9620 · Oxford AQA International AS Level
9620/21
Paper 2
Chemistry · 2024 · Variant 1
Relative difficulty
Analysis source: Oxford AQA
Analysis aligned to the official syllabus and assessment design.
3.8 / 5
220
270 min
Organic Oxidation & Mechanisms, Energetics (Born-Haber & Cycles), and Quantitative pH Calculations
Cohort performance
Session statistics from official examination reports
Total marks
220
Duration
270 min
Session difficulty
3.8 / 5
Key examiner messages
Top priorities from the principal examiner before you revise
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.
Question difficulty map
How candidates performed on each question in this series
No data available in official reports
Assessment objectives
Skill and AO weighting from official examiner commentary
Skill weighting
Shows the skill mix this paper tested most heavily.
Mathematical
Weight: 8100%Organic
Weight: 788%Reaction
Weight: 675%Factual
Weight: 563%Recall & Understanding
Weight: 450%Thermodynamic & E
Weight: 338%Chemical Structure
Weight: 225%
Method marks watchlist
Where working, steps, or method marks were commonly lost
No data available in official reports
Recurring mistakes across years
Themes examiners flag in multiple recent sessions for this subject
No data available in official reports
Question choice intelligence
Mean scores and popularity for optional questions (HKDSE electives)
No data available in official reports
Level exemplars
What candidate scripts at each grade level looked like
No data available in official reports
Grade & admission context
How marks relate to grade thresholds and entry standards
Report type
Examiner report — national grade boundaries and question-level commentary
Level A
Approx. 80% of maximum mark
Level B
Approx. 70% of maximum mark
Level C
Approx. 60% of maximum mark
Level D
Approx. 50% of maximum mark
Level E
Approx. 40% of maximum mark
Deep insights
What top candidates did
Techniques and approaches examiners rewarded in this series
No data available in official reports
Command word playbook
How to match each command word to the expected response style
Show formula, substitution, and unit; method marks need visible working.
Give reasons and link mechanism to outcome; each point needs a because/so chain.
Match the expected response style for “Name” questions.
State features in sequence or list observable properties — do not explain causes unless asked.
Match the expected response style for “Deduce” questions.
Time traps
Sections where candidates spent disproportionate time relative to marks
No data available in official reports
Syllabus traceability
Topics linked to questions and mark weighting in this session
Alcohols (Organic chemistry)
23 marks this session
Energetics (Physical chemistry)
20 marks this session
Amount of substance (Physical chemistry)
18 marks this session
MCQ trap analytics
Commonly chosen wrong options from examiner commentary
No data available in official reports
Topic heatmap across years
Mark concentration by topic and exam year for this subject
Mark intensity
Amount of substance
Transition metal chemistry
Alcohols (Organic chemistry)
Thermodynamics
Energetics (Physical chemistry)
Oxidation, reduction and redox equations
Amount of substance (Physical chemistry)
Periodicity
Difficulty trend
How session difficulty has shifted across recent years
Paper comparison
Marks and duration breakdown across papers in this session
Unit 1: Inorganic 1 and Physical 1 (CH01): Unit 2: Organic 1 and Physical 1 (CH02): Unit 3: Inorganic 2 and Physical 2 (CH03):
Marks you can still earn
Where valid approaches outside the mark scheme may still gain credit
No data available in official reports
Practise what examiners flagged
Target weak topics from this report inside the Revui app
Alcohols (Organic chemistry)
23 marks this session
Practise in RevuiEnergetics (Physical chemistry)
20 marks this session
Practise in RevuiAmount of substance (Physical chemistry)
18 marks this session
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
The January 2024 series sits at a solid 3.8 out of 5 in terms of difficulty.
- 2Message
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.
- 3Message
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.
Teacher briefing pack
One-page session summary for tutors and classroom review
2024 2024
Chemistry
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 hig
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.
- Total marks
- 220
- Duration
- 270 min
- Session difficulty
- 3.8 / 5
Session analysis
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.
Updated Jun 12, 2026
Paper breakdown
Unit 1: Inorganic 1 and Physical 1 (CH01): Unit 2: Organic 1 and Physical 1 (CH02): Unit 3: Inorganic 2 and Physical 2 (CH03):
Top chapters
Exam structure insights
Marks by chapter
See where the marks were concentrated so revision time goes to the highest-value topics.
Mark accessibility
Estimate which marks were basic, mid-level, or high-difficulty.
77% within easy or medium reach
Command word frequency
Spot common command words so answers match the expected response style.
Question type mix
Compare the mark share of each paper section and question type.
Calculations & Multi-step Problems
120·22·55%
Short Answer & Recall
55·34·25%
Mechanisms & Diagrams
45·18·20%
Study ROI
Bigger bubbles recur more often; higher bubbles carry more marks, helping you rank revision priorities.
Next-year prediction
Topics worth watching next year, with the reason shown directly below each bar.
Kinetics: Arrhenius Equation and Rate-Determining Steps
85%85%
Organic Analysis: Mass Spectrometry & NMR fragmentation
80%80%
Inorganic: Periodicity trends of Period 3 oxides reaction with water/acids
75%75%
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.
Examiner notes & key calculations
- 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 2Na+(g)2\text{Na}^+(\text{g})2Na+(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 pKa\text{p}K_apKa 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.
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.