AQA IAS-Level · Analysis & Prediction

2024 AQA IAS-Level Chemistry (9620) Past Paper Analysis

The January 2024 Oxford AQA International AS and A-Level Chemistry series presented a balanced but challenging set of papers. Unit 1 focused heavily on amount of substance, Group 2, and bonding; Unit 2 put significant weight on alcohols, halogenoalkane mechanisms, and equilibria; while Unit 3 tested advanced transition metal chemistry, multi-step pH/buffer calculations, and complex thermodynamics (Born-Haber and hydration cycles).

Updated: 12 Jun 2026

Analysis Sample paper

Difficulty 3.8/5

Total marks

220

Duration

270 mins

Most tested

Organic Oxidation & Mechanisms, Energetics (Born-Haber & Cycles), and Quantitative pH Calculations

Paper breakdown

Unit 1: Inorganic 1 and Physical 1 (CH01): 70 marks · 90 minsUnit 2: Organic 1 and Physical 1 (CH02): 70 marks · 90 minsUnit 3: Inorganic 2 and Physical 2 (CH03): 80 marks · 90 mins

Top chapters

Alcohols (Organic chemistry) · 23 marksEnergetics (Physical chemistry) · 20 marksAmount of substance (Physical chemistry) · 18 marks

Overall Difficulty Verdict

The January 2024 series sits at a solid 3.8 out of 5 in terms of difficulty. While Unit 1 (CH01) and Unit 2 (CH02) offered accessible entry-level questions on basic metallic bonding, periodicity trends, and standard mechanism templates, the paper profiles shifted quickly into high-algebraic demand. In particular, the Time-of-Flight (TOF) calculations in Unit 1, the percentage yield and purity problems in Unit 2, and the sophisticated weak acid-buffer titration calculations in Unit 3 tested the limits of students' mathematical precision and unit conversion skills.

Where the Marks Are Won and Lost

A substantial proportion of marks (~40%) was concentrated in three core areas: Amount of Substance (Titrations), Thermodynamic Cycles (Born-Haber & Hess's law), and Organic Reaction Mechanisms. In Unit 3, the multi-step titration calculation and the subsequent buffer pH calculation alone accounted for a large chunk of the paper's difficulty weighting. Candidates who systematically tracked stoichiometry, dilutions (e.g., transitioning from a 25.0 cm\(^3\) aliquot to a 250.0 cm\(^3\) volumetric flask), and handled unit conversions smoothly (e.g., converting density in g cm\(^{-3}\) to mol dm\(^{-3}\)) secured top-tier grades.

Examiner Pitfalls & Common Mistakes

Mechanism Geometry: Examiners frequently penalised candidates whose curly arrows did not originate precisely from a lone pair of electrons or from a covalent bond. Arrows starting from bare atoms or positive charges were marked incorrect.
State Symbols in Energetics: In the Born-Haber cycle for sodium oxide, omitting state symbols (particularly gaseous ions like \(2\text{Na}^+(\text{g})\)) or failing to double the ionisation energy of sodium was a common error that cost precious marks.
Acids & Bases Precision: A strict Oxford AQA rule is that all pH and \(\text{p}K_a\) values must be reported to exactly two decimal places. Many students lost marks by writing 4.8 or 13.2 instead of 4.84 or 13.24.
Solubility Misconceptions: In Unit 3, many candidates incorrectly labelled calcium hydroxide as a 'weak base' instead of explaining that its lower pH compared to barium hydroxide is due to its lower solubility in water.

Preparation Strategy & Upcoming Predictions

For the upcoming series, candidates must prioritise active recall of organic tests (Tollens’, Fehling’s, and acidified potassium dichromate colour changes) and practice drawing 3D transition metal complex shapes using precise wedge-and-dash representation. Additionally, expect a resurgence of questions on rate-determining steps and Arrhenius calculations, which were lighter in this series. Ensure you practice drawing complete, labeled hydrogen bonding diagrams with all partial charges (\(\delta^+\)/\(\delta^-\)) and lone pairs displayed, as these are easy marks that are frequently lost due to untidy drawing.

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.

Short Answer & Recall55 marks · 34 questions
Mechanisms & Diagrams45 marks · 18 questions
Calculations & Multi-step Problems120 marks · 22 questions

Mark accessibility

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

77%within easy or medium reach

105

easy: 65 marksmedium: 105 markshard: 50 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.

Alcohols Oxidation and Synthesis Yields

23 marks · Difficulty 2.5 · recurrence 5%

Born-Haber & Hess's Cycles

14 marks · Difficulty 3 · recurrence 5%

Ideal Gas and Titration Mathematics

18 marks · Difficulty 3.2 · recurrence 5%

Electrophiles and Nucleophiles Mechanisms

16 marks · Difficulty 3.5 · recurrence 5%

Acids, Bases & Buffer pH calculations

16 marks · Difficulty 4.5 · recurrence 4%

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.

Kinetics: Arrhenius Equation and Rate-Determining Steps85%

This series was relatively light on algebraic rate expressions and Arrhenius plots, which are staple high-mark questions in Unit 3.

Organic Analysis: Mass Spectrometry & NMR fragmentation80%

Only simple IR stretch recognition was tested this series. Expect a deeper multi-spectral identification puzzle next season.

Inorganic: Periodicity trends of Period 3 oxides reaction with water/acids75%

Always highly active, basic trend explanations are due to pivot back to reactions of Period 3 oxides (Na2O, P4O10, SO3) with water.

Topic-year heatmap

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

Jan 2023

Jun 2023

Jan 2024

Amount of substance (Physical chemistry)

Thermodynamics (Physical chemistry)

Periodicity (Inorganic chemistry)

Acids, bases and pH (Physical chemistry)

Bonding (Physical chemistry)

Energetics (Physical chemistry)

Group 7(17), the halogens (Inorganic chemistry)

Reactions of metal ions in aqueous solution (Inorganic chemistry)

Halogenoalkanes (Organic chemistry)

Transition metals and coordination complexes (Inorganic chemistry)

Examiner insights

Official report

Common pitfalls

Failing to convert standard parameters in TOF mass spec: forgetting to convert atomic mass in g mol-1 to mass of one single ion in kg, or wrong velocity substitutions.
Drawing curly arrows that start from the wrong focus point (must originate strictly from a lone pair or the center of a bond).
Omitting state symbols in ionisation energy equations or the Born-Haber cycle levels.
Writing pH values to only 1 decimal place, violating the strict 2 decimal places requirement for AQA A-Level.

Misconceptions

Describing calcium hydroxide as a 'weak base' rather than pointing out that its lower alkalinity relative to barium hydroxide is a function of its lower solubility.
Confusing the role of a catalyst at equilibrium (which accelerates the rate of both forward and reverse reactions equally) with shifting the position of the equilibrium.
Believing that adding distilled water to wash down the sides of the conical flask changes the titration moles (it does not change the amount of acid or base inside the flask).

Where marks are lost

Missing the dilution factor of 10 (25.0 cm3 to 250 cm3) in titration calculation steps.
Incorrect charge balances in the ligand substitution equations (e.g. [Fe(H2O)6]2+ reacting with EDTA4- to yield [Fe(EDTA)]2-).
Unfinished propagation steps in free-radical substitution: leaving out the radical dots on intermediate carbon species.

Estimated grade cut-off

Updated: 12 Jun 2026

Source: Oxford AQA International grade boundaries (UMS)

Level	Mark	Percentage
A	—	80%
B	—	70%
C	—	60%
D	—	50%
E	—	40%

Official grade boundaries published by Oxford AQA International grade boundaries (UMS).

Know what the examiners want — now go get those marks

Thinka is an AI practice app used by 100,000+ DSE students to drill questions and get instant feedback on every answer. You already know the high-frequency topics and where marks are lost — now practice those specifically on Thinka and turn this analysis into actual marks.

Start Practising Free See pricing

Know what's tested? Drill those topics on Thinka — AI questions, instant marking.

Start Practising Free