How Are the IB Chemistry Exam Papers Structured?

IB Chemistry has three exam papers plus the IA. Paper 1 is multiple-choice covering the whole syllabus, Paper 2 is extended-response questions, and Paper 3 tests data-based and practical skills. All three now allow calculators, following the syllabus first examined in 2025.

Paper 1 is straight multiple-choice testing recall and quick application across all topics. Paper 2 has short-answer and extended-response questions that need full working and correct units. Paper 3 gives you unfamiliar data — a graph, table or experimental scenario — and asks you to analyse it using syllabus knowledge.

SL and HL students sit the same three papers, but HL papers run longer and go deeper, especially on topics 12–21 (the HL-only content). Paper 3 for HL includes more demanding data-analysis questions and a wider spread of practical scenarios than the SL version.

At SL: Paper 1 is 45 minutes, Paper 2 is 1 hour 15, and Paper 3 is 45 minutes — about 2 hours 45 total. At HL: Paper 1 is 1 hour 15, Paper 2 is 2 hours 15, and Paper 3 is 1 hour 15 — around 4 hours 45 total.

"State", "Calculate", "Determine", "Explain" and "Deduce" dominate Paper 2. Each demands a different depth of answer — "state" wants one fact, no working; "explain" needs a reasoned mechanism or cause-and-effect chain, usually worth two or more marks.

Paper 3 feels harder than it is because it looks unfamiliar — you're given data you haven't seen before rather than recalling facts. Students who practise past-paper data questions regularly usually find it more predictable than Paper 2, since the skills tested (graphing, error analysis, uncertainty) repeat every year.

Grade boundaries shift each session, but scoring above roughly 65–70% on Paper 1 typically keeps you in range for a 6 or 7 overall, assuming similar performance across the other papers. Boundaries are set after each exam session, not fixed in advance, so treat any number as a rough guide, not a target.

In my experience marking mocks, Paper 2 costs students the most marks — not through lack of knowledge, but through missing units, rounding to the wrong significant figures, or skipping a required step in a multi-part calculation that examiners award marks for individually.

Work through past Paper 2 questions topic by topic, then time yourself on a full paper under exam conditions at least twice before the real thing. Focus on the calculation-heavy topics — equilibrium, kinetics, and energetics — since these carry the most multi-mark questions and are where marks are lost fastest.

Paper 3 draws from across the whole syllabus rather than a fixed section, since the 2025 Chemistry guide removed the separate options entirely. Expect one data-based question plus several shorter questions linking experimental technique to core topics like enthalpy, rates and structure.

IB Chemistry HL covers a similar depth to A-Level Chemistry but spreads assessment across three exam papers plus a mandatory Internal Assessment, which A-Level doesn't require. Many teachers find the IB's emphasis on data analysis and practical evaluation in Paper 3 adds a layer A-Level students don't face in the same way.

Costs vary widely — a school textbook and past papers might cost very little if your school provides them, while private revision guides, worksheets and mock papers typically range from free (past papers via your school) to a modest subscription for structured resources like question banks and topical worksheets.