
(2)

Solution

•

(2)

•

Question
Acceptable Answer
Number
3(b)
A description that makes reference to the
following points:

•

Mark

(1)

calcium
bromide(aq)

Formula of
precipitate
with silver
nitrate
AgBr

(1)
calcium
iodide(aq)

AgI

Colour of
precipitate
with silver
nitrate
cream /
paleyellow /
off white

Observation with
concentrated
aqueous ammonia
dissolves /
disappears /
Allow soluble
does not dissolve /
remains / no change

yellow
Allow insoluble /
no reaction

If no other mark is awarded then award 1 mark for 4 correct boxes
Ignore state symbols

Question
Acceptable Answer
Number
3(c)
A description that makes reference to the following points:

Question
Number
3(d)

Additional Guidance

Mark
(2)

•

add (dilute) HCl / (dilute) HNO3 and (a solution of) barium
chloride / BaCl2 / barium nitrate / Ba(NO3)2
(to a sulfate solution)

(1) Allow concentrated HCl
Do not award just ‘acidified’
Do not award incorrect formulae

•

white precipitate / solid

(1) Do not award powder
M2 depends on M1 or near miss
(i
...
96 g)

(1)

B is not correct because it is the mass for 1 dm3 of a solution of concentration 0
...
45 mol dm−3
D is not correct because this would be the mass for 4
...
100 mol dm−3 of a strong acid and 0
...
100 mol dm-3 of a weak acid and 0
...
100 mol dm-3 of a strong acid and 0
...


Question
Number
4(d)(ii)

Acceptable Answer

Additional Guidance
Example of calculation

•

rearrangement or substitution of values into
the equation

(1) [H+] = Ka × [H2CO3 ]
[HCO3−]

•

calculation of [H+]

(1) [H+] = (4
...
0020)
0
...
75 × 10−8 (mol dm−3)
Allow TE from an incorrect expression in 4(c)(i) for 1 mark

•

calculation of pH

(1) pH = −log10 [H+]
= − log10 (3
...
426 / 7
...
4
Standalone mark
Allow TE on incorrect value
Ignore SF except 1 SF

Mark
(3)

Question
Number
4(e)(i)

Acceptable Answer

Additional Guidance

An answer that makes reference to the following points:

(2)

•

the position of the first and second equilibria are shifted
to the right (to use up the CO2)

(1) Allow reference to each specific equilibrium
and a comment about more of the relevant
products being produced if no mention of a shift
to the right
...

Do not award the H+ ions neutralise the HCO3−
Ignore any mention of OH− ions shifting
equilibrium 2 to the left
...

Allow TE for M3
Allow SF apart from 1SF
...
g just fH /
correct numbers left hand −277 and right hand −1646
or 3 × −286 and 2 × −394
Allow omission of state symbols on the arrows
...

Correct answer scores 1
No TE on incorrect cycle

Mark
(1)

Question
Acceptable Answer
Number
5(c)
An answer that makes reference to the following point:

Question
Number
5(d)

Additional Guidance

(2)

•

(values are different because) mean bond
enthalpies have been used (in the first calculation)
(which are different from the actual values)

•

(values are different) because the bond enthalpy values (1)
are given for substances in the gas state (and water and
ethanol are liquids)

(1)

Acceptable Answer

Ignore references to standard conditions

Additional Guidance

An answer that makes reference to the following
points:
•

oxidation half−equation

•

reduction half−equation

Mark

Mark
(2)

(1)

C2H5OH + 3H2O → 2CO2 + 12e(−) + 12H+

(1)

4H+ + 4e(−) + O2 → 2H2O
Allow multiples
Allow reversible arrows but equations must be
written forwards
Comment: Allow 1 mark if both equations correct
but oxidation and reduction swapped
Ignore state symbols even if incorrect
(Total for Question 5 = 10 marks)

Question
Number
*6

Acceptable Answer

Additional Guidance

This question assesses a student’s ability to show a
coherent and logically structured answer with linkages and fullysustained reasoning
...

The following table shows how the marks should be
awarded for indicative content
...

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
...

Answer has no linkages between points
and is unstructured
...

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)
...

In general it would be expected
that 5 or 6 indicative points would get 2 reasoning
marks, and 3 or 4 indicative points would get 1 mark
for reasoning, and 0, 1 or 2
indicative points would score zero marks for
reasoning
...
If no reasoning mark(s) awarded
do not deduct mark(s)
...


•

IP3 (energy gap)
energy gap / H /  (between d-orbitals) is different in
different (metal) ions / between Cu2+ and Fe2+ ions

Allow energy levels for energy gap as long as it
is clear they mean in the d-subshell / between the
split d-orbitals

•

IP4 (electron promoted)
electron is promoted / excited / d−d transition
and
absorbing (visible) light energy / photons of different
wavelength / colour

Allow transition / promotion between energy
levels
Do not award transition / promotion between
d-subshells

•

IP5 (colour)
complementary colour seen / transmitted / reflected

•

IP6 (zinc)
(zinc ions / Zn2+) colourless because the
(3)-d subshell / d-orbitals in Zn2+ are
full /
and
Zn2+ is [Ar] 3d10 / 1s2, 2s2, 2p6, 3s2, 3p6, 3d10
(and so d-d transitions cannot occur)

Allow colour / light not absorbed seen
Do not award reference to electrons returning to
the ground state or emission of colour / light
Ignore zinc (3)d subshell does not split
Ignore zinc cannot bind ligands
Allow no space for an electron to be promoted
Do not award shell for subshell
Penalise the incorrect mention of a single
d-orbital instead of d-orbitals or d-subshell once
only in whole response

(Total for Question 6 = 6 marks)
Question
Number
7(a)(i)

Answer
The only correct answer is D (

, atm−½)

p(SO3)

Mark
(1)

½

p(SO2) p(O2)

A is not correct because the expression is correct but the units are incorrect
B is not correct because both the expression and the units are incorrect
C is not correct because the expression is not correct
Question
Number
7(a)(ii)

Answer
The only correct answer is B (temperature)
A is not correct because this would affect the rate of the reaction but not the value of Kp
C is not correct because this would affect the rate of the reaction but not the value of Kp
D is not correct because this would affect the rate of the forward reaction temporarily but not the value of Kp

Mark
(1)

Question
Number
7(b)

Acceptable Answer

Additional Guidance

An answer that makes reference to the following points:
•

SO2 + V2O5 → SO3 + V2O4

•

V2O4 + ½ O2 → V2O5

Mark
(2)

(1)
(1) Allow multiples
Allow reversible arrows
Ignore state symbols even if incorrect
Do not award equations with electrons
Allow for 2 marks any balanced equations
showing formation of a lower oxidation state
oxide by reaction with SO2 and a higher
oxidation state by reaction with O2
Example
2SO2 + V2O5 → 2SO3 + V2O3
V2O3 + O2 → V2O5
Allow use of 2VO2 instead of V2O4 in both
equations

Question
Number
7(c)

Answer
The only correct answer is C (VO2+

yellow

Mark

+5 )

(1)

A is not correct as although the colour is correct for VO2+ the oxidation number is incorrect
B is not correct as although the oxidation number of vanadium is correct, VO2+ is blue
D is not correct as VO2+ as although the colour of the solution is blue, the oxidation number of vanadium in VO2+
is +4
Question
Number
7(d)

Answer
The only correct answer is A (+1
...
)
A is not correct as the mention of gaseous ions is incorrect
C is not correct as the mention of gaseous ions is incorrect and the concentration is incorrect
D is not correct as the concentration is incorrect

Mark

Mark
(1)

Question
Number
8(c)(i)

Answer and Additional Guidance

Mark
(4)

•

correct letters B, D, E, F, G or correct values corresponding to their cycle, G and B must be on the
correct boxes

(1)

•

multiplying F and G by 2 (must be seen on the cycle for this mark)

(1)

•

correct formulae in every box

(1)

•

state symbols and electrons (charge does not need to be shown on electrons)

(1)

Accept order of alternative order of boxes 2 – 3 – 1 with accompanying letters etc

Question
Number
8(c)(ii)

Acceptable Answer

Additional Guidance
Example of calculation

•

correct answer

(148 + (2 × 79) + 738 + 1451 + (−328 × 2) + (−2957))
= −1118 (kJ mol−1 )
Comment if −1118 seen then award the mark no matter what
their cycle indicates
No TE on incorrect values mis-transcribed on their cycle
Allow TE if matches cycle
−790 scores 1 (electron affinity not doubled)
−869 scores 1 (both values not doubled)
−1197 scores 1 (atomisation not doubled)

Mark
(1)

Question
Number
8(c)(iii)

Acceptable Answer
An explanation that makes reference to the following points:
•

(theoretical and experimental values of MgF2 are close / similar as)
MgF2 is (nearly) 100% ionic

(1)

•

(theoretical and experimental values of MgI2 are different as) MgI2
has some covalent character / more covalent character than MgF2

(1)

•

I− / iodide ions are more polarisable (than F− (ions)) / highly
polarisable / because the I− ions are larger / have a larger radius

(1)

•

values for MgF2 are more negative / more exothermic than for MgI2
as the (ionic) bonding is stronger in MgF2 (because the F− ion is
smaller than the I− ion)

Additional Guidance

Mark

Allow reverse argument throughout

(4)

Allow MgF2 is more ionic than
MgI2

(1)

Allow iodine ions / fluorine ions
Allow I− can be distorted more
Allow bond between Mg and I more
polarised as long as ions mentioned
in response
...
g
...
6 + 69
...
7)
= (+) 215
...
2151 (kJ K−1 mol−1)
(G = H – T Ssystem)
= (+ 91
...
1)
= (+) 27500 J mol−1 / 27500
...
500 kJ mol−1 / 27
...
6 / 0
...
8 K
425
...
8/ 153 (oC)
Allow 160 (oC)
Do not award 150 (oC) if rounded down
Do not award a negative answer for the
temperature
...
1 + (−91600 / T)
T = −91600 / −215
...
8
(1)
Conversion to oC = 425
...
8 oC
(1)
TE from answer to 9(a)
Ignore SF except 1SF
(Total for Question 9 = 5 marks)

Question
Number
10(a)

Acceptable Answer

Additional Guidance

An answer that makes reference to the following points:
•

(dissolve ) in deionised water (in a beaker)
and
transfer to a volumetric flask

Steps have to be in a logical order
...
01 × 0
...
5 × 10−4

•

moles iodine generated

(1)

3 × 2
...
5 × 10−4

Mark
(2)

Allow calculation shown in one step
...
40 × 0
...
44 × 10−3 / 0
...
44 × 10−3 = 7
...
00072
2

•

moles of iodine that reacted with 10
...
0 cm3
vitamin C tablet solution

(1)

= 7
...
2 × 10−4
= 3
...
00003

•

moles of ascorbic acid in 250 cm3 solution (1 tablet)

(1)

= 3
...
5 × 10−4 / 0
...
5 × 10−4 × 176 = 0
...
5 = 0
...
132 g)

Percentage = 0
...
50 × 100 = 5
...
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