The Most-Tested Topics in IB Chemistry SL
Every IB Chemistry SL past-paper question, mapped to the current syllabus and ranked by how often each topic is tested (2016–2025).
All topics (SL) ()
42 papers analysed · top 15 of 20 topics
| # | Topic | % of all SL questions | Questions | Avg marks |
|---|---|---|---|---|
| 1 | Introduction to organic chemistry | 24.1% | 166 | 2.9 |
| 2 | Reacting masses and volumes | 15.2% | 105 | 4 |
| 3 | The mole concept | 13.6% | 94 | 3.3 |
| 4 | Covalent bonding | 13.3% | 92 | 3.8 |
| 5 | Enthalpy of reaction | 11.4% | 79 | 2.1 |
| 6 | Periodic trends in atomic properties | 11% | 76 | 2.8 |
| 7 | Electron transfer reactions (redox and electrochemistry) | 10.7% | 74 | 2.1 |
| 8 | Proton transfer reactions (acids and bases) | 10.4% | 72 | 2.9 |
| 9 | Collision theory and reaction rates | 10.3% | 71 | 4.3 |
| 10 | Reactivity 2: Energetics and Kinetics | 9.3% | 64 | 4.6 |
| 11 | Atomic number, mass number and isotopes | 8.3% | 57 | 2.3 |
| 12 | Structure 2: Electron Configuration | 7.2% | 50 | 3.2 |
| 13 | Particulate nature of matter | 6.4% | 44 | 0.5 |
| 14 | Hess's law | 4.9% | 34 | 1.5 |
| 15 | Bonding continuum and materials (polymers) | 4.9% | 34 | 4.3 |
How this was measured
Based on OwlsPrep's database of IB Chemistry SL past papers (2016–2025), 690 questions each tagged to its syllabus topic and mapped to the current IB syllabus via our topic crosswalk. “% of all SL questions” = the share of all tagged IB Chemistry SL questions that test the topic. Topics no longer in the current syllabus are excluded; because one question can test several topics, shares do not sum to 100%. Figures are aggregate statistics from question metadata — no exam questions or mark schemes are reproduced.
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