Revision guide
IB Chemistry
Structure and Reactivity, the data booklet, and how to stop losing marks on wording.
IB Chemistry's current syllabus is organized around two big ideas — Structure (particulate nature, bonding, periodicity) and Reactivity (energetics, rates, equilibrium, electron transfer, mechanisms) — and the exams move between them constantly. It's a subject where precise vocabulary is worth real marks: examiners distinguish between 'atom', 'molecule', and 'ion', and an explanation that's chemically right but loosely worded often scores partial credit at best.
Two resources define exam success: the data booklet, which you should know like your own notes, and the markschemes, which teach you exactly the phrasing examiners accept. Most Chemistry 6s become 7s through markscheme-literate writing rather than new content.
How you're assessed
Paper 1 (multiple choice + data)
Paper 1A is multiple choice without a calculator-dependent emphasis; Paper 1B asks data-analysis questions tied to experimental contexts. The MCQs are quick but full of distractors built from common misconceptions — practicing them is the fastest diagnostic of weak topics.
Paper 2 (extended response)
Structured short- and long-answer questions across the syllabus. This is where wording precision, balanced equations with state symbols, and multi-step calculations (moles → limiting reagent → yield) carry the marks.
The IA (Scientific Investigation)
One investigation worth 20%, assessed on research design, data analysis, conclusion, and evaluation. Simple chemistry measured carefully beats ambitious chemistry measured badly — uncertainty propagation and honest evaluation are where marks hide.
How to revise
Live in the data booklet
Many questions are answerable directly from booklet data — bond enthalpies, electronegativities, Ka values. Revise with the booklet open so that during exams you reach for the right table reflexively.
Write definitions like the markscheme
Keep a running list of definitions and 'explain' answers phrased exactly as markschemes phrase them. 'Electronegativity is the ability of an atom to attract a bonding pair of electrons' earns the mark; a fuzzy paraphrase may not.
Drill multi-step mole calculations
Limiting reagent, percentage yield, gas volumes, titration back-calculations: practice them as full chains until the structure is automatic. Show every step — method marks survive arithmetic slips.
Connect Structure to Reactivity
The syllabus is explicitly cross-linked: bonding explains volatility, electronegativity explains mechanism choice. Practice questions that cross units, because the exam will.
Mistakes examiners see every year
Omitting state symbols in equations where they're required (especially energetics).
Mixing up endothermic/exothermic sign conventions for enthalpy changes.
Describing observations ('colourless solution') imprecisely — 'clear' is not 'colourless'.
Quoting electron configurations without checking the exceptions and ion cases.
Treating the IA evaluation as an afterthought — it's a heavily weighted criterion.
What's in the syllabus
Structure 1: Models of the particulate nature of matter
Moles and molar mass · Empirical and molecular formulae · Limiting reagents · Ideal gases · Atomic structure · Electron configuration
Structure 2: Models of bonding and structure
Ionic bonding · Covalent bonding · Lewis structures · VSEPR · Polarity · Intermolecular forces · Metallic bonding
Structure 3: Classification of matter
Periodic trends · Functional groups · Isomerism · Mass spectrometry · Infrared spectroscopy · NMR spectroscopy
Reactivity 1: What drives chemical reactions?
Enthalpy changes · Hess cycles · Bond enthalpy · Entropy and spontaneity · Equilibrium · Le Chatelier's principle
Reactivity 2: How much, how fast and how far?
Rates of reaction · Rate expressions · Mechanisms · Acids and bases · pH calculations · Buffers · Titration curves
Reactivity 3: Mechanisms of chemical change
Redox · Electrochemical cells · Electrolysis · Organic mechanisms · Nucleophilic substitution · Addition and condensation polymers
Frequently asked questions
Is HL Chemistry worth it for medicine?
Most medical schools require or strongly prefer HL Chemistry, so for medicine applicants it's usually non-negotiable. Pair it with HL Biology and the workload is heavy but the content overlaps usefully.
How do I revise organic chemistry?
Build reaction maps: one page per functional group showing every reaction in and out, with conditions and mechanisms (HL). Redraw the maps from memory weekly — recognition is not recall.
What makes a good Chemistry IA topic?
A focused variable with a measurable effect and a real chemical explanation: rate vs. temperature with a clear activation-energy analysis beats a vague multi-variable product comparison.
Put this guide into practice
Everything above — topic-filtered practice questions, spaced-repetition flashcards, and a syllabus checklist for Chemistry — is free on Baccly.
Start free