A-level
CHEMISTRY
7405/3
Paper 3
Mark scheme
June 2023
Version: 1.0 Final
*236A7405/3/MS*
Page 1
, MARK SCHEME – A-LEVEL CHEMISTRY – 7405/3 – JUNE
2023
Mark schemes are prepared by the Lead Assessment Writer and considered, together with
the relevant questions, by a panel of subject teachers. This mark scheme includes any
amendments made at the standardisation events which all associates participate in and is
the scheme which was used by them in this examination. The standardisation process
ensures that the mark scheme covers the students’ responses to questions and that every
associate understands and applies it in the same correct way.
As preparation for standardisation each associate analyses a number of students’ scripts.
Alternative answers not already covered by the mark scheme are discussed and legislated
for. If, after the standardisation process, associates encounter unusual answers which have
not been raised they are required to refer these to the Lead Examiner.
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, MARK SCHEME – A-LEVEL CHEMISTRY – 7405/3 – JUNE
2023
AS and A-Level Chemistry
Mark Scheme Instructions for Examiners
1. General
The mark scheme for each question shows:
the marks available for each part of the question
the total marks available for the question
the typical answer or answers which are expected
extra information to help the examiner make his or her judgement and help to
delineate what is acceptable or not worthy of credit or, in discursive answers, to
give an overview of the area in which a mark or marks may be awarded.
The extra information in the ‘Comments’ column is aligned to the appropriate
answer in the left- hand part of the mark scheme and should only be applied to
that item in the mark scheme.
You should mark according to the contents of the mark scheme. If you are in any
doubt about applying the mark scheme to a particular response, consult your Team
Leader.
At the beginning of a part of a question a reminder may be given, for example:
where consequential marking needs to be considered in a calculation; or the answer
may be on the diagram or at a different place on the script.
In general the right-hand side of the mark scheme is there to provide those extra
details which might confuse the main part of the mark scheme yet may be helpful
in ensuring that marking is straightforward and consistent.
The use of M1, M2, M3 etc in the right-hand column refers to the marking points in
the order in which they appear in the mark scheme. So, M1 refers to the first
marking point, M2 the second marking point etc.
2. Emboldening
2.1 In a list of acceptable answers where more than one mark is available ‘any
two from’ is used, with the number of marks emboldened. Each of the
following bullet points is a potential mark.
2.2 A bold and is used to indicate that both parts of the answer are required to
award the mark.
2.3 Alternative answers acceptable for a mark are indicated by the use of OR.
Different terms in the mark scheme are shown by a / ; eg allow smooth / free
movement.
3. Marking points
3.1 Marking of lists
This applies to questions requiring a set number of responses, but for which
students have provided extra responses. The general ‘List’ principle to be
followed in such a situation is that ‘right + wrong = wrong’.
Each error / contradiction negates each correct response. So, if the number
of error / contradictions equals or exceeds the number of marks available for
the question, no marks can be awarded.
However, responses considered to be neutral (often prefaced by ‘Ignore’ in
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, MARK SCHEME – A-LEVEL CHEMISTRY – 7405/3 – JUNE
2023
the mark scheme) are not penalised.
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