CHEMISTRY · Common Test for University Admissions (大学入学共通テスト)
CHEMISTRY/11
Chemistry
Chemistry · 2020 · Variant 1
Relative difficulty
Analysis source: National Center for University Entrance Examinations (DNC)
Analysis aligned to the official syllabus and assessment design.
4.0 / 5
100
60 min
Stoichiometry, equilibrium, acid-base/redox calculations and organic structure-property reasoning provide the largest return for preparation.
Cohort performance
Session statistics from official examination reports
Total marks
100
Duration
60 min
Session difficulty
4.0 / 5
Calculator policy
Scientific calculators permitted only where specified in the DNC implementation guidelines; programming functions and CAS are prohibited. En
Key examiner messages
Top priorities from the principal examiner before you revise
化学 covers matter and particles, chemical bonding, states of matter, reactions, equilibrium, acids and bases, oxidation-reduction, inorganic substances, organic compounds and polymers. R7 Common Test chemistry emphasizes quantitative reasoning, experiment interpretation and con…
Chemistry is scheduled as 60 minutes/100 marks for one science subject, or within 130 minutes/200 marks for two sciences.
Amount of substance is the central bridge: particles = moles x Avogadro constant, mass = moles x molar mass, solution moles = concentration x volume.
For titration, neutralization condition is acid valence x acid molarity x acid volume = base valence x base molarity x base volume.
The DNC Problem Evaluation Committee publishes per-subject reports after each January session, rating alignment with the Course of Study (学習指導要領), item difficulty balance, and whether items discriminate without exceeding syllabus scope.
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.
Quantitative calculation
Weight: 34100%Experiment/data interpretation
Weight: 2676%Conceptual particle reasoning
Weight: 2471%Substance identification
Weight: 1647%
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 ratios from coefficients instead of mole ratios. — Convert all given quantities to moles before applying the ba…
Equilibrium: Reversing the sign of concentration change in an ICE table. — Define the reaction direction and write coefficient-scaled cha…
Acid-base: Assuming equal volumes mean neutralization. — Compare moles of H+ and OH- using concentration x volume x valence.
Organic chemistry: Identifying compounds from formula alone without functional-group behavior. — Use reaction tests and structural featur…
Redox: Forgetting that oxidation number can change without visible oxygen transfer. — Calculate oxidation numbers systematically for the …
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
National Center for University Entrance Examinations (DNC)
Grading system
Full science subjects are scored 0–100 raw; universities use deviation values (偏差値)
Scale band
0–100 raw
Scale band
Deviation 50 = mean
Scale band
University cut-off
Deep insights
What top candidates did
Techniques and approaches examiners rewarded in this series
Balance first, calculate second
Every stoichiometry item starts with the balanced equation. Circle the mole ratio, then convert mass, gas volume or concentration into moles.
Use ICE tables for equilibrium
Initial-change-equilibrium tables prevent sign errors in Kc, Kp, solubility and weak-acid/base problems. Keep expressions symbolic until the final substitution.
Separate acid-base ideas
Know strong versus weak, concentration versus amount, pH versus neutralization point and indicator range. These distinctions drive titration questions.
Track electrons in redox
Assign oxidation numbers, identify oxidation and reduction, then balance electrons. Do not infer redox only from oxygen appearing in the formula.
Learn reaction signatures
For inorganic and organic identification, connect observations to ions or functional groups: precipitate color, gas evolution, oxidation, esterification and addition reactions.
Check units and significant ratios
Molar mass, mol/L, gas volume and percent composition are frequent sources of one-step errors. Write units through the whole calculation.
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
Particles, bonding, states and thermochemistry
Official topic weighting
Stoichiometry, acids/bases, redox and equilibrium
Official topic weighting
Inorganic substances and industrial chemistry
Official topic weighting
Organic compounds, polymers and biomolecules
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
Stoichiometry, acids/bases, redox and equilibrium
Organic compounds, polymers and biomolecules
Particles, bonding, states and thermochemistry
Inorganic substances and industrial chemistry
Difficulty trend
How session difficulty has shifted across recent years
Paper comparison
Marks and duration breakdown across papers in this session
Chemistry: for one science subject / for two science subjects Stoichiometry, equilibrium, acid-base, redox, inorganic, organic and polymer 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
Particles, bonding, states and thermochemistry
Official topic weighting
Practise in RevuiStoichiometry, acids/bases, redox and equilibrium
Official topic weighting
Practise in RevuiInorganic substances and industrial chemistry
Official topic weighting
Practise in RevuiOrganic compounds, polymers and biomolecules
Official topic weighting
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
化学 covers matter and particles, chemical bonding, states of matter, reactions, equilibrium, acids and bases, oxidation-reduction, inorganic substances, organic compounds and polymers. R7 Common Test chemistry emphasizes quantitative reasoning, experiment interpretation and con…
- 2Message
Chemistry is scheduled as 60 minutes/100 marks for one science subject, or within 130 minutes/200 marks for two sciences.
- 3Message
Amount of substance is the central bridge: particles = moles x Avogadro constant, mass = moles x molar mass, solution moles = concentration x volume.
- 4Message
For titration, neutralization condition is acid valence x acid molarity x acid volume = base valence x base molarity x base volume.
- 5Message
The DNC Problem Evaluation Committee publishes per-subject reports after each January session, rating alignment with the Course of Study (学習指導要領), item difficulty balance, and whether items discriminate without exceeding syllabus scope.
- 6Pitfall
Stoichiometry: Using mass ratios from coefficients instead of mole ratios. — Convert all given quantities to moles before applying the ba…
- 7Pitfall
Equilibrium: Reversing the sign of concentration change in an ICE table. — Define the reaction direction and write coefficient-scaled cha…
- 8Pitfall
Acid-base: Assuming equal volumes mean neutralization. — Compare moles of H+ and OH- using concentration x volume x valence.
- 9Pitfall
Organic chemistry: Identifying compounds from formula alone without functional-group behavior. — Use reaction tests and structural featur…
- 10Pitfall
Redox: Forgetting that oxidation number can change without visible oxygen transfer. — Calculate oxidation numbers systematically for the …
- 11Strength
Balance first, calculate second: Every stoichiometry item starts with the balanced equation. Circle the mole ratio, then convert mass
- 12Strength
Use ICE tables for equilibrium: Initial-change-equilibrium tables prevent sign errors in Kc, Kp, solubility and weak-acid/base probl
- 13Strength
Separate acid-base ideas: Know strong versus weak, concentration versus amount, pH versus neutralization point and indicator r
Teacher briefing pack
One-page session summary for tutors and classroom review
2020 2020
Chemistry
化学 covers matter and particles, chemical bonding, states of matter, reactions, equilibrium, acids and bases, oxidation-reduction, inorganic substances, organic compounds and polymers. R7 Common Test chemistry emphasizes quantitative reasoning, experiment interpretation and connec
化学 covers matter and particles, chemical bonding, states of matter, reactions, equilibrium, acids and bases, oxidation-reduction, inorganic substances, organic compounds and polymers. R7 Common Test chemistry emphasizes quantitative reasoning, experiment interpretation and con…
Chemistry is scheduled as 60 minutes/100 marks for one science subject, or within 130 minutes/200 marks for two sciences.
Amount of substance is the central bridge: particles = moles x Avogadro constant, mass = moles x molar mass, solution moles = concentration x volume.
Stoichiometry: Using mass ratios from coefficients instead of mole ratios. — Convert all given quantities to moles before applying the ba…
Equilibrium: Reversing the sign of concentration change in an ICE table. — Define the reaction direction and write coefficient-scaled cha…
- Total marks
- 100
- Duration
- 60 min
- Session difficulty
- 4.0 / 5
- Calculator policy
- Scientific calculators permitted only where specified in the DNC implementation guidelines; programming functions and CAS are prohibited. En
Session analysis
化学 covers matter and particles, chemical bonding, states of matter, reactions, equilibrium, acids and bases, oxidation-reduction, inorganic substances, organic compounds and polymers. R7 Common Test chemistry emphasizes quantitative reasoning, experiment interpretation and connecting microscopic particle models to macroscopic observations. National Center for University Entrance Examinations (DNC) emphasises stoichiometry, equilibrium, acid-base/redox calculations and organic structure-property reasoning provide the largest return for preparation.. Priority revision: Particles, bonding, states and thermochemistry, Stoichiometry, acids/bases, redox and equilibrium, Inorganic substances and industrial chemistry, Organic compounds, polymers and biomolecules. Every stoichiometry item starts with the balanced equation. Circle the mole ratio, then convert mass, gas volume or concentration into moles.
Updated 2026-07-03
Paper breakdown
Chemistry: for one science subject / for two science subjects Stoichiometry, equilibrium, acid-base, redox, inorganic, organic and polymer 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.
Stoichiometry, equilibrium, acid-base/redox calculations and organic structure-p
Paper structure
Official paper breakdown for this subject.
Chemistry
100·10·100%
Official syllabus scope
化学 covers matter and particles, chemical bonding, states of matter, reactions, equilibrium, acids and bases, oxidation-reduction, inorganic substances, organic compounds and polymers. R7 Common Test chemistry emphasizes quantitative reasoning, experiment interpretation and connecting microscopic particle models to macroscopic observations.
Difficulty verdict
Rated 4/5 for January sessions. Stoichiometry, equilibrium, acid-base/redox calculations and organic structure-property reasoning provide the largest return for preparation.
What examiners measure
1. Use mole relationships, balanced equations and concentration calculations accurately. 2. Explain chemical phenomena using particle, bonding and energy models. 3. Interpret experiments, graphs, titration curves and equilibrium data. 4. Apply acid-base, redox and equilibrium concepts to unfamiliar contexts. 5. Identify inorganic and organic substances from reactions, structures and properties.
Where the marks are
Highest-weight syllabus areas: Particles, bonding, states and thermochemistry; Stoichiometry, acids/bases, redox and equilibrium; Inorganic substances and industrial chemistry; Organic compounds, polymers and biomolecules.
Examiner notes & key calculations
- Chemistry is scheduled as 60 minutes/100 marks for one science subject, or within 130 minutes/200 marks for two sciences.
- Amount of substance is the central bridge: particles = moles x Avogadro constant, mass = moles x molar mass, solution moles = concentration x volume.
- For titration, neutralization condition is acid valence x acid molarity x acid volume = base valence x base molarity x base volume.
- Equilibrium constants omit pure solids and liquids; include only gases and solutes as appropriate.
- Le Chatelier questions require specifying the stress and the direction that reduces that stress, not just saying equilibrium shifts.
- Organic structure questions often use degree of unsaturation, functional group reactions and isomer count together.
- Experiment interpretation is official high priority: identify the measurement, control variable and chemical quantity inferred from the graph.
- Paper 1: Chemistry · 100 marks · 60 min for one science subject / 130 min for two science subjects · Stoichiometry, equilibrium, acid-base, redox, inorganic, organic and polymer chemistry.
Exam tips
Paper format
- Duration
- 60 min for one science subject / 130 min for two science subjects
- Total marks
- 100
- Weighting
- 100%
- Question types
- Stoichiometry, equilibrium, acid-base, redox, inorganic, organic and polymer chemistry
- Every stoichiometry item starts with the balanced equation. Circle the mole ratio, then convert mass, gas volume or concentration into moles.
- Initial-change-equilibrium tables prevent sign errors in Kc, Kp, solubility and weak-acid/base problems. Keep expressions symbolic until the final substitution.
- Know strong versus weak, concentration versus amount, pH versus neutralization point and indicator range. These distinctions drive titration questions.
Common mistakes
Stoichiometry
Using mass ratios from coefficients instead of mole ratios.
How to avoid: Convert all given quantities to moles before applying the balanced-equation ratio.
Equilibrium
Reversing the sign of concentration change in an ICE table.
How to avoid: Define the reaction direction and write coefficient-scaled changes for every species.
Acid-base
Assuming equal volumes mean neutralization.
How to avoid: Compare moles of H+ and OH- using concentration x volume x valence.
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.