AqA EXAMPRO
A-LEVEL CHEMISTRY MARK SCHEME
Practice Paper 2 Maximum marks: 101
View detailed guidance on the conclusions you can draw from your students' performance in
these papers on the MERiT welcome page. Understand how your students compare with
others and target revision effectively by entering marks into MERiT.
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.
Page 2
A-LEVEL CHEMISTRY MARK SCHEME
Practice Paper 2 Maximum marks: 101
View detailed guidance on the conclusions you can draw from your students' performance in
these papers on the MERiT welcome page. Understand how your students compare with
others and target revision effectively by entering marks into MERiT.
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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