0620 · Cambridge IGCSE
0620/41
Theory (Extended)
Chemistry · June 2023 · Variant 1
Relative difficulty
Analysis source: Cambridge Assessment International Education
Analysis aligned to the official syllabus and assessment design.
3.8 / 5
160
180 min
Electrolysis and redox half-equations
Cohort performance
Session statistics from official examination reports
Total marks
160
Duration
180 min
Session difficulty
3.8 / 5
Key examiner messages
Top priorities from the principal examiner before you revise
The May/June 2023 examination papers across both core and extended tiers evaluate fundamental chemical principles, atomic theory, quantitative relationships, practical design, and organic structures.
Extended papers highlight challenging applications of electrolysis, polymer representation, and multi-step salt preparations, demanding precise chemical terminology.
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.
AO1 - Knowledge w
Weight: 4100%Knowledge wAO2 -
Weight: 375%Handling inAO3 -
Weight: 250%Experimental
Weight: 125%
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
Cambridge Principal Examiner Report — component performance and international standards
Level A*
Approx. 79% of maximum mark
Level A
Approx. 65% of maximum mark
Level B
Approx. 50% of maximum mark
Level C
Approx. 36% of maximum mark
Level D
Approx. 31% of maximum mark
Level E
Approx. 26% 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.
Match the expected response style for “State” questions.
Give reasons and link mechanism to outcome; each point needs a because/so chain.
State features in sequence or list observable properties — do not explain causes unless asked.
Match the expected response style for “Draw” questions.
Match the expected response style for “Deduce” questions.
Time traps
Sections where candidates spent disproportionate time relative to marks
Min per mark: 1.3
Min per mark: 1.1
Min per mark: 1
Syllabus traceability
Topics linked to questions and mark weighting in this session
Electrolysis
10 marks this session
Atomic structure and the Periodic Table
9 marks this session
Rate of reaction
8 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
Reversible reactions and equilibrium
Electrolysis
Atomic structure and the Periodic Table
Rate of reaction
Preparation of salts
Group VII properties
Difficulty trend
How session difficulty has shifted across recent years
Paper comparison
Marks and duration breakdown across papers in this session
Paper 21 (MCQ Extended):
Paper 41 (Theory Extended):
Paper 61 (Alternative to Practical):
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
Electrolysis
10 marks this session
Practise in RevuiAtomic structure and the Periodic Table
9 marks this session
Practise in RevuiRate of reaction
8 marks this session
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
The May/June 2023 examination papers across both core and extended tiers evaluate fundamental chemical principles, atomic theory, quantitative relationships, practical design, and organic structures.
- 2Message
Extended papers highlight challenging applications of electrolysis, polymer representation, and multi-step salt preparations, demanding precise chemical terminology.
Teacher briefing pack
One-page session summary for tutors and classroom review
June 2023 2023
Chemistry
The May/June 2023 examination papers across both core and extended tiers evaluate fundamental chemical principles, atomic theory, quantitative relationships, practical design, and organic structures. Extended papers highlight challenging applications of electrolysis, polymer repr
The May/June 2023 examination papers across both core and extended tiers evaluate fundamental chemical principles, atomic theory, quantitative relationships, practical design, and organic structures.
Extended papers highlight challenging applications of electrolysis, polymer representation, and multi-step salt preparations, demanding precise chemical terminology.
- Total marks
- 160
- Duration
- 180 min
- Session difficulty
- 3.8 / 5
Session analysis
The May/June 2023 examination papers across both core and extended tiers evaluate fundamental chemical principles, atomic theory, quantitative relationships, practical design, and organic structures. Extended papers highlight challenging applications of electrolysis, polymer representation, and multi-step salt preparations, demanding precise chemical terminology.
Updated Jun 13, 2026
Paper breakdown
Paper 21 (MCQ Extended):
Paper 41 (Theory Extended):
Paper 61 (Alternative to Practical):
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.
78% 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 Descriptive
50·28·63%
Chemical Equations
18·6·23%
Calculations
12·3·15%
Study ROI
Bigger bubbles recur more often; higher bubbles carry more marks, helping you rank revision priorities.
Time vs marks
Compare marks with suggested time allocation to plan exam pacing.
Core and basic reca
0.78 m/minDeductions and equa
1.00 m/minCalculations and mu
0.90 m/minTotal marks
73
Total time
82 min
Avg pace
0.89
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.
Next-year prediction
Topics worth watching next year, with the reason shown directly below each bar.
The mole and stoichiometry
90%90%
Reversible reactions and equilibrium
85%85%
Carboxylic acids and esters
80%80%
Exam tips
Paper format
- Duration
- 1h 15min
- Total marks
- 80
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.