CHEMISTRY-YCH11 · Pearson Edexcel International A Level
CHEMISTRY-YCH11/21
Paper 2
Chemistry · Winter 2025 · Variant 1
Relative difficulty
Analysis source: Pearson Edexcel
Analysis aligned to the official syllabus and assessment design.
3.6 / 5
440
550 min
Stoichiometry & Organic Reaction Mechanisms
Cohort performance
Session statistics from official examination reports
Total marks
440
Duration
550 min
Session difficulty
3.6 / 5
Key examiner messages
Top priorities from the principal examiner before you revise
The January 2025 Pearson Edexcel International Advanced Level (IAL) Chemistry suite (YCH11) presents a rigorous, mathematically demanding set of papers.
Testing both core theoretical foundations and advanced practical applications, the exams carried a strong calculation load.
Unit 5 (Transition Metals and Organic Nitrogen Chemistry) and Unit 4 (Rates, Equilibria and Further Organic Chemistry) stood out as the most challenging papers, featuring complex multi-step organic syntheses and multi-stage quantitative redox problems.
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: 5100%Mechanism drawing
Weight: 480%Experimental
Weight: 360%Theoretical
Weight: 240%Explanation
Weight: 120%
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. 90% of maximum mark
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 “Deduce” questions.
Match the expected response style for “State” questions.
Match the expected response style for “Draw” questions.
Name or point to the specific feature asked for — avoid extra explanation.
State features in sequence or list observable properties — do not explain causes unless asked.
Support your choice with specific evidence from data or the scenario given.
Time traps
Sections where candidates spent disproportionate time relative to marks
Min per mark: 2
Min per mark: 1.6
Min per mark: 1.6
Min per mark: 1.2
Min per mark: 1.2
Min per mark: 1.1
Syllabus traceability
Topics linked to questions and mark weighting in this session
Formulae, Equations and Amount of Substance
60 marks this session
Organic Chemistry: Carbonyls, Carboxylic Acids and Chirality
55 marks this session
Transition Metals and their Chemistry
55 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
Formulae, Equations and Amount of Substance
Transition Metals and their Chemistry
Organic Chemistry: Alcohols, Halogenoalkanes and Spectra
Organic Chemistry: Carbonyls, Carboxylic Acids and Chirality
Organic Nitrogen Compounds: Amines, Amides, Amino Acids and Proteins
Organic Synthesis
Kinetics (Rates, Equilibria and Further Organic Chemistry)
Bonding and Structure
Paper comparison
Marks and duration breakdown across papers in this session
WCH11/01 Unit 1: Structure, Bonding and Introduction to Organic Chemistry: WCH12/01 Unit 2: Energetics, Group Chemistry, Halogenoalkanes and Alcohols: WCH13/01 Unit 3: Practical Skills in Chemistry I: WCH14/01 Unit 4: Rates, Equilibria and Further Organic Chemistry: WCH15/01 Unit 5: Transition Metals and Organic Nitrogen Chemistry: WCH16/01 Unit 6: Practical Skills in Chemistry II:
Marks you can still earn
Where valid approaches outside the mark scheme may still gain credit
- Failure to show clear, step-by-step working in multi-step mole and percentage yield calculations, preventing partial credit.
Practise what examiners flagged
Target weak topics from this report inside the Revui app
Formulae, Equations and Amount of Substance
60 marks this session
Practise in RevuiOrganic Chemistry: Carbonyls, Carboxylic Acids and Chirality
55 marks this session
Practise in RevuiTransition Metals and their Chemistry
55 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 2025 Pearson Edexcel International Advanced Level (IAL) Chemistry suite (YCH11) presents a rigorous, mathematically demanding set of papers.
- 2Message
Testing both core theoretical foundations and advanced practical applications, the exams carried a strong calculation load.
- 3Message
Unit 5 (Transition Metals and Organic Nitrogen Chemistry) and Unit 4 (Rates, Equilibria and Further Organic Chemistry) stood out as the most challenging papers, featuring complex multi-step organic syntheses and multi-stage quantitative redox problems.
Teacher briefing pack
One-page session summary for tutors and classroom review
Winter 2025 2025
Chemistry
The January 2025 Pearson Edexcel International Advanced Level (IAL) Chemistry suite (YCH11) presents a rigorous, mathematically demanding set of papers. Testing both core theoretical foundations and advanced practical applications, the exams carried a strong calculation load. Uni
The January 2025 Pearson Edexcel International Advanced Level (IAL) Chemistry suite (YCH11) presents a rigorous, mathematically demanding set of papers.
Testing both core theoretical foundations and advanced practical applications, the exams carried a strong calculation load.
Unit 5 (Transition Metals and Organic Nitrogen Chemistry) and Unit 4 (Rates, Equilibria and Further Organic Chemistry) stood out as the most challenging papers, featuring complex multi-step organic syntheses and multi-stage quantitative redox problems.
- Total marks
- 440
- Duration
- 550 min
- Session difficulty
- 3.6 / 5
Session analysis
The January 2025 Pearson Edexcel International Advanced Level (IAL) Chemistry suite (YCH11) presents a rigorous, mathematically demanding set of papers. Testing both core theoretical foundations and advanced practical applications, the exams carried a strong calculation load. Unit 5 (Transition Metals and Organic Nitrogen Chemistry) and Unit 4 (Rates, Equilibria and Further Organic Chemistry) stood out as the most challenging papers, featuring complex multi-step organic syntheses and multi-stage quantitative redox problems.
Updated Jun 12, 2026
Paper breakdown
WCH11/01 Unit 1: Structure, Bonding and Introduction to Organic Chemistry: WCH12/01 Unit 2: Energetics, Group Chemistry, Halogenoalkanes and Alcohols: WCH13/01 Unit 3: Practical Skills in Chemistry I: WCH14/01 Unit 4: Rates, Equilibria and Further Organic Chemistry: WCH15/01 Unit 5: Transition Metals and Organic Nitrogen Chemistry: WCH16/01 Unit 6: Practical Skills in Chemistry II:
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.
75% 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
220·55·50%
practical
140·25·32%
multipleChoice
80·80·18%
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.
Unit 1: Structure,
0.50 m/minUnit 2: Energetics,
0.89 m/minUnit 3: Practical C
0.63 m/minUnit 4: Rates, Equi
0.86 m/minUnit 5: Transition
0.86 m/minUnit 6: Practical C
0.63 m/minTotal marks
380
Total time
500 min
Avg pace
0.76
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.
Kinetics (Arrhenius & Rate Equation)
95%95%
Redox Equilibria & Electrode Potentials
90%90%
Grignard Reagents and Carbon Chain Extension
85%85%
Executive Difficulty Verdict
The January 2025 Pearson Edexcel International Advanced Level (IAL) Chemistry suite (YCH11) presents a rigorous, mathematically demanding set of papers. Testing both core theoretical foundations and advanced practical applications, the exams carried a strong calculation load. Unit 5 (Transition Metals and Organic Nitrogen Chemistry) and Unit 4 (Rates, Equilibria and Further Organic Chemistry) stood out as the most challenging papers, featuring complex multi-step organic syntheses and multi-stage quantitative redox problems.
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.