AS-Level EDEXCEL 2025 Chemistry PAPER 2 Mark Scheme
Mark Scheme (Results)
Summer 2025
Pearson Edexcel Level GCE Advance Subsidiary In Chemistry (8CH0)
Paper 02: Core Organic and Physical Chemistry
Using the Mark Scheme
Examiners should look for qualities to reward rather than faults to penalise. This does NOT mean giving credit for incorrect or inadequate
answers, but it does mean allowing candidates to be rewarded for answers showing correct application of principles and knowledge.
Examiners should therefore read carefully and consider every response: even if it is not what is expected it may be worthy of credit.
The mark scheme gives examiners:
an idea of the types of response expected
how individual marks are to be awarded
the total mark for each question
, examples of responses that should NOT receive credit.
/ means that the responses are alternatives and either answer should receive full credit.
( ) means that a phrase/word is not essential for the award of the mark, but helps the examiner to get the sense of the expected answer.
Phrases/words in bold indicate that the meaning of the phrase or the actual word is essential to the answer.
ecf/TE/cq (error carried forward) means that a wrong answer given in an earlier part of a question is used correctly in answer to a later part
of the same question.
Candidates must make their meaning clear to the examiner to gain the mark. Make sure that the answer makes sense. Do not give credit
for correct words/phrases which are put together in a meaningless manner. Answers must be in the correct context.
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. Full
marks will be awarded if the candidate has demonstrated the above abilities.
Questions where QWC is likely to be particularly important are indicated (QWC) in the mark scheme, but this does not preclude others.
, Question
Answer Mark
Number
1(a) The only correct answer is D (C10H16) (1)
A is incorrect because this answer miscounts both the number of carbon atoms in the skeletal formula and the number
of hydrogen atoms in the skeletal formula, and it is the empirical formula
B is incorrect because C5H8 is the empirical formula of myrcene
C is incorrect because this answer miscounts the number of hydrogen atoms in the skeletal formula
Question
Answer Mark
Number
1(b) The only correct answer is B (3) (1)
A is incorrect because there are three C=C double bonds where bromine could add
C is incorrect because there are three C=C double bonds where bromine could add
D is incorrect because this is the number of bromine atoms added and not the number of bromine molecules
Mark Scheme (Results)
Summer 2025
Pearson Edexcel Level GCE Advance Subsidiary In Chemistry (8CH0)
Paper 02: Core Organic and Physical Chemistry
Using the Mark Scheme
Examiners should look for qualities to reward rather than faults to penalise. This does NOT mean giving credit for incorrect or inadequate
answers, but it does mean allowing candidates to be rewarded for answers showing correct application of principles and knowledge.
Examiners should therefore read carefully and consider every response: even if it is not what is expected it may be worthy of credit.
The mark scheme gives examiners:
an idea of the types of response expected
how individual marks are to be awarded
the total mark for each question
, examples of responses that should NOT receive credit.
/ means that the responses are alternatives and either answer should receive full credit.
( ) means that a phrase/word is not essential for the award of the mark, but helps the examiner to get the sense of the expected answer.
Phrases/words in bold indicate that the meaning of the phrase or the actual word is essential to the answer.
ecf/TE/cq (error carried forward) means that a wrong answer given in an earlier part of a question is used correctly in answer to a later part
of the same question.
Candidates must make their meaning clear to the examiner to gain the mark. Make sure that the answer makes sense. Do not give credit
for correct words/phrases which are put together in a meaningless manner. Answers must be in the correct context.
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. Full
marks will be awarded if the candidate has demonstrated the above abilities.
Questions where QWC is likely to be particularly important are indicated (QWC) in the mark scheme, but this does not preclude others.
, Question
Answer Mark
Number
1(a) The only correct answer is D (C10H16) (1)
A is incorrect because this answer miscounts both the number of carbon atoms in the skeletal formula and the number
of hydrogen atoms in the skeletal formula, and it is the empirical formula
B is incorrect because C5H8 is the empirical formula of myrcene
C is incorrect because this answer miscounts the number of hydrogen atoms in the skeletal formula
Question
Answer Mark
Number
1(b) The only correct answer is B (3) (1)
A is incorrect because there are three C=C double bonds where bromine could add
C is incorrect because there are three C=C double bonds where bromine could add
D is incorrect because this is the number of bromine atoms added and not the number of bromine molecules
