Master the IB Chemistry Higher Level exam on the 2023 syllabus. Longer papers, the HL extensions of every theme, command terms, marking criteria, Paper 1B data skills, and the Scientific Investigation IA — everything you need to score top marks.
240 teaching hours • Paper 1 (1A + 1B) + Paper 2 • 1 internal assessment
Know exactly what each component tests at HL and how to maximise your marks.
What to expect:
Key Tips
Easy Marks
Watch Out
What to expect:
Key Tips
Easy Marks
Watch Out
What to expect:
Key Tips
Easy Marks
Watch Out
Command terms tell you exactly what the examiner expects. Filter by Assessment Objective (AO).
Every formula printed in your official booklet, organised by topic. Know exactly which ones are given — and which ones you need to memorise.
Free — no account needed
Match your answer depth to the marks available.
Example questions:
Always write the relationship and the substitution on separate lines — you earn the method mark even when the final number is wrong.
Example questions:
A slip in part (a) usually only costs one mark — keep going and use your own answer; ECF protects every later part.
Example questions:
A missing or wrong unit, or a wildly wrong number of significant figures, loses the final mark even when the value is correct.
Example questions:
Never work backwards from the printed answer — derive it forward, and in "show that" quote one extra significant figure to prove you reached it.
These concepts appear throughout Chemistry HL exams. Master them to score higher.
Before any stoichiometry calculation, write and balance the chemical equation. The mole ratio comes straight from the coefficients, so an unbalanced equation gives the wrong ratio and the wrong final answer every time.
Most quantitative chemistry runs through moles. Convert masses, volumes, and concentrations into moles first, apply the mole ratio, then convert back to the quantity the question asks for. Keep n = m / M and n = c × V at your fingertips.
Every final answer needs a unit and a sensible number of significant figures (usually matching the data, 2–3 s.f.). Watch concentration units (mol dm⁻³), energy units (kJ mol⁻¹), and only round at the very end.
Atomic radius, ionisation energy, electronegativity, and reactivity all follow predictable patterns across periods and down groups. Reason from the structure of the periodic table rather than memorising every value in isolation.
The chemistry data booklet is provided in every paper and holds the constants, equations, the periodic table, and characteristic IR / ¹H NMR / mass-spectrum data. Learn where each table lives so you never waste time hunting for a value mid-exam.
Paper 1B is data-based: interpreting spectra, plotting with error bars, drawing best-fit lines, propagating uncertainties, and suggesting method improvements. These experimental skills also carry the Internal Assessment, so drill them early.
Learn from others' mistakes. These cost students marks every exam session.
Forgetting units or quoting too many significant figures
End every final answer with the correct unit and round to a sensible number of significant figures (usually 2–3, matching the data). A missing unit loses the final mark.
Using an unbalanced equation for the mole ratio
Balance the equation before reading the ratio. The coefficients give the ratio of reacting moles — an unbalanced equation feeds a wrong ratio into the whole calculation.
Confusing concentration, moles, and mass
Keep the relationships straight: n = m / M links mass and moles, n = c × V links concentration and volume. Convert everything to moles first, then back to what is asked.
Drawing a Lewis structure without lone pairs or wrong electron count
Count the total valence electrons, place bonding pairs, then add lone pairs until every atom satisfies the octet (or its exception). A missing lone pair changes the shape and loses marks.
Mixing up units before substituting
Convert to consistent units first — cm³ to dm³ for concentration, grams to moles via molar mass, °C to K for gas-law work — before putting numbers into a relationship.
Getting the sign of an enthalpy or energy change wrong
Exothermic changes release energy and are negative (ΔH < 0); endothermic changes absorb energy and are positive. Decide the direction first, then attach the correct sign.
Writing a one-word answer to "explain", "discuss", or "evaluate"
These AO3 command terms need reasoning. Link each point to a chemistry principle with a because-statement, and for "discuss"/"evaluate" give both sides before a judgement.
Working backwards from the printed answer in "show that"
Derive the result forward from first principles and quote one extra significant figure beyond the given value to prove you actually reached it.
20% of final grade • ≤ 3,000 words
A single individual investigation in which you plan and carry out your own experiment on a chemistry research question, then write it up as a report. SL and HL students do the same task, marked on the same four criteria out of 24 — SL allows about 10 hours and HL about 20.
Marking Criteria
Tips for Top Marks
Apply these exam skills with our Chemistry HL practice questions. Get instant AI feedback that shows exactly what scored marks and how to improve.