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AQA A-Level CHEMISTRY 7405/2 Paper 2 Organic and Physical Chemistry Mark scheme June 2022

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AQA A-Level CHEMISTRY 7405/2 Paper 2 Organic and Physical Chemistry Mark scheme June 2022. Brown colour removed Goes colourless Allow (orange) brown to colourless Allow purple to colourless 1 (AO3) Question Answers Additional Comments/Guidelines Mark 01.5 As T increases rate (1/t ) increases OR time for completion decreases Exponentially OR By a greater/ increasing factor Many more particles have E ≥ Ea Or rate increases more and more as temp increases i.e. description of exponential increase NOT just higher collision frequency NOT just more successful collisions M1 M2 M3 (2 x AO1, 1 x AO2) Question Answers Additional Comments/Guidelines Mark 01.6 Time = 1 /0.03 = 33 s 1 (AO2) MARK SCHEME – A-LEVEL CHEMISTRY – 7405/2 – JUNE 2022 13 Question Answers Additional Comments/Guidelines Mark 01.7 ln (1.55 x 10–5 / 1.70 x 10–4 ) = Ea /R ( 1 /333 – 1 /303) –2.39 = Ea /R (–2.97 × 10–4 ) 2.39 × 8.31/2.97 × 10–4 = Ea 66937 66.9 kJ mol–1 Insertion of correct values Evaluate LHS and fraction on RHS Re-arrange for Ea Evaluate convert to kJ mol–1 If only k1 and k2 reversed this gives a negative answer for Ea Lose M1 and M5 If AE in M2 allow ECF Allow ECF from M4 to M5 for a correct unit conversion Allow range 66.3 – 67.1 M1 M2 M3 M4 M5 (5 x AO2) MARK SCHEME – A-LEVEL CHEMISTRY – 7405/2 – JUNE 2022 14 Question Answers Additional Comments/Guidelines Mark 01.8 Nucleophilic Addition ALLOW negative charge anywhere on cyanide But attacking lone pair must be on C Do not award M3 without attempt of M2 Allow M2 for attack to a positive carbon following breaking of C=O Penalise covalent KCN in M2 M3 ignore partial charges unless wrong Penalise M3 for incorrect connection between CN and C NB Allow fully displayed or other structural formulae

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AQA A-Level CHEMISTRY 7405/2 Paper 2 Organic
and Physical Chemistry Mark scheme June 2022

,A-level
CHEMISTRY
7405/2
Paper 2 Organic and Physical Chemistry
Mark scheme
June 2022
Version: 1.0 Final

, MARK SCHEME – A-LEVEL CHEMISTRY – 7405/2 – JUNE 2022



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.

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 examination
paper.


Further copies of this mark scheme are available from aqa.org.uk

, MARK SCHEME – A-LEVEL CHEMISTRY – 7405/2 – JUNE 2022



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.
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