Pearson Edexcel International Advanced Level
Monday 12 January 2026
WCH11/01A
Paper
Afternoon (Time: 1 hour 30 minutes)
reference
Chemistry
Mark Scheme (Results)
International Advanced Subsidiary/Advanced Level
UNIT 1: Structure, Bonding and Introduction to
Organic Chemistry
Question Paper
You must have:
January 2026
Scientific calculator, ruler, HB pencil and Answer Book (sent separately)
Pearson Edexcel International Advanced Subsidiary Level
In Chemistry
Paper 01A: Structure, Bonding and Introduction to Organic
Chemistry
WCH11/01A
Turn over
P87623APearson Education Ltd.
C:1/1/1/1/1/1/1/
*P87623A*
, SECTION A
Edexcel and BTEC Qualifications
Answer ALL the questions in this section in the Answer Book.
You should aim to spend no more than 20 minutes on this section.
For each question, select one answer from A to D and put a cross in the box in the Edexcel and BTEC qualifications are awarded by Pearson, the UK’s
Answer Book. If you change your mind, put a line through the box and then mark your new largest awarding body. We provide a wide range of qualifications
answer with a cross . including academic, vocational, occupational and specific
1 What is the empirical formula of butane? programmes for employe a
qualifications websites at or .
Alternatively, you c
A C4H10
contact us page at
B C2H5
C CH2.5
D CnH2n + 2
Pearson: helping people progress, everywhere
(Total for Question 1 = 1 mark)
Pearson aspires to be the world’s leading learning company. Our aim is to help
2 When zinc is added to copper(II) sulfate solution, copper is formed. everyone progress in their lives through education. We believe in every kind of
(a) What is a possible name for this type of reaction? learning, for all kinds of people, wherever they are in the world. We’ve been
(1) involved in education for over 150 years, and by working across 70 countries, in
100 languages, we have built an international reputation for our commitment to
A addition
high standards and raising achievement through innovation in education. Find
B displacement out more about how we can help you and your students at:
C neutralisation
D substitution
(b) Which is the ionic half-equation for a process that takes place during
this reaction?
(1)
A Cu2+ + e– → Cu+
B Cu+ + e– → Cu
C Zn → Zn+ + e–
D Zn → Zn2+ + 2e–
January 2026
(Total for Question 2 = 2 marks) Question Paper Log Number P87623A
Publication Code WCH11_01A_2601_MS
All the material in this publication is
Pearson Education Ltd
2 P87623A
, General Marking Guidance
3 What is the name of the hydrocarbon shown using IUPAC rules?
H • All candidates must receive the same treatment. Examiners must mark the
first candidate in exactly the same way as they mark the last.
H C H H • Mark schemes should be applied positively. Candidates must be rewarded
H H C H H H C H H for what they have shown they can do rather than penalised for omissions.
H C C C C C H • Examiners should mark according to the mark scheme not according to their
H H H H C H H perception of where the grade boundaries may lie.
• There is no ceiling on achievement. All marks on the mark scheme should be
H
used appropriately.
A 2,2-dimethyl-4-ethylpentane • All the marks on the mark scheme are designed to be awarded. Examiners
B 2-ethyl-4,4-dimethylpentane should always award full marks if deserved, i.e. if the answer matches the
mark scheme. Examiners should also be prepared to award zero marks if the
C 3,5,5-trimethylhexane
candidate’s response is not worthy of credit according to the mark scheme.
D 2,2,4-trimethylhexane
• Where some judgement is required, mark schemes will provide the principles
(Total for Question 3 = 1 mark) by which marks will be awarded and exemplification may be limited.
• When examiners are in doubt regarding the application of the mark scheme
4 Which element is in the p-block and has atoms containing two unpaired electrons in
the ground state? to a candidate’s response, the team leader must be consulted.
• Crossed out work should be marked UNLESS the candidate has replaced it
A carbon
with an alternative response.
B fluorine
C lithium
D titanium
(Total for Question 4 = 1 mark)
5 Sea water contains 2.7 mg of sulfate ions per kilogram.
What is the concentration of sulfate ions in parts per million by mass?
A 2.7 × 10–6
B 2.7 × 10–3
C 2.7
D 2.7 × 103
(Total for Question 5 = 1 mark)
P87623A 3
Turn over
, Section A
6 How many ions are in 284 g of sodium sulfate, Na2SO4?
Question Answer Mark
Data: Avogadro constant = 6.0 × 10 mol 23 –1
number
Molar mass of sodium sulfate = 142 g mol–1 1 1
The only correct answer is B (C2H5)
A is incorrect because C4H10 is the molecular formula
A 1.2 × 1024
C is incorrect because the empirical formula is the whole number ratio of atoms present
B 2.4 × 1024
D is incorrect because the general formula for an alkane
24
C 3.6 × 10
D 8.4 × 1024 Question Answer Mark
number
(Total for Question 6 = 1 mark) 2a 1
The only correct answer is B (displacement)
3 3
7 100 cm of methane, CH4, is completely burned in 400 cm of oxygen. A is incorrect because it is not an addition reaction
3 C is incorrect because it is not a neutralisation reaction
What is the final volume of the gas mixture, in cm , when all volumes are measured at
room temperature and pressure? D is incorrect because it is not a substitution reaction
A 100
Question Answer Mark
B 200
number
C 300 2b 1
The only correct answer is D (Zn → Zn2+ + 2e ‒)
D 500 A is incorrect because Cu2+ has not gained an electron
(Total for Question 7 = 1 mark) B is incorrect because Cu+ was not a reactant
C is incorrect because Zn lost more than one electron
8 Which ion has the largest ionic radius?
A Ca2+
B Cl−
C K+
D S2−
(Total for Question 8 = 1 mark)
4 P87623A
Monday 12 January 2026
WCH11/01A
Paper
Afternoon (Time: 1 hour 30 minutes)
reference
Chemistry
Mark Scheme (Results)
International Advanced Subsidiary/Advanced Level
UNIT 1: Structure, Bonding and Introduction to
Organic Chemistry
Question Paper
You must have:
January 2026
Scientific calculator, ruler, HB pencil and Answer Book (sent separately)
Pearson Edexcel International Advanced Subsidiary Level
In Chemistry
Paper 01A: Structure, Bonding and Introduction to Organic
Chemistry
WCH11/01A
Turn over
P87623APearson Education Ltd.
C:1/1/1/1/1/1/1/
*P87623A*
, SECTION A
Edexcel and BTEC Qualifications
Answer ALL the questions in this section in the Answer Book.
You should aim to spend no more than 20 minutes on this section.
For each question, select one answer from A to D and put a cross in the box in the Edexcel and BTEC qualifications are awarded by Pearson, the UK’s
Answer Book. If you change your mind, put a line through the box and then mark your new largest awarding body. We provide a wide range of qualifications
answer with a cross . including academic, vocational, occupational and specific
1 What is the empirical formula of butane? programmes for employe a
qualifications websites at or .
Alternatively, you c
A C4H10
contact us page at
B C2H5
C CH2.5
D CnH2n + 2
Pearson: helping people progress, everywhere
(Total for Question 1 = 1 mark)
Pearson aspires to be the world’s leading learning company. Our aim is to help
2 When zinc is added to copper(II) sulfate solution, copper is formed. everyone progress in their lives through education. We believe in every kind of
(a) What is a possible name for this type of reaction? learning, for all kinds of people, wherever they are in the world. We’ve been
(1) involved in education for over 150 years, and by working across 70 countries, in
100 languages, we have built an international reputation for our commitment to
A addition
high standards and raising achievement through innovation in education. Find
B displacement out more about how we can help you and your students at:
C neutralisation
D substitution
(b) Which is the ionic half-equation for a process that takes place during
this reaction?
(1)
A Cu2+ + e– → Cu+
B Cu+ + e– → Cu
C Zn → Zn+ + e–
D Zn → Zn2+ + 2e–
January 2026
(Total for Question 2 = 2 marks) Question Paper Log Number P87623A
Publication Code WCH11_01A_2601_MS
All the material in this publication is
Pearson Education Ltd
2 P87623A
, General Marking Guidance
3 What is the name of the hydrocarbon shown using IUPAC rules?
H • All candidates must receive the same treatment. Examiners must mark the
first candidate in exactly the same way as they mark the last.
H C H H • Mark schemes should be applied positively. Candidates must be rewarded
H H C H H H C H H for what they have shown they can do rather than penalised for omissions.
H C C C C C H • Examiners should mark according to the mark scheme not according to their
H H H H C H H perception of where the grade boundaries may lie.
• There is no ceiling on achievement. All marks on the mark scheme should be
H
used appropriately.
A 2,2-dimethyl-4-ethylpentane • All the marks on the mark scheme are designed to be awarded. Examiners
B 2-ethyl-4,4-dimethylpentane should always award full marks if deserved, i.e. if the answer matches the
mark scheme. Examiners should also be prepared to award zero marks if the
C 3,5,5-trimethylhexane
candidate’s response is not worthy of credit according to the mark scheme.
D 2,2,4-trimethylhexane
• Where some judgement is required, mark schemes will provide the principles
(Total for Question 3 = 1 mark) by which marks will be awarded and exemplification may be limited.
• When examiners are in doubt regarding the application of the mark scheme
4 Which element is in the p-block and has atoms containing two unpaired electrons in
the ground state? to a candidate’s response, the team leader must be consulted.
• Crossed out work should be marked UNLESS the candidate has replaced it
A carbon
with an alternative response.
B fluorine
C lithium
D titanium
(Total for Question 4 = 1 mark)
5 Sea water contains 2.7 mg of sulfate ions per kilogram.
What is the concentration of sulfate ions in parts per million by mass?
A 2.7 × 10–6
B 2.7 × 10–3
C 2.7
D 2.7 × 103
(Total for Question 5 = 1 mark)
P87623A 3
Turn over
, Section A
6 How many ions are in 284 g of sodium sulfate, Na2SO4?
Question Answer Mark
Data: Avogadro constant = 6.0 × 10 mol 23 –1
number
Molar mass of sodium sulfate = 142 g mol–1 1 1
The only correct answer is B (C2H5)
A is incorrect because C4H10 is the molecular formula
A 1.2 × 1024
C is incorrect because the empirical formula is the whole number ratio of atoms present
B 2.4 × 1024
D is incorrect because the general formula for an alkane
24
C 3.6 × 10
D 8.4 × 1024 Question Answer Mark
number
(Total for Question 6 = 1 mark) 2a 1
The only correct answer is B (displacement)
3 3
7 100 cm of methane, CH4, is completely burned in 400 cm of oxygen. A is incorrect because it is not an addition reaction
3 C is incorrect because it is not a neutralisation reaction
What is the final volume of the gas mixture, in cm , when all volumes are measured at
room temperature and pressure? D is incorrect because it is not a substitution reaction
A 100
Question Answer Mark
B 200
number
C 300 2b 1
The only correct answer is D (Zn → Zn2+ + 2e ‒)
D 500 A is incorrect because Cu2+ has not gained an electron
(Total for Question 7 = 1 mark) B is incorrect because Cu+ was not a reactant
C is incorrect because Zn lost more than one electron
8 Which ion has the largest ionic radius?
A Ca2+
B Cl−
C K+
D S2−
(Total for Question 8 = 1 mark)
4 P87623A
