AQA A-LEVEL CHEMISTRY PAPER 3 MARKING
SCHEME LATEST 2023 VERSION 1.0 FINAL
A−level
CHEMISTR7
7405/3
Paper 3
Mark scheme
June 2023
Version: 1.0 Final
,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.
3
, For example, in a question requiring 2 answers for 2 marks:
Incorrect
Correct answers (i.e.
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.
Examiners should also credit correct equations using multiples and fractions unless
otherwise stated in the ‘Comments’ column.
4
SCHEME LATEST 2023 VERSION 1.0 FINAL
A−level
CHEMISTR7
7405/3
Paper 3
Mark scheme
June 2023
Version: 1.0 Final
,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.
3
, For example, in a question requiring 2 answers for 2 marks:
Incorrect
Correct answers (i.e.
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.
Examiners should also credit correct equations using multiples and fractions unless
otherwise stated in the ‘Comments’ column.
4
