A-level CHEMISTRY
7405/2 the latest version 2023 100% sure
Mark schemes are prepared by the Lead Assessment Writer and considered, together with the
... [Show More] relevantquestions,
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 inthis 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. Alternativeanswers 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.
It must be stressed that a mark scheme is a working document, in many cases further developed and expanded on
the basis of students’ reactions to a particular paper. Assumptions about future mark schemes on the basis of one
year’s document should be avoided; whilst the guiding principles of assessment remain constant, details will
change, depending on the content of a particular examinationpaper.
Further copies of this mark scheme are available from aqa.org.ukAS 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 aboutapplying 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 thediagram 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 secondmarking point etc.
2. Emboldening
2.1 In a list of acceptable answers where more than one mark is available ‘any two from’ isused,
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 themark.
2.3 Alternative answers acceptable for a mark are indicated by the use of OR. Different termsin the
mark scheme are shown by a / ; eg allow smooth / free movement.For example, in a question requiring 2 answers for 2 marks:
Correct
answers
Incorrect
answers (ie
incorrect rather
than neutral)
Mark (2) Comment
1 0 1
1 1 1
They have not exceeded the maximumnumber
of responses so there is no penalty.
1 2 0
They have exceeded the maximum numberof
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 two
3 1 1
The incorrect response cancels out one ofthe
two correct responses that gained credit.
3 2 0 Two incorrect responses cancel out the two
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 thiscase, 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 eac [Show Less]