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IB Chemistry Past Paper Drilling (SL and HL): Structure and Reactivity
TUTORZONE EXAM DRILL GUIDE · IB CHEMISTRY (SL/HL)
IB Chemistry (first assessment 2025) is 80% external: Paper 1 (1A multiple-choice plus 1B data-based and experimental questions) is 36%, Paper 2 (short-answer and extended-response) 44%, and the scientific investigation report takes the remaining 20%. The syllabus is organised into Structure and Reactivity.
How many papers does IB Chemistry have and what are they worth?
Direct answer: under the course first assessed in 2025, external assessment is 80%: Paper 1 (1A multiple-choice plus 1B data-based and experimental questions) 36% and Paper 2 (short-answer and extended-response) 44%, with the internal scientific investigation at 20%. Paper 1 runs 1.5 h at SL and 2 h at HL; Paper 2 1.5 h at SL and 2.5 h at HL.
Assessment at a glance (2027)
| Component | Content | Weighting | Duration |
|---|---|---|---|
| Paper 1 · 1A multiple-choice | Combined with 1B into 36% of the subject; 1.5 h at SL and 2 h at HL | 36%（與 1B 合併） | 1.5 h SL / 2 h HL |
| Paper 1 · 1B data-based and experimental | Part of the same 36%; the brief states 1B covers data-based questions and questions on experimental work | 36%（與 1A 合併） | Inside the Paper 1 time |
| Paper 2 · short-answer and extended-response | 44% of the subject, the heaviest component; 1.5 h SL and 2.5 h HL | 44% | 1.5 h SL / 2.5 h HL |
| Scientific investigation · internal | 20% of the subject, 10 hours recommended, report of up to 3,000 words | 20% | 10 hours |
Chemistry’s marks sit mainly in Paper 2’s 44%. Losses are habitual and twofold: unbalanced equations, and explanations that describe the phenomenon without a particle-level cause. Both respond to a fixed checklist within weeks.
What each paper is actually testing
| Paper | Drill focus | How marks are lost |
|---|---|---|
| Paper 1 · 1A multiple-choice | Drill confusable pairs: ionic versus covalent, enthalpy versus entropy, acids versus titration curves | Answering from impression instead of returning to the periodic table or structure |
| Paper 1 · 1B data-based and experimental | For experimental items, name the apparatus choice, the error source and the improvement | Describing the procedure without the error and the improvement |
| Paper 2 · short-answer and extended-response | Balance equations with states and conditions; explanations must reach the particle or bond level | Unbalanced equations and phenomenon-only explanations |
| Scientific investigation · internal | Choose a question with a measurable dependent variable: titration, colorimetry, rate measurement | Qualitative observation only, with no analysable data |
How is the IB Chemistry syllabus organised?
Direct answer: the brief groups the course under Structure (models of the particulate nature of matter, bonding and structure, classification of matter) and Reactivity (what drives reactions, how much and how fast, the mechanisms of chemical change). Organise drilling along those two lines rather than in textbook chapter order.
Drill order: by topic, then by year, then the mark scheme
| Step | What you do | Why |
|---|---|---|
| 1. By topic | Work through each topic, starting with the paper that allows least help (no calculator / closed book) | Exposes what is genuinely not understood |
| 2. By year | Whole papers to time, one or two a week | Trains pace, stamina and question selection |
| 3. Mark scheme | Go through the marking scheme question by question and log the scoring steps you missed | Most lost marks are written wrong, not thought wrong |
What do experimental questions require?
Direct answer: the brief states 1B covers data-based questions and questions on experimental work. Answers should name three things: why that apparatus or method, the main error sources (indicator end point, heat loss) and how to improve (finer measuring tools, insulation). Describing the steps alone earns little.
A 12-week drilling timetable
| Week | Phase | What to do |
|---|---|---|
| Weeks 1-3 | By topic: foundation | Topic by topic, starting with the easiest marks, building habits and recall |
| Weeks 4-6 | By topic: core | 8-10 years of the same topic back to back, errors classified by topic |
| Weeks 7-8 | By topic: advanced and electives | Elective and higher-order topics, now under time pressure |
| Weeks 9-10 | By year: timed papers | One full paper a week, timed, no reference materials |
| Week 11 | Mark scheme work | Question by question against the marking scheme; list the scoring steps you omitted |
| Week 12 | Plug holes and simulate | Only the recurring errors from your log, then one full exam simulation |
Subject-specific weighting for this timetable: One timed Paper 1 (1A and 1B) plus a Paper 2 topic block weekly, with the investigation advancing monthly and written up immediately.
Use it properly: this is not a checklist to finish. Every week must keep time for redoing errors, or from week 9 you will be repeating the same batch.
Pacing
| Paper | Time | Suggested split |
|---|---|---|
| Paper 1 · 1A multiple-choice | SL 1.5 小時／HL 2 小時 | About 1 min per 1A item |
| Paper 1 · 1B data-based and experimental | 包含在卷一時間內 | About 10 min per question |
| Paper 2 · short-answer and extended-response | SL 1.5 小時／HL 2.5 小時 | About 1.2 min per mark |
| Scientific investigation · internal | 10 小時 | One stage every two weeks |
How should practice be split between the papers?
Direct answer: Paper 2 is 44% and Paper 1 36%, but Paper 1 tests two distinct skills in 1A and 1B. Split practice evenly: one timed Paper 1 a week (1A and 1B together) plus a topic block of Paper 2, with a separate 1B session weekly.
The drilling mistakes that cost the most marks
| Mistake | What it looks like | What actually happens | Instead |
|---|---|---|---|
| Unbalanced equations | Reactants and products only | Balance, states and conditions are marked separately | Check atoms, charge, states and conditions every time |
| Phenomenon-only answers | “It reacts faster” with no cause | No particle-level mechanism, no marks | Phenomenon, mechanism, consequence |
| Skipping 1B | Multiple-choice practice only | 1B is a large share of Paper 1 with different skills | One 1B session a week on data and uncertainty |
The error log and the mark scheme
File by the two strands, Structure and Reactivity, tagging each entry: equation, explanation, calculation or data.
How many years should you drill?
The current course was first assessed in 2025 with Paper 1 split into 1A and 1B; old papers serve as topic and experimental practice.
How many years of past papers should you drill?
Direct answer: no official figure, but note the structure has changed: the course was first assessed in 2025 and Paper 1 now splits into 1A (multiple-choice) and 1B (data and experimental). Old papers are useful for topics and experiments, but they cannot predict the current paper’s structure.
Frequently asked questions
Does Paper 2 cover everything?
The brief describes Paper 2 as short-answer and extended-response questions on the course content; the exact spread follows the official papers and guide.
Must the investigation be an experiment?
The brief describes it as an open-ended task in which students gather and analyse data to answer their own research question.
Must organic reactions be memorised?
Understanding matters more: classify reactions under proton transfer, electron transfer and electron sharing rather than memorising lists.
Official references
| Resource | What to use it for |
|---|---|
| IBO Chemistry subject brief (first assessment 2025) | Confirm Paper 1 36%, Paper 2 44%, the 20% investigation and paper times |
| https://www.tutorzone.com.hk/ib-chemistry-hl | IB Chemistry course guide |
| https://www.tutorzone.com.hk/en-ib-math-aa-past-paper-drill-guide/ | IB Maths AA drilling guide |
Related: IB practice area · IB Physics guide · IB Economics guide
Next step: find a tutor / register as a tutor
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