AqA EXAMPRO A-LEVEL CHEMISTRY PRACTICE PAPER 2 MARK SCHEME SUMMER 2022 100% CORRECT.
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Course
A-LEVEL CHEMISTRY PRACTICE PAPER 2 MS
Institution
A-LEVEL CHEMISTRY PRACTICE PAPER 2 MS
Q1. (a) (i)M1 (Compounds / molecules with) the same structural formula2
Penalise M1 if ‘same structure’ or ‘different structural / displayed formula’.
M2 with atoms / bonds / groups arranged differently in space
OR atoms / bonds / groups with different spatial arrangements / different or...
aqa exampro a level chemistry practice paper 2 mark scheme summer 2022 100
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AqA EXAMPRO
A-LEVEL CHEMISTRY MARK SCHEME
Practice Paper 2 Maximum marks: 101
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Q1. (a) (i) M1 (Compounds / molecules with) the same structural formula 2
Penalise M1 if ‘same structure’ or ‘different structural / displayed
formula’.
M2 with atoms / bonds / groups arranged differently in space
OR atoms / bonds / groups with different spatial arrangements / different
orientation
Ignore references to ‘same molecular formula’ or ‘same
empirical formula’.
Mark independently.
(ii)
1
Credit C–H3C
Credit C2H5
Penalise C–CH3CH2
(b) M1 Br2 OR bromine (water) OR bromine (in CCl4 / organic solvent) 1
If M1, has no reagent or an incorrect reagent, CE=0.
Ignore ‘acidified’.
M2 Isomer 1: decolourised / goes colourless / loses its colour 1
For M1 penalise Br (or incorrect formula of other correct
reagent), but mark on.
M3 Isomer 2: remains orange / red / yellow / brown / the same OR no reaction / 1
no (observable) change OR reference to colour going to the cyclopentane layer
For M1, it must be a whole reagent and / or correct formula.
If oxidation state given in name, it must be correct. If
‘manganate’ OR ‘manganate(IV)’ or incorrect formula, penalise
M1, but mark on.
Alternatives : potassium manganate(VII)
M1 KMnO4 in acid M2 colourless M3 purple
M1 KMnO4 in alkali / neutral M2 brown solid M3 purple
Credit for the use of iodine
M1 iodine (solution / in KI) M2 colourless M3 (brown) to purple (credit no change)
Credit for the use of concentrated H2SO4
, M1 concentrated H2SO4 M2 brown M3 no change / colourless
Ignore ‘goes clear’.
Ignore ‘nothing (happens)’.
Ignore ‘no observation’.
No credit for combustion observations.
(c) (i) (Both infrared spectra show an absorption in range) 1620 to 1680 (cm−1) 1
Ignore reference to other ranges (eg for C–H or C–C).
(ii) The fingerprint (region) / below 1500 cm−1 will be different 1
or its fingerprinting
will be different
OR different absorptions / peaks are seen (in the region) below 1500 cm−1 (or a
specified region within the fingerprint range)
Allow the words ‘dip’ OR ‘spike’ OR ‘low transmittance’ as
alternatives for absorption.
QoL
(d) 1
All bonds must be drawn.
Ignore bond angles.
(e) (i) M1 Electrophilic addition 1
M1 both words needed.
Penalise one mark from their total if half-headed arrows are used.
M2 must show an arrow from the double bond towards the H atom of 1
the H–Br molecule
M2 Ignore partial negative charge on the double bond.
M3 must show the breaking of the H–Br bond 1
M3 Penalise incorrect partial charges on H–Br bond and
penalise formal charges.
M4 is for the structure of the tertiary carbocation 1
Penalise M4 if there is a bond drawn to the positive charge.
Penalise once only in any part of the mechanism for a line and
two dots to show a bond.
M5 must show an arrow from the lone pair of electrons on the negatively 1
charged bromide ion towards the positively charged carbon atom of
either a secondary or a tertiary carbocation
For M5, credit attack on a partially positively charged
carbocation structure but penalise M4.
Max 3 of any 4 marks in the mechanism for wrong organic reactant
or wrong organic product (if shown) or secondary carbocation.
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