TWENTY-FIRST-CENTURY-SCIENCE-CHEMISTRY-B-J258 · Cambridge OCR GCSE (9–1)
TWENTY-FIRST-CENTURY-SCIENCE-CHEMISTRY-B-J258/41
Depth in Chemistry (Higher Tier)
Twenty First Century Science Chemistry B · June 2024 · Variant 1
Relative difficulty
Analysis source: OCR
Analysis aligned to the official syllabus and assessment design.
3.2 / 5
180
210 min
Bonding, Structure, and Material Properties
Cohort performance
Session statistics from official examination reports
Total marks
180
Duration
210 min
Session difficulty
3.2 / 5
Key examiner messages
Top priorities from the principal examiner before you revise
Marks were heavily concentrated in the Material Choices and Chemical Analysis modules.
Bonding and structure emerged as the single most critical theme, commanding 20 marks across both papers.
Students who mastered the properties of giant covalent structures (diamond/graphite) versus simple covalent molecules (water) were richly rewarded.
Environmental chemistry and atmospheric changes also accounted for a combined 16 marks, reinforcing OCR's consistent emphasis on global warming, emissions calculations, and sustainability.
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: 6100%Practical & Experimental
Weight: 583%Extended
Weight: 350%Written Interpretation
Weight: 233%
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 9
Approx. 71% of maximum mark
Level 8
Approx. 63% of maximum mark
Level 7
Approx. 56% of maximum mark
Level 6
Approx. 45% of maximum mark
Level 5
Approx. 35% of maximum mark
Level 4
Approx. 25% of maximum mark
Level 3
Approx. 20% of maximum mark
Deep insights
What top candidates did
Techniques and approaches examiners rewarded in this series
Analysis of Key Core Themes and Mark Allocation
Marks were heavily concentrated in the Material Choices and Chemical Analysis modules. Bonding and structure emerged as the single most critical theme, commanding 20 marks across both papers. Students who mastered the properties of giant covalent structures (diamond/graphite) versus simple covalent molecules (water) were richly rewarded. Environmental chemistry and atmospheric changes also account
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.
State features in sequence or list observable properties — do not explain causes unless asked.
Weigh arguments for and against with evidence; end with a supported judgement.
Match the expected response style for “Complete” questions.
Apply knowledge to an unfamiliar context; concise, practical points score best.
Match the expected response style for “State” questions.
Time traps
Sections where candidates spent disproportionate time relative to marks
Min per mark: 1.2
Min per mark: 1.2
Syllabus traceability
Topics linked to questions and mark weighting in this session
How do bonding and structure affect properties of materials? (Material choices)
20 marks this session
How do chemists control the rate of reactions? (Making useful chemicals)
16 marks this session
How has the Earth’s atmosphere changed over time, and why? (Air and water)
16 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
How do bonding and structure affect properties of materials?
How do chemists control the rate of reactions?
Why is crude oil important as a source of new materials?
How do bonding and structure affect properties of materials? (Material choices)
How do chemists control the rate of reactions? (Making useful chemicals)
How has the Earth’s atmosphere changed over time, and why? (Air and water)
How are the amounts of chemicals in solution measured? (Chemical analysis)
What is the evidence for climate change, why is it occurring? (Air and water)
Paper comparison
Marks and duration breakdown across papers in this session
J258/03 Breadth in Chemistry (Higher Tier): J258/04 Depth in Chemistry (Higher Tier):
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
How do bonding and structure affect properties of materials? (Material choices)
20 marks this session
Practise in RevuiHow do chemists control the rate of reactions? (Making useful chemicals)
16 marks this session
Practise in RevuiHow has the Earth’s atmosphere changed over time, and why? (Air and water)
16 marks this session
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
Marks were heavily concentrated in the Material Choices and Chemical Analysis modules.
- 2Message
Bonding and structure emerged as the single most critical theme, commanding 20 marks across both papers.
- 3Message
Students who mastered the properties of giant covalent structures (diamond/graphite) versus simple covalent molecules (water) were richly rewarded.
- 4Message
Environmental chemistry and atmospheric changes also accounted for a combined 16 marks, reinforcing OCR's consistent emphasis on global warming, emissions calculations, and sustainability.
- 5Strength
Analysis of Key Core Themes and Mark Allocation: Marks were heavily concentrated in the Material Choices and Chemical Analysis modules. Bonding and s
Teacher briefing pack
One-page session summary for tutors and classroom review
June 2024 2024
Twenty First Century Science Chemistry B
Marks were heavily concentrated in the Material Choices and Chemical Analysis modules. Bonding and structure emerged as the single most critical theme, commanding 20 marks across both papers. Students who mastered the properties of giant covalent structures (diamond/graphite) ver
Marks were heavily concentrated in the Material Choices and Chemical Analysis modules.
Bonding and structure emerged as the single most critical theme, commanding 20 marks across both papers.
Students who mastered the properties of giant covalent structures (diamond/graphite) versus simple covalent molecules (water) were richly rewarded.
- Total marks
- 180
- Duration
- 210 min
- Session difficulty
- 3.2 / 5
Session analysis
Marks were heavily concentrated in the Material Choices and Chemical Analysis modules. Bonding and structure emerged as the single most critical theme, commanding 20 marks across both papers. Students who mastered the properties of giant covalent structures (diamond/graphite) versus simple covalent molecules (water) were richly rewarded. Environmental chemistry and atmospheric changes also accounted for a combined 16 marks, reinforcing OCR's consistent emphasis on global warming, emissions calculations, and sustainability. Quantitative skills, including atom economy, percentage yield, and gas volume conversions, represented over 45% of the total available marks, highlighting the non-negotiable nature of mathematical practice.
Updated Jun 14, 2026
Paper breakdown
J258/03 Breadth in Chemistry (Higher Tier): J258/04 Depth in Chemistry (Higher Tier):
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.
Calculations
82·15·46%
Short Answer / Structured
52·32·29%
Level of Response
(Extended Writing)
24·4·13%
Multiple Choice / Tick Box
22·14·12%
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.
J258/03 Breadth in
0.86 m/minJ258/04 Depth in Ch
0.86 m/minTotal marks
180
Total time
210 min
Avg pace
0.86
Next-year prediction
Topics worth watching next year, with the reason shown directly below each bar.
How are the amounts of chemicals in solution measured?
92%92%
What are electrolytes and what happens during electrolysis?
88%88%
Analysis of Key Core Themes and Mark Allocation
Marks were heavily concentrated in the Material Choices and Chemical Analysis modules. Bonding and structure emerged as the single most critical theme, commanding 20 marks across both papers. Students who mastered the properties of giant covalent structures (diamond/graphite) versus simple covalent molecules (water) were richly rewarded. Environmental chemistry and atmospheric changes also accounted for a combined 16 marks, reinforcing OCR's consistent emphasis on global warming, emissions calculations, and sustainability. Quantitative skills, including atom economy, percentage yield, and gas volume conversions, represented over 45% of the total available marks, highlighting the non-negotiable nature of mathematical practice.
Exam tips
Paper format
- Duration
- 1h 45min
- Total marks
- 90
- Weighting
- 50%
- Question types
- Multiple Choice / Tick Box, Short Answer / Structured, Calculations, Level of Response (Extended Writing)
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.