Edexcel International A Level (IAL) Chemistry (WCH11–WCH16) Past Papers 2026

Structure, Bonding and Introduction to Organic Chemistry (WCH11)

Duration: 1h 30m

Energetics, Group Chemistry, Halogenoalkanes and Alcohols (WCH12)

Duration: 1h 30m

Practical Skills in Chemistry I (WCH13)

Duration: 1h 20m

Rates, Equilibria and Further Organic Chemistry (WCH14)

Duration: 1h 45m

Transition Metals and Organic Nitrogen Chemistry (WCH15)

Duration: 1h 45m

Practical Skills in Chemistry II (WCH16)

Duration: 1h 20m

Curly arrows in nucleophilic substitution (SN1 vs SN2 mechanisms)

WCH12 2023: 'Many answers indicated a lack of clarity about the significance of the curly arrow which should originate either from a covalent bond or from a lone pair.' WCH12 2024: lone pairs and bond-centre starting points are routinely missing.

Unit 2, Unit 4

Lattice energy — definitions, Born-Haber cycles and degree of covalency

WCH14 2023: candidates frequently confused 'atomic radius of iodide ions' (should be 'ionic radius'); polarisability vs ability to polarise was reversed; 'Common errors included omitting the negative sign, forgetting that two chloride ions were involved (despite this being shown in the cycle), incorrectly transcribed numbers and arithmetical errors.'

Unit 4

Redox half-equations and balancing electrons

WCH15 2023 examiner comment: 'This question was surprisingly poorly answered suggesting that many candidates do not understand how to construct half-equations for redox reactions.' Candidates routinely left HNO₃ undissociated despite the 'ionic' instruction.

Unit 5

Entropy explanations — bond strengths and surroundings

WCH14 2024: 'Many candidates did not understand that this question was asking them to state why the reaction was exothermic, and to do so in terms of bond breaking and bond making.' Most candidates linked entropy to physical states rather than to the number of moles or ways of arranging energy.

Unit 4

Ecell feasibility and electrochemical cell explanations

WCH15 2024: mean mark 1.8/6. 'Only the best candidates appreciated that the Cr²⁺ would be oxidised in air and so this was also true in part (iii) and so the solution would become more green due to the changing concentrations and the positive Ecell value when the cell was left running. The poor outcomes on this question indicate that candidates do not fully appreciate the factors that affect electrochemical cells or why they produce current.'

Unit 5

Drawing rate graphs — best-fit CURVES (not lines) and tangents at t = 0

WCH14 2023: 'Q18(a)(i) proved far more challenging to candidates than anticipated, with many drawing a straight line of best fit rather than the anticipated curve.' WCH14 2024: 'A surprisingly large proportion of candidates did not realise they needed to draw a tangent to the curve at t = 0 in order to determine the initial rate.'

Unit 4

Practical observations using approved IAL language

WCH13 2024: 'Remember that an observation is normally something that can be seen.' Candidates wrote 'gas given off' without effervescence, used 'limewater turns milky' instead of 'white precipitate', and stated 'precipitate dissolves' without giving the resulting solution colour.

Unit 3, Unit 6

Drawing organic structures — displayed vs structural vs skeletal, and the CHO group

WCH16 2024: 'the most common error was where the candidate correctly stated the test identified an aldehyde but then gave the wrong formula of COH instead of CHO.' WCH15 2023: 'When using structural formulae, aldehydes must be represented as RCHO. Do not use molecular formulae to represent organic structures unless instructed to do so.'

Unit 5, Unit 6