A-LEVEL-CHEMISTRY · TCAS Exam Preparation (เตรียมสอบ TCAS)
A-LEVEL-CHEMISTRY/11
A-Level Chemistry
A-Level Chemistry · tcas-round 2022 · Variant 1
Relative difficulty
Analysis source: Council of University Presidents of Thailand (CUPT) / NIETS
Analysis aligned to the official syllabus and assessment design.
4.0 / 5
100
90 min
Mole-based calculation, structure-property reasoning, and reaction prediction across acid-base, redox, and equilibrium contexts.
Cohort performance
Session statistics from official examination reports
Total marks
100
Duration
90 min
Session difficulty
4.0 / 5
Calculator policy
TGAT papers: no calculator unless stated. TPAT and A-Level papers: basic calculators allowed where specified in the official blueprint.
Key examiner messages
Top priorities from the principal examiner before you revise
A-Level Chemistry assesses upper-secondary chemistry for TCAS in a 90-minute paper. The official blueprint weights substances/properties, reactions, and practical chemistry.
Official blueprint: substances/properties 15-17 items, reactions 15-17 items, practical chemistry 2-4 items.
A-Level score conversion uses Ti = 50 + 5.21299 * (raw - mean) / SD.
The paper is nearly balanced between properties and reactions, so both conceptual and calculation fluency are required.
CUPT/NIETS blueprints at mytcas.com define item counts, timing, and competency weights. Blueprints are advisory — live papers may vary slightly in difficulty distribution.
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
Cognitive skills emphasised in official test design.
Chemical calculation
Weight: 30100%Conceptual structure-property reasoning
Weight: 2583%Reaction analysis
Weight: 2583%Experimental interpretation
Weight: 1033%Organic and materials application
Weight: 1033%
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
Stoichiometry: Using mass ratio instead of mole ratio from the balanced equation. — Circle coefficients and convert all given quantities …
Equilibrium: Adding instead of subtracting the change term in an ICE table. — Link sign to reaction direction before writing equilibrium …
Acid-base: Confusing strong with concentrated and weak with dilute. — Separate degree of ionisation from amount per volume.
Redox: Losing electrons when balancing half-reactions. — Check total charge and atoms on both sides.
Practical: Choosing an apparatus with unsuitable precision. — Match measuring device to required accuracy and volume range.
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
Official body
Office of the Higher Education Commission (OCSC) / NIETS
Grading system
CUPT A-Level T-score: Ti = 50 + 5.21299 × (raw − mean) / SD; national mean Ti = 50
Scale band
Raw 0–100
Scale band
T-score 40
Scale band
T-score 50
Scale band
T-score 60
Deep insights
What top candidates did
Techniques and approaches examiners rewarded in this series
1. Write the balanced equation first
Stoichiometry, gas, titration, redox, and equilibrium items all depend on mole ratios. Do not calculate before balancing.
2. Build a mole map
Convert mass, volume, concentration, or particles to moles, use the coefficient ratio, then convert to the requested quantity.
3. Link structure to property
For bonding and materials, explain melting point, solubility, conductivity, volatility, and reactivity from particle-level structure.
4. Use equilibrium tables
ICE tables prevent sign and concentration errors. Write initial, change, and equilibrium rows before substituting into K.
5. Treat practical items as evidence
Identify variable, control, apparatus, measurement, uncertainty, safety, and conclusion from the experiment description.
6. Drill redox systematically
Assign oxidation numbers, identify oxidation and reduction, balance electrons, then combine half-equations.
Command word playbook
How to match each command word to the expected response style
No data available in official reports
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
Substances and properties
Official topic weighting
Chemical reactions
Official topic weighting
Practical and experimental chemistry
Official topic weighting
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
Substances and properties
Chemical reactions
Practical and experimental chemistry
Difficulty trend
How session difficulty has shifted across recent years
Paper comparison
Marks and duration breakdown across papers in this session
A-Level Chemistry: Properties, reactions, and practical chemistry
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
Substances and properties
Official topic weighting
Practise in RevuiChemical reactions
Official topic weighting
Practise in RevuiPractical and experimental chemistry
Official topic weighting
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
A-Level Chemistry assesses upper-secondary chemistry for TCAS in a 90-minute paper. The official blueprint weights substances/properties, reactions, and practical chemistry.
- 2Message
Official blueprint: substances/properties 15-17 items, reactions 15-17 items, practical chemistry 2-4 items.
- 3Message
A-Level score conversion uses Ti = 50 + 5.21299 * (raw - mean) / SD.
- 4Message
The paper is nearly balanced between properties and reactions, so both conceptual and calculation fluency are required.
- 5Message
CUPT/NIETS blueprints at mytcas.com define item counts, timing, and competency weights. Blueprints are advisory — live papers may vary slightly in difficulty distribution.
- 6Pitfall
Stoichiometry: Using mass ratio instead of mole ratio from the balanced equation. — Circle coefficients and convert all given quantities …
- 7Pitfall
Equilibrium: Adding instead of subtracting the change term in an ICE table. — Link sign to reaction direction before writing equilibrium …
- 8Pitfall
Acid-base: Confusing strong with concentrated and weak with dilute. — Separate degree of ionisation from amount per volume.
- 9Pitfall
Redox: Losing electrons when balancing half-reactions. — Check total charge and atoms on both sides.
- 10Pitfall
Practical: Choosing an apparatus with unsuitable precision. — Match measuring device to required accuracy and volume range.
- 11Strength
1. Write the balanced equation first: Stoichiometry, gas, titration, redox, and equilibrium items all depend on mole ratios. Do not calcul
- 12Strength
2. Build a mole map: Convert mass, volume, concentration, or particles to moles, use the coefficient ratio, then convert
- 13Strength
3. Link structure to property: For bonding and materials, explain melting point, solubility, conductivity, volatility, and reactivi
Teacher briefing pack
One-page session summary for tutors and classroom review
tcas-round 2022 2022
A-Level Chemistry
A-Level Chemistry assesses upper-secondary chemistry for TCAS in a 90-minute paper. The official blueprint weights substances/properties, reactions, and practical chemistry. Office of the Higher Education Commission (OCSC) / NIETS emphasises mole-based calculation, structure-prop
A-Level Chemistry assesses upper-secondary chemistry for TCAS in a 90-minute paper. The official blueprint weights substances/properties, reactions, and practical chemistry.
Official blueprint: substances/properties 15-17 items, reactions 15-17 items, practical chemistry 2-4 items.
A-Level score conversion uses Ti = 50 + 5.21299 * (raw - mean) / SD.
Stoichiometry: Using mass ratio instead of mole ratio from the balanced equation. — Circle coefficients and convert all given quantities …
Equilibrium: Adding instead of subtracting the change term in an ICE table. — Link sign to reaction direction before writing equilibrium …
- Total marks
- 100
- Duration
- 90 min
- Session difficulty
- 4.0 / 5
- Calculator policy
- TGAT papers: no calculator unless stated. TPAT and A-Level papers: basic calculators allowed where specified in the official blueprint.
Session analysis
A-Level Chemistry assesses upper-secondary chemistry for TCAS in a 90-minute paper. The official blueprint weights substances/properties, reactions, and practical chemistry. Office of the Higher Education Commission (OCSC) / NIETS emphasises mole-based calculation, structure-property reasoning, and reaction prediction across acid-base, redox, and equilibrium contexts.. Priority revision: Substances and properties, Chemical reactions, Practical and experimental chemistry. Stoichiometry, gas, titration, redox, and equilibrium items all depend on mole ratios. Do not calculate before balancing.
Updated 2026-07-03
Paper breakdown
A-Level Chemistry: Properties, reactions, and practical chemistry
Top chapters
Exam structure insights
Marks by syllabus topic
Revision priority from official test-design weighting.
Mark accessibility
Estimated difficulty spread based on official design.
Mole-based calculation, structure-property reasoning, and reaction prediction ac
Paper structure
Official paper breakdown for this subject.
A-Level Chemistry
100·10·100%
Official syllabus scope
A-Level Chemistry assesses upper-secondary chemistry for TCAS in a 90-minute paper. The official blueprint weights substances/properties, reactions, and practical chemistry.
Difficulty verdict
Rated 4/5 for March–April sessions. Mole-based calculation, structure-property reasoning, and reaction prediction across acid-base, redox, and equilibrium contexts.
What examiners measure
1. Apply atomic, bonding, structure, and property concepts to chemical substances. 2. Use stoichiometry, equilibrium, acid-base, redox, kinetics, and thermochemistry in reaction problems. 3. Interpret experimental procedures, observations, variables, safety, and data. 4. Connect chemical principles to materials, environment, industry, and everyday applications. 5. Calculate accurately with moles, concentration, gas volume, and reaction relationships.
Where the marks are
Highest-weight syllabus areas: Substances and properties; Chemical reactions; Practical and experimental chemistry.
Examiner notes & key calculations
- Official blueprint: substances/properties 15-17 items, reactions 15-17 items, practical chemistry 2-4 items.
- A-Level score conversion uses Ti = 50 + 5.21299 * (raw - mean) / SD.
- The paper is nearly balanced between properties and reactions, so both conceptual and calculation fluency are required.
- Practical chemistry is a smaller item range but often tests details candidates overlook in theory-only revision.
- Mole ratios from balanced equations underpin many high-value distractors.
- Structure-property explanations should move from particle model to observable property.
- No negative marking means estimation and unit checks should be used when arithmetic is uncertain.
- Paper 1: A-Level Chemistry · 100 marks · 90 min · Properties, reactions, and practical chemistry.
Exam tips
Paper format
- Duration
- 90 min
- Total marks
- 100
- Weighting
- 100%
- Question types
- Properties, reactions, and practical chemistry
- Stoichiometry, gas, titration, redox, and equilibrium items all depend on mole ratios. Do not calculate before balancing.
- Convert mass, volume, concentration, or particles to moles, use the coefficient ratio, then convert to the requested quantity.
- For bonding and materials, explain melting point, solubility, conductivity, volatility, and reactivity from particle-level structure.
Common mistakes
Stoichiometry
Using mass ratio instead of mole ratio from the balanced equation.
How to avoid: Circle coefficients and convert all given quantities to moles.
Equilibrium
Adding instead of subtracting the change term in an ICE table.
How to avoid: Link sign to reaction direction before writing equilibrium concentrations.
Acid-base
Confusing strong with concentrated and weak with dilute.
How to avoid: Separate degree of ionisation from amount per volume.
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.