Cambridge IAS-Level · Analysis & Prediction

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

This analysis covers the Cambridge International AS Level Chemistry (9701) October/November 2023 series (Paper 12 and Paper 22). It reveals key performance discriminators, structural blueprint weights, examiner-sourced pitfalls, and strategic advice for achieving high marks.

Updated: 12 Jun 2026

Analysis Sample paper

Difficulty 3.8/5

Total marks

100

Duration

150 mins

Most tested

Equilibria and Periodicity of Period 3 Elements

Paper breakdown

Paper 12 (Multiple Choice): 40 marks · 75 minsPaper 22 (AS Level Structured): 60 marks · 75 mins

Top chapters

Equilibria (Physical chemistry (AS Level)) · 7 marksIonisation energy (Atomic structure) · 6 marksSimilarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds (Group 2) · 6 marksPeriodicity of physical properties of the elements in Period 3 (The Periodic Table: chemical periodicity) · 5 marksHydrocarbons (Organic chemistry (AS Level)) · 5 marks

Difficulty Verdict & Performance Profile

The October/November 2023 series represented a highly discriminating set of papers. Paper 12 (Multiple Choice) balanced classical calculations with deep stereochemical identification, while Paper 22 (AS Structured Questions) tested core physical trends and multi-stage organic transformations. Average students struggled with exact definitions and multi-step stoichiometric pathways, whereas top candidates distinguished themselves through accurate equation-writing with state symbols and precise mechanism details.

Where the Marks are Won

In the physical chemistry sections, major marks are concentrated in Equilibria (specifically calculating partial pressures and setting up \( K_p \) expressions) and Ionisation Energies (explaining the phosphorus-sulfur anomaly). In organic chemistry, the core marks reside in drawing multi-step synthesis pathways (from propene/ethanal to lactic and pyruvic acids) and accurate curly arrow representation of electrophilic additions.

Examiner Pitfalls & Misconceptions

State Symbols: Candidates frequently lost marks by omitting gas phase symbols \( (g) \) in equations representing the first ionisation energy.
Weak Acid Definition: A persistent misconception was describing a weak Brønsted-Lowry acid as a substance that 'does not completely dissolve' rather than 'partially dissociates' in aqueous solution.
Inductive Effects: When explaining the stability of carbocation intermediates, many candidates loosely quoted Markovnikov's rule rather than explicitly discussing positive inductive effects of alkyl groups.
Error Propagation: In practical-based structured questions, students failed to double the single-reading uncertainty value when calculating percentage errors for temperature differences.

Preparation Strategy & Prediction

To master future papers, candidates must practice writing fully balanced equations for all inorganic thermal decompositions (particularly Group 2 nitrates and carbonates) and memorise a robust reagent-condition matrix for organic functional groups. Spectroscopic correlation (matching Infrared wavenumbers with Mass Spectrometry parent/daughter peaks) is highly predicted to remain a core barrier to top grades in subsequent series.

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.

MCQ40 marks · 40 questions
Structured60 marks · 4 questions

Mark accessibility

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

80%within easy or medium reach

easy: 35 marksmedium: 45 markshard: 20 marks

Difficulty trend

Compare difficulty across recent years.

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.

Equilibria (AS Level)

7 marks · Difficulty 3.5 · recurrence 5%

Group 2 Metals

6 marks · Difficulty 2.5 · recurrence 5%

Period 3 Trends (Periodicity)

10 marks · Difficulty 3 · recurrence 5%

First Ionisation Energy

6 marks · Difficulty 2.8 · recurrence 4%

Hydrocarbons (Alkenes & Alkanes)

5 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.

Organic Synthesis Reagents and Conditions92%

Many candidates struggled with multi-stage synthesis steps in recent series, making it highly probable for upcoming sets.

Infrared and Mass Spectrometry interpretation90%

Continual focus on correlating analytical spectra with structural deduction of organic compounds.

Group 2 Carbonate & Nitrate Thermal Decomposition85%

Tested consistently to evaluate trends in cationic polarising power.

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.

Topic-year heatmap

Compare topic weight by year to spot recurring and returning areas.

Jun 2023 (V1)

Jun 2023 (V2)

Jun 2023 (V3)

Nov 2023 (V1)

Nov 2023 (V2)

Atomic structure (Physical chemistry (AS Level))

Electrons, energy levels and atomic orbitals

Ionisation energy

Particles in the atom and atomic radius

Atoms, molecules and stoichiometry (Physical chemistry (AS Level))

Relative masses of atoms and molecules

Reacting masses and volumes

The gaseous state: ideal and real gases and pV = nRT

Formulas

Shapes of molecules

Examiner insights

Official report

Common pitfalls

Omitting gas state symbols (g) when constructing equations for the first ionisation energy.
Failure to double the error margin for thermometer readings where a temperature difference is measured (using 0.1 instead of 0.1 x 2).
Drawing five-valent carbon atoms in organic structures (especially when drawing polymers or intermediates).
Using crude or imprecise terminology like 'soluble precipitate' or stating that 'water did not dissolve' instead of 'partially dissociates' for weak acids.

Misconceptions

Believing that adding an inert gas at constant volume shifts the equilibrium position or affects reaction rates.
Assuming that a weak acid has low solubility or 'does not completely dissolve' rather than 'partially dissociates'.
Describing basicity by saying a lone pair 'attracts' a proton, instead of describing the availability of the lone pair to be 'donated' to form a dative covalent bond.

Where marks are lost

Failing to write down the formula of products correctly (e.g., using (CH3COO)Ba instead of (CH3COO)2Ba).
Inability to deduce the molecular formula from the M and M+1 mass spectrometry peaks.
Neglecting acid conditions when specifying oxidising agents like acidified K2Cr2O7.
Incorrect curly arrow starting points (e.g., from the hydrogen atom rather than from the covalent bond or lone pair in mechanism diagrams).

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