Cambridge IAS-Level · Analysis & Prediction

2023 Cambridge IAS-Level Chemistry (9701) Past Paper Analysis

An analysis of the May/June 2023 Chemistry (9701) Paper 11, 21, and 31 exams highlights a high demand for precise definitions, flawless stoichiometric calculations, and meticulous qualitative observations.

Updated: 12 Jun 2026

Analysis Sample paper

Difficulty 3.5/5

Total marks

140

Duration

270 mins

Most tested

Reaction kinetics (AS Level)

Paper breakdown

Paper 11 (Multiple Choice): 40 marks · 75 minsPaper 21 (AS Level Structured): 60 marks · 75 minsPaper 31 (Advanced Practical): 40 marks · 120 mins

Top chapters

Reaction kinetics (Physical chemistry (AS Level)) · 18 marksChemistry of transition elements (Inorganic chemistry (A Level)) · 12 marksAlkanes (Hydrocarbons) · 9 marks

Difficulty Verdict

The May/June 2023 Chemistry (9701) series presented a challenging yet balanced suite of papers. Paper 11 (Multiple Choice) pushed candidates to apply concepts in unfamiliar contexts, with several questions proving highly challenging. Paper 21 (Structured Questions) demanded rigorous, exact definitions and strict adherence to organic mechanism rules, while Paper 31 (Practical) tested candidates' patience with multi-step thermometric calculations and strict qualitative terminology. Overall, the papers are classified at a moderate-to-high difficulty.

Where the Marks Are

A significant portion of the marks was concentrated in Reaction Kinetics and Organic Synthesis. In Paper 21, Question 4 and 5 required candidates to trace complex reaction pathways and deduce unknown structures (such as pentan-2-ol and methyl decanoate) from a sequence of chemical tests. In Paper 31, a massive 17 marks were allocated to the clock reaction kinetics practical, where drawing a perfect line of best fit and calculating rates accounted for key differentiation. Transition element chemistry also held substantial weight, particularly through qualitative analysis of copper and zinc complexes in the practical component.

Examiner Pitfalls

The principal examiner reports highlighted several critical areas where even high-achieving students lost easy marks:

Precise Definitions: Many candidates defined the enthalpy change of neutralisation without specifying "per mole of water formed" or omitting references to the standard molar scale.
Calorimetry Errors: In calculations involving \( Q = mc\Delta T \), candidates frequently used the mass of the solid magnesium or salt rather than the mass of the solution (e.g., 25.0g), a recurring error across multiple series.
Rounding and Sig Figs: Rounding intermediate steps too early led to catastrophic cumulative errors in the multi-step Hess's Law cycles.
Mechanism Accuracy: In free-radical substitution and nucleophilic addition mechanisms, curly arrows frequently failed to start exactly at a lone pair or bond, or pointed to the wrong destination.

Strategy for Success

To master upcoming sessions, students must treat state symbols as non-negotiable in all chemical equations, particularly when describing precipitation reactions like \( \text{BaSO}_4\text{(s)} \). When studying atomic structure and periodicity, ensure the concept of shielding is understood as remaining relatively constant across a period. Finally, do not truncate relative atomic masses from the Periodic Table to integers; always use the exact decimal values provided in the exam insert.

Future Predictions

Given the low success rate in the 2023 series regarding enthalpy of neutralisation calculations and alkene stereoisomerism, these areas are highly likely to be targeted in upcoming cycles. Additionally, expect a stronger emphasis on Group 2 solubility trends and thermal decomposition kinetics, which were only lightly tested in Paper 11.

Charts

Marks by chapter

See where the marks were concentrated so revision time goes to the highest-value topics.

Question type mix

Compare the mark share of each paper section and question type.

Multiple Choice40 marks · 40 questions
Structured60 marks · 5 questions
Practical40 marks · 3 questions

Mark accessibility

Estimate which marks were basic, mid-level, or high-difficulty.

75%within easy or medium reach

easy: 42 marksmedium: 63 markshard: 35 marks

Command word frequency

Spot common command words so answers match the expected response style.

Skill weighting

Shows the skill mix this paper tested most heavily.

Study ROI

Bigger bubbles recur more often; higher bubbles carry more marks, helping you rank revision priorities.

Reaction kinetics (AS Level)

18 marks · Difficulty 2.8 · recurrence 5%

Alkanes (Hydrocarbons)

9 marks · Difficulty 2.2 · recurrence 5%

Hydroxy compounds (AS Level)

8 marks · Difficulty 2.5 · recurrence 5%

Periodicity of chemical properties (Period 3)

8 marks · Difficulty 2.4 · recurrence 4%

Enthalpy change, ΔH

6 marks · Difficulty 3.2 · recurrence 5%

Time vs marks

Compare marks with suggested time allocation to plan exam pacing.

marksmins

Next-year prediction

Topics worth watching next year, with the reason shown directly below each bar.

Standard enthalpy of neutralisation vs solution90%

Given massive pitfalls in using solution mass in Q=mcΔT calculations, examiners will continue to test neutralisation cycles to ensure students have corrected this common error.

Organic stereoisomerism in cyclic systems85%

Stereoisomerism is highly tested at AS Level, but complex ring-derived isomer calculations showed low accuracy in MCQ series, indicating a high focus in upcoming papers.

Group 2 carbonates thermal stability80%

A cornerstone of inorganic periodicity trends which was briefly featured in the MCQ paper but is overdue for a full structured question in Paper 2.

Cumulative marks ladder

The line is your running mark total question by question; dashed lines are the estimated grade cut-offs. See which question the line crosses your target grade at, so you know how far you must answer cleanly and which questions decide a band.

Examiner insights

Official report

Common pitfalls

Failing to state 'per mole of water formed' in the definition of enthalpy change of neutralisation, instead referring simply to 'one mole of acid and base'.
Using the mass of the solid (e.g., magnesium or salt) instead of the mass of the solution (usually 25.0g) in Q = mcΔT equations during practical exams.
Omitting or incorrectly writing state symbols in balanced equations, especially for precipitate products like BaSO4(s).
Rounding numbers too early in multi-step calculations, which compounded errors and led to final answers outside the accepted range.

Misconceptions

Believing that the shielding effect increases or decreases significantly across a single period, rather than remaining relatively constant.
Confusing 'nucleon number' with 'neutron number' or 'isotope' with 'isomer'.
Thinking that neutralisation reactions require an initial input of energy or that all neutralisations have identical energy values regardless of acid/base strength.
Confusing the color of solutions with precipitates, e.g., describing the addition of a solid as forming a 'cloudy' solution instead of a 'precipitate'.

Where marks are lost

Failing to draw curly arrows starting exactly from a lone pair or a bond, and ending exactly at the target atom or bond in mechanisms.
Inability to construct correct ionic equations, frequently omitting state symbols or failing to balance charges.
Omitting the conditions (e.g., UV light for alkane substitution, heat/reflux for hydrolysis) or using imprecise reagents like 'aqueous Ba2+' instead of 'barium chloride'.
Incorrectly identifying the limiting reagent in volumetric stoichiometry calculations, particularly when coefficients are 1:2.

Estimated grade cut-off

Updated: 12 Jun 2026

Source: Cambridge International component thresholds (AS aggregate, derived)

Level	Mark	Percentage
A	88/140	63%
B	74/140	53%
C	61/140	44%
D	49/140	35%
E	37/140	26%

Estimated cut-offs from Cambridge International component thresholds (AS aggregate, derived); may differ from the official boundaries.

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