How this analysis was built — please read
New IB Chemistry syllabus first sat in May 2025. We have 1 real sitting (May 2025) + IBO Specimen papers (2023). To strengthen predictions, we mapped 6 years of old syllabus Paper 1 & Paper 2 data (2019–2024) onto the new 4 themes — core chemistry content is largely preserved. Old Topics 1–11 (Structure / Reactivity) map cleanly onto new Structure and Reactivity sections. Old Paper 3 data excluded (tested options which no longer exist). Source labelled on each row: 🟢 New syllabus · 🟡 Mapped old syllabus.
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Paper 1A — Multiple Choice Questions
⚗️ Chemistry MCQ insight: Chemistry MCQ tests knowledge of structure, bonding, reactions and calculations. In the old syllabus, Topic 1 (Stoichiometry), Topic 4 (Bonding) and Topic 8 (Acids/Bases) dominated. In the new syllabus, Structure 1 (Atomic/Particulate matter) and Reactivity 2 (Kinetics/Equilibrium) are expected to carry the most MCQ weight. Stoichiometry calculations appear in almost every paper.
Paper 1A MCQ frequency — Structure & Reactivity topics (SL & HL)
| IB CHEMISTRY — PAPER 1A MCQ TOPIC FREQUENCY | May 2025 + Mapped Old Syllabus 2019–2024 | SL & HL | ||||||||||
| Free preview: Structure 1 (Atomic model & bonding) · Further topics locked below · 🟢 = new · 🟡 = mapped old · HL rows greyed in SL view | ||||||||||
| Ref | Theme | Topic / Subtopic | M20 | M21 | M22 | M23 | M24 | M25★ | HL only? | May 2026 |
|---|---|---|---|---|---|---|---|---|---|---|
| THEME A: UNITY & DIVERSITY — cells, classification, viruses, biodiversity (free preview) | ||||||||||
| A.1 | Unity/Div | Cell structure — prokaryotic vs eukaryotic, organelles, ultrastructure, scale & magnification 🟡 | ✔ | ✔ | ✔ | ✔ | ✔ | ✔★ | SL&HL | ⭐⭐⭐⭐⭐ CERTAIN |
| A.2 | Unity/Div | Classification & diversity — binomial nomenclature, phylogenetic trees, kingdoms, domains 🟡 | ✔ | — | ✔ | ✔ | ✔ | ✔★ | SL&HL | ⭐⭐⭐⭐ |
| A.3 | Unity/Div | Viruses — structure, lytic & lysogenic cycles, HIV, COVID, virus-host interactions 🟢 | — | — | — | — | — | ✔★ | SL&HL | ⭐⭐⭐⭐ NEW |
| A.4 | Unity/Div | Conservation of biodiversity — species richness, ecosystem services, threats, conservation strategies 🟡 | ✔ | ✔ | — | ✔ | — | ✔★ | SL&HL | ⭐⭐⭐⭐ |
| A.HL | Unity/Div | Cladistics & gene pools — cladograms, shared derived characteristics, species concepts, speciation HL 🟢 | — | — | — | — | — | ✔★ | HL | ⭐⭐⭐⭐ HL NEW |
★ = confirmed appeared May 2025 · 🟢 new syllabus · 🟡 mapped old syllabus | HL-only rows greyed in SL view
| Ref | Theme | Topic / Subtopic | M20 | M21 | M22 | M23 | M24 | M25★ | HL only? | May 2026 |
|---|---|---|---|---|---|---|---|---|---|---|
| STRUCTURE 2: MODELS OF BONDING & STRUCTURE — covalent, metallic, giant ionic | ||||||||||
| S2.1 | Bonding | Ionic structures — lattice energy, properties of ionic compounds, Born-Haber cycle (HL) | ✔ | ✔ | ✔ | ✔ | ✔ | ✔★ | SL&HL | ⭐⭐⭐⭐⭐ |
| S2.2 | Bonding | Covalent structures — allotropes of carbon, giant covalent (SiO2, diamond, graphite), properties | ✔ | ✔ | — | ✔ | ✔ | ✔★ | SL&HL | ⭐⭐⭐⭐ |
| S2.3 | Bonding | Metallic structures — electron sea model, properties, alloys, conductivity | ✔ | — | ✔ | — | ✔ | ✔★ | SL&HL | ⭐⭐⭐ |
| S2.HL | Bonding | Transition metals — d-block, variable oxidation states, complex ions, colour, catalytic properties HL | — | — | — | — | — | ✔★ | HL | ⭐⭐⭐⭐ HL |
| STRUCTURE 3: CLASSIFICATION OF MATTER — organic functional groups, polymers | ||||||||||
| S3.1 | Organic | Functional groups — homologous series, alkanes/alkenes/alkynes/alcohols/aldehydes/ketones/carboxylic acids naming | ✔ | ✔ | ✔ | ✔ | ✔ | ✔★ | SL&HL | ⭐⭐⭐⭐⭐ CERTAIN |
| S3.2 | Organic | Polymers — addition polymerisation, condensation polymers, nylon, polyester, properties | ✔ | — | ✔ | ✔ | — | ✔★ | SL&HL | ⭐⭐⭐⭐ |
| REACTIVITY 1: WHAT DRIVES REACTIONS — energy, entropy, Gibbs energy | ||||||||||
| R1.1 | Reactivity | Measuring energy changes — enthalpy, calorimetry, Hess’s law, bond enthalpies, standard enthalpy | ✔ | ✔ | ✔ | ✔ | ✔ | ✔★★ | SL&HL | ⭐⭐⭐⭐⭐ CERTAIN |
| R1.2 | Reactivity | Energy diagrams — activation energy, reaction profiles, Maxwell-Boltzmann distribution, catalysts | ✔ | ✔ | ✔ | ✔ | ✔ | ✔★ | SL&HL | ⭐⭐⭐⭐⭐ |
| R1.HL | Reactivity | Entropy & Gibbs energy — ΔS, ΔG = ΔH – TΔS, spontaneity, standard Gibbs energy of formation HL | — | — | — | — | — | ✔★★ | HL | ⭐⭐⭐⭐⭐ HL CERTAIN |
| REACTIVITY 2: HOW FAST & HOW FAR — kinetics, equilibrium, acids/bases (most tested) | ||||||||||
| R2.1 | Kinetics | Rate of reaction — concentration/temperature/surface area/catalysts effects, collision theory, rate expression | ✔ | ✔ | ✔ | ✔ | ✔ | ✔★ | SL&HL | ⭐⭐⭐⭐⭐ |
| R2.2 | Equilibrium | Chemical equilibrium — Le Chatelier’s principle, Kc expression, effect of conditions on K, Haber/Contact process | ✔ | ✔ | ✔ | ✔ | ✔ | ✔★★ | SL&HL | ⭐⭐⭐⭐⭐ CERTAIN |
| R2.3 | Acids/Bases | Acids & bases — Brønsted-Lowry, strong/weak acids, pH, Ka, Kw, buffer solutions, titration curves | ✔ | ✔ | ✔ | ✔ | ✔ | ✔★★ | SL&HL | ⭐⭐⭐⭐⭐ CERTAIN |
| REACTIVITY 3: ELECTRON TRANSFER — redox, electrochemistry, organic mechanisms | ||||||||||
| R3.1 | Redox | Redox reactions — oxidation states, half-equations, balancing redox, electrochemical series, EMF | ✔ | ✔ | ✔ | ✔ | ✔ | ✔★ | SL&HL | ⭐⭐⭐⭐⭐ |
| R3.2 | Electrochemistry | Electrochemical cells — voltaic cells, electrolysis, Faraday’s laws, galvanic corrosion | ✔ | ✔ | ✔ | — | ✔ | ✔★ | SL&HL | ⭐⭐⭐⭐ |
| R3.3 | Organic Rxns | Organic reaction mechanisms — addition, substitution, elimination; halogenoalkanes, alcohol reactions | ✔ | ✔ | ✔ | ✔ | ✔ | ✔★ | SL&HL | ⭐⭐⭐⭐⭐ |
| R3.HL | Organic (HL) | Advanced organic mechanisms — SN1/SN2, E1/E2, nucleophilic addition, benzene electrophilic substitution HL | — | — | — | — | — | ✔★ | HL | ⭐⭐⭐⭐ HL |
★★ = heavily tested M25 · ★ = confirmed · 🟡 mapped old · 🟢 new syllabus | HL rows greyed in SL view
🟡 M25 Chemistry findings: Equilibrium (R2.2), Acid-Base chemistry (R2.3) and Enthalpy calculations (R1.1) were heavily tested in May 2025. Bonding and VSEPR (S1.4) appeared prominently in MCQ. HL students reported Entropy/Gibbs energy (R1.HL) as a major Paper 2 topic — heavier than expected for a first sitting.
🔴 Top 5 Chemistry MCQ topics — every year
- R2.3 Acids & Bases — pH, Ka, Kw, buffers, titration. Appears in every paper. Know the calculations cold.
- R2.2 Equilibrium — Le Chatelier, Kc expression, Haber/Contact. Most frequently tested Reactivity topic.
- S1.4 Bonding & VSEPR — Lewis structures, molecular geometry, polarity. Every paper, every level.
- R1.1 Enthalpy calculations — Hess’s law, bond enthalpies, calorimetry. Always tested with calculations.
- S1.2 Electron configuration — electron shells, ionisation energy trends. Consistent across all sittings.
⚗️ Chemistry MCQ technique
- No penalty — attempt every question, even if guessing
- For stoichiometry MCQ: write the mole ratio before calculating — saves time and avoids errors
- Data booklet is allowed — know which page has which formula/value
- For bonding questions: draw Lewis structure mentally or quickly on paper first
- Eliminate clearly wrong answers — often 2 options contain the same error
- HL: for Gibbs energy — remember ΔG negative = spontaneous. Don’t mix up signs.
Paper 1B — Data-Based Questions
🟡 What Paper 1B tests in Chemistry: This paper replaced old Paper 3 Section A. It presents real chemistry data — graphs, spectra, experimental results, kinetics data — and asks you to read, calculate, interpret and evaluate. The chemistry content can come from any section, but the skills tested are always the same: reading graphs, processing data, identifying errors, evaluating experimental design, and applying chemistry to unfamiliar contexts.
🟡 Skills always tested in Paper 1B
- Graph reading — extract values, find gradient, describe trends, identify anomalies
- Processing experimental data — calculating concentration, yield, percentage error
- Interpreting spectra — IR, mass spectra, NMR (identifying functional groups)
- Evaluating experimental design — systematic vs random error, suggest improvements
- Drawing conclusions — link data to theory, state whether data supports hypothesis
- Uncertainty calculations — absolute and percentage uncertainty propagation
⚗️ Experimental contexts from Specimen + M25
- Kinetics experiment — rate vs concentration/temperature graph, order of reaction
- Titration data — equivalence point, buffer region, calculating Ka from graph
- Calorimetry experiment — enthalpy change from temperature data, heat capacity
- Spectroscopy data — IR spectrum functional group identification, mass spectrum
- Electrochemical cell data — EMF vs concentration, Faraday’s law calculation
- Practice old Paper 3 Section A questions (2019–2024) — identical experimental skill set
⚠ Key revision tip for Paper 1B: Every mark in Paper 1B is a skill mark. Practise with old Paper 3 Section A from 2019–2024 — the experimental skills are directly transferable. For graph questions: state the trend precisely using numbers from the graph. For “evaluate the method” questions: always mention at least one limitation AND one improvement.
Paper 2 — Extended Response (Highest mark value)
🔴 Paper 2 is where Chemistry exams are decided. At 44% for both levels, this is the most important paper. It contains short answer questions AND extended response questions covering Structure and Reactivity in depth. Extended questions often require multi-step calculations AND a conceptual explanation. HL students face additional questions on entropy, organic mechanisms, transition metals and electrochemistry.
Paper 2 extended response priorities — Chemistry May 2026
| IB CHEMISTRY — PAPER 2 EXTENDED RESPONSE TOPIC FREQUENCY | May 2025 + Mapped 2019–2024 | ||||||||
| Extended questions require calculation + explanation | Stoichiometry skills needed throughout | HL rows greyed in SL view | ||||||||
| Theme | Topic Area | M21 | M22 | M23 | M24 | M25★ | Avg Marks | May 2026 |
|---|---|---|---|---|---|---|---|---|
| REACTIVITY 2 — Kinetics, Equilibrium & Acids/Bases: most marks available in Paper 2 | ||||||||
| R2.2 | Equilibrium extended — Kc calculation, ICE tables, effect of conditions, Haber/Contact process evaluation | ✔ | ✔ | ✔ | ✔ | ✔★★ | 12–18 | ⭐⭐⭐⭐⭐ CERTAIN |
| R2.3 | Acids & bases extended — pH/pOH calculations, Ka, buffer calculations, titration curve interpretation, indicators | ✔ | ✔ | ✔ | ✔ | ✔★★ | 12–18 | ⭐⭐⭐⭐⭐ CERTAIN |
| R2.1 | Kinetics extended — rate laws, order of reaction from data, Arrhenius equation, mechanism & rate-determining step | ✔ | ✔ | ✔ | ✔ | ✔★ | 10–14 | ⭐⭐⭐⭐⭐ |
| REACTIVITY 1 — Energy & thermochemistry | ||||||||
| R1.1 | Enthalpy calculations — Hess’s law multi-step, bond enthalpy calculations, calorimetry data processing | ✔ | ✔ | ✔ | ✔ | ✔★★ | 10–14 | ⭐⭐⭐⭐⭐ CERTAIN |
| R1.HL | Entropy & Gibbs — ΔG calculations, spontaneity conditions, ΔG° from standard values, Born-Haber HL | — | — | — | — | ✔★★ | 12–16 | ⭐⭐⭐⭐⭐ HL CERTAIN |
| REACTIVITY 3 — Redox, electrochemistry, organic mechanisms | ||||||||
| R3.1 | Redox extended — balancing in acidic/basic conditions, EMF calculations, electrochemical series problems | ✔ | ✔ | ✔ | ✔ | ✔★ | 10–14 | ⭐⭐⭐⭐⭐ |
| R3.3 | Organic reactions extended — reaction pathways, mechanism drawing, identify reagents/conditions, multi-step synthesis | ✔ | ✔ | ✔ | ✔ | ✔★ | 12–18 | ⭐⭐⭐⭐⭐ CERTAIN |
| STRUCTURE — Bonding, periodic trends, stoichiometry always in Paper 2 | ||||||||
| S1.1–S1.4 | Stoichiometry & bonding extended — mole calculations, empirical formula, VSEPR analysis, polarity, properties from structure | ✔ | ✔ | ✔ | ✔ | ✔★ | 10–16 | ⭐⭐⭐⭐⭐ |
| HL topics | Transition metals, SN1/SN2 mechanisms, NMR spectroscopy, advanced electrochemistry — HL P2 always tests these HL | — | — | — | — | ✔★ | 12–18 | ⭐⭐⭐⭐⭐ HL |
🔴 Paper 2 top priorities
- R2.3 Acid-Base — pH, Ka, buffer, titration curve. Every year, highest marks. Know all 4 types of calculation.
- R2.2 Equilibrium — Kc, ICE tables, Le Chatelier. Always extended question, 12–18 marks.
- R1.1 Enthalpy — Hess’s law, bond enthalpy, calorimetry data. Multi-step calculation always tested.
- R3.3 Organic reactions — reaction pathways, mechanisms, synthesis. Consistent across all sittings.
- R1.HL Gibbs energy (HL) — ΔG calculations, spontaneity. Very heavily tested in M25.
✍️ Paper 2 Chemistry technique
- Show all working for calculations — method marks available even if final answer wrong
- State the formula, substitute, calculate — always this order
- For equilibrium questions: write the expression first before substituting values
- For organic mechanisms: draw curly arrows carefully, show electron pair movement
- For “explain in terms of structure/bonding”: name the force/bond, explain why it affects the property
- HL: for Gibbs energy — state sign of ΔG, interpret spontaneity, relate to ΔH and ΔS
About the new IB Chemistry syllabus
IB Chemistry was restructured for first assessment in May 2025. The new syllabus is organised around two overarching concepts: Structure (how matter is built) and Reactivity (how and why reactions occur). This replaced the old 11-topic structure. Paper 3 and all option topics (Materials, Biochemistry, Energy, Medicinal Chemistry) are removed, with some content integrated into SL and HL core.
HL vs SL key differences
- Paper 1: SL = 30 MCQ / HL = 40 MCQ
- Paper 2: SL = 75 marks / HL = 90 marks
- HL additions: Entropy/Gibbs · Hybridisation · Transition metals · Born-Haber · SN1/SN2 mechanisms · NMR · Advanced electrochemistry
- Hours: 150 SL vs 240 HL
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