This document contains the AQA A-Level Chemistry Paper 1 Mark Scheme from the 2024 exam series, get yours now to prepare for mocks and revision.
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A-level
CHEMISTRY
7405/1
Paper 1 Inorganic and Physical Chemistry
Mark scheme
June 2024
Version: 1.0 Final
, MARK SCHEME – A-LEVEL CHEMISTRY – 7405/1 – JUNE 2024
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 the mark
scheme) are not penalised.
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, MARK SCHEME – A-LEVEL CHEMISTRY – 7405/1 – JUNE 2024
For example, in a question requiring 2 answers for 2 marks:
Incorrect
Correct answers (ie
Mark (2) Comment
answers incorrect rather
than neutral)
1 0 1
They have not exceeded the maximum
1 1 1 number of responses so there is no
penalty.
They have exceeded the maximum number
1 2 0 of responses so the extra incorrect
response cancels the correct one.
2 0 2
2 1 1
2 2 0
3 0 2 The maximum mark is 2
The incorrect response cancels out one of
3 1 1 the two correct responses that gained
credit.
Two incorrect responses cancel out the two
3 2 0
marks gained.
3 3 0
3.2 Marking procedure for calculations
Full marks should be awarded for a correct numerical answer, without any working
shown, unless the question states ‘Show your working’ or ‘justify your answer’. In this
case, the mark scheme will clearly indicate what is required to gain full credit.
If an answer to a calculation is incorrect and working is shown, process mark(s) can
usually be gained by correct substitution / working and this is shown in the ‘Comments’
column or by each stage of a longer calculation.
3.3 Errors carried forward, consequential marking and arithmetic errors
Allowances for errors carried forward are most likely to be restricted to calculation
questions and should be shown by the abbreviation ECF or consequential in the marking
scheme.
An arithmetic error should be penalised for one mark only unless otherwise amplified in
the marking scheme. Arithmetic errors may arise from a slip in a calculation or from an
incorrect transfer of a numerical value from data given in a question.
3.4 Equations
In questions requiring students to write equations, state symbols are generally ignored
unless otherwise stated in the ‘Comments’ column.
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, MARK SCHEME – A-LEVEL CHEMISTRY – 7405/1 – JUNE 2024
Examiners should also credit correct equations using multiples and fractions unless
otherwise stated in the ‘Comments’ column.
3.5 Oxidation states
In general, the sign for an oxidation state will be assumed to be positive unless
specifically shown to be negative.
3.6 Interpretation of ‘it’
Answers using the word ‘it’ should be given credit only if it is clear that the ‘it’ refers to the
correct subject.
3.7 Phonetic spelling
The phonetic spelling of correct scientific terminology should be credited unless there is a
possible confusion with another technical term or if the question requires correct IUPAC
nomenclature.
3.8 Brackets
(…..) are used to indicate information which is not essential for the mark to be awarded
but is included to help the examiner identify the sense of the answer required.
3.9 Ignore / Insufficient / Do not allow
Ignore or insufficient is used when the information given is irrelevant to the question or not
enough to gain the marking point. Any further correct amplification could gain the marking
point.
Do not allow means that this is a wrong answer which, even if the correct answer is
given, will still mean that the mark is not awarded.
3.10 Marking crossed out work
Crossed out work that has not been replaced should be marked as if it were not crossed
out, if possible. Where crossed out work has been replaced, the replacement work and
not the crossed out work should be marked.
3.11 Reagents
The command word ‘Identify’, allows the student to choose to use either the name or the
formula of a reagent in their answer. In some circumstances, the list principle may apply
when both the name and the formula are used. Specific details will be given in mark
schemes.
The guiding principle is that a reagent is a chemical which can be taken out of a bottle or
container. Failure to identify complete reagents will be penalised, but follow-on marks
(eg for a subsequent equation or observation) can be scored from an incorrect attempt
(possibly an incomplete reagent) at the correct reagent. Specific details will be given in
mark schemes.
For example, no credit would be given for:
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