CHEMISTRY · Pearson Edexcel IGCSE
CHEMISTRY/22
C (Advanced Applications)
Chemistry · 2024 · Variant 2
Relative difficulty
Analysis source: Pearson Edexcel
Analysis aligned to the official syllabus and assessment design.
3.6 / 5
180
195 min
Chemical calculations and stoichiometry
Cohort performance
Session statistics from official examination reports
Total marks
180
Duration
195 min
Session difficulty
3.6 / 5
Key examiner messages
Top priorities from the principal examiner before you revise
As is customary with Edexcel, quantitative chemistry was the largest single source of marks.
Across both papers, calculations accounted for over 30% of the total marks.
This included standard relative formula mass calculations, more demanding gas-volume stoichiometry, and water of crystallisation derivations.
Students who had mastered systematic conversions (mass to moles, volume to moles) secured a solid foundation.
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 & Calculation
Weight: 7100%Chemical Explanation
Weight: 686%Practical Techniques
Weight: 457%Organic
Weight: 229%Synthesis & Physiological Explanation
Weight: 114%
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
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
Give reasons and link mechanism to outcome; each point needs a because/so chain.
Show formula, substitution, and unit; method marks need visible working.
Match the expected response style for “Give” questions.
Match the expected response style for “State” questions.
State features in sequence or list observable properties — do not explain causes unless asked.
Match the expected response style for “Show” questions.
Match the expected response style for “Predict” questions.
Time traps
Sections where candidates spent disproportionate time relative to marks
Min per mark: 2
Min per mark: 1.3
Min per mark: 1.1
Min per mark: 1.1
Min per mark: 1
Min per mark: 1
Syllabus traceability
Topics linked to questions and mark weighting in this session
Chemical formulae, equations and calculations
32 marks this session
Rates of reaction
21 marks this session
Energetics
19 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
Chemical formulae, equations and calculations
Energetics
Crude oil
Elements, compounds and mixtures
Alcohols
Reactivity series
Rates of reaction
Alkenes
Paper comparison
Marks and duration breakdown across papers in this session
Paper 1CR:
Paper 2CR:
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
Chemical formulae, equations and calculations
32 marks this session
Practise in RevuiRates of reaction
21 marks this session
Practise in RevuiEnergetics
19 marks this session
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
As is customary with Edexcel, quantitative chemistry was the largest single source of marks.
- 2Message
Across both papers, calculations accounted for over 30% of the total marks.
- 3Message
This included standard relative formula mass calculations, more demanding gas-volume stoichiometry, and water of crystallisation derivations.
- 4Message
Students who had mastered systematic conversions (mass to moles, volume to moles) secured a solid foundation.
Teacher briefing pack
One-page session summary for tutors and classroom review
2024 2024
Chemistry
As is customary with Edexcel, quantitative chemistry was the largest single source of marks. Across both papers, calculations accounted for over 30% of the total marks. This included standard relative formula mass calculations, more demanding gas-volume stoichiometry, and water o
As is customary with Edexcel, quantitative chemistry was the largest single source of marks.
Across both papers, calculations accounted for over 30% of the total marks.
This included standard relative formula mass calculations, more demanding gas-volume stoichiometry, and water of crystallisation derivations.
- Total marks
- 180
- Duration
- 195 min
- Session difficulty
- 3.6 / 5
Session analysis
As is customary with Edexcel, quantitative chemistry was the largest single source of marks. Across both papers, calculations accounted for over 30% of the total marks. This included standard relative formula mass calculations, more demanding gas-volume stoichiometry, and water of crystallisation derivations. Students who had mastered systematic conversions (mass to moles, volume to moles) secured a solid foundation.
Updated Jun 13, 2026
Paper breakdown
Paper 1CR:
Paper 2CR:
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.
83% 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.
Structured Short Answer
70·50·39%
Extended Explanation
60·20·33%
Calculations
45·15·25%
Multiple Choice
(MCQ)
5·5·3%
Study ROI
Bigger bubbles recur more often; higher bubbles carry more marks, helping you rank revision priorities.
Difficulty trend
Compare difficulty across recent years.
Time vs marks
Compare marks with suggested time allocation to plan exam pacing.
Paper 1CR - Early R
0.50 m/minPaper 1CR - Practic
0.96 m/minPaper 1CR - Advance
0.77 m/minPaper 2CR - Foundat
0.88 m/minPaper 2CR - Organic
0.88 m/minPaper 2CR - Electro
0.96 m/minTotal marks
121
Total time
141 min
Avg pace
0.86
Next-year prediction
Topics worth watching next year, with the reason shown directly below each bar.
Group 7 (halogens) – chlorine, bromine and iodine
90%90%
Synthetic polymers
85%85%
Carboxylic acids
80%80%
States of matter
75%75%
Examiner notes & key calculations
- Molar Enthalpy Signs: In the ethanol combustion question, several students calculated the correct magnitude but omitted the negative sign for the exothermic reaction, losing a vital mark. Always write ΔH=−720 kJ/mol \Delta H = -720\text{ kJ/mol} ΔH=−720 kJ/mol explicitly.
- State Symbols: Simple errors, such as forgetting to include gaseous state symbols for diatomic molecules (like O2(g) \text{O}_2(g) O2(g)), cost easy marks in chemical equations.
- Bonding Definitions: When defining covalent bonding, describing the attraction between shared electrons and 'the nucleus' (singular) was rejected. Covalent bonding involves attraction to both nuclei (plural).
- Catalyst Misunderstandings: In the reversible reaction question, a common misconception was that adding a catalyst increases the yield of ethanol. Remember, catalysts increase the rate of both forward and reverse reactions equally, leaving the equilibrium position and yield unchanged.
Exam tips
Paper format
- Duration
- 1h 15min
- Total marks
- 70
- Weighting
- 38.9%
- Question types
- Multiple Choice, Recall tables & diagrams, Multi-step physical calculation (bond energies, yields), Experimental design and evaluation
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.