If you take IB or A-Level Chemistry and you're wondering whether to sit AP Chemistry too, the first question is simple:
"How much of AP Chemistry do I already know?"
I matched every topic in the AP Chemistry Course and Exam Description against the IB Chemistry guide and the Cambridge 9701 syllabus. The percentages below are my estimates, weighted by each AP unit's share of the exam.
At a glance
| Your course | Overlap with AP Chemistry | Rough prep time |
|---|---|---|
| IB Chemistry HL | about 85% | 2–3 months |
| A-Level (through A2) | about 85% | 2–3 months |
| IB Chemistry SL | about 60% | 3–5 months |
| A-Level (AS only) | about 60% | 3–5 months |
| Alongside school classes | – | 4–6 months |
| During IGCSE | – | 6–8 months |
💡 Prep time varies a lot from student to student. If your basics (moles, equilibrium) are solid, aim for the lower number. If they're shaky, plan for the higher one.
If you take IB Chemistry HL
You already cover entropy and Gibbs free energy, rate laws and reaction mechanisms, equilibrium calculations, weak acids, buffers, titration curves and standard electrode potentials.
What you need to add:
- Ksp, the common-ion effect, pH and solubility → AP Units 7–8
- Photoelectron spectroscopy (PES) → AP Unit 1
- The Beer–Lambert law → AP Unit 3
- Nonstandard cell potential → AP Unit 9
- Thermodynamic vs kinetic control, coupled reactions → AP Unit 9
NMR, organic mechanisms and transition metals barely appear on the AP exam, so you can skip them while preparing for AP.
If you take IB Chemistry SL
The basics overlap (moles, bonding, enthalpy, Le Châtelier), but much of what IB saves for HL is core content in AP.
- Entropy and Gibbs free energy → AP Unit 9
- Rate laws, reaction order, reaction mechanisms → AP Unit 5
- Reaction quotient (Q), equilibrium calculations → AP Unit 7
- Ka, pKa, weak acid pH, buffers, titration curves → AP Unit 8
- Standard electrode potential, E°cell and ΔG° → AP Unit 9
- Hybridization, formal charge, resonance → AP Unit 2
- Plus everything HL students need to add (Ksp, PES, Beer–Lambert)
💡 As an SL student, expect AP Units 8 and 9 to be mostly new. Unit 8 (Acids and Bases) alone is 11–15% of the exam.
If you take A-Level Chemistry (through A2)
A2 already covers Ksp, buffer pH calculations, Gibbs free energy, electrode potentials with the Nernst equation, and rate equations.
- PES, the Beer–Lambert law, photon energy → AP Units 1 and 3
- Reaction quotient (Q), ΔG° = −RT ln K → AP Units 7 and 9
- Kb and Ka × Kb = Kw (not examined in 9701) → AP Unit 8
- Using ln[A] and 1/[A] graphs to find reaction order → AP Unit 5
- Thermodynamic vs kinetic control, coupled reactions → AP Unit 9
If you've only finished AS, Ksp, buffers, Gibbs free energy and electrode potentials are all still ahead of you in A2, so the overlap drops to about 60%.
Practise FRQs whatever your course
The AP Chemistry exam has 60 multiple-choice questions (90 minutes, 50%) and 7 free-response questions (105 minutes, 50%). Many FRQs ask you to draw particulate diagrams or explain with claim, evidence and reasoning. Knowing the content isn't enough if the answer format is new to you, so practise past FRQs alongside the official scoring guidelines.
Check the exam dates
The 2027 AP Chemistry exam is on Thursday, May 6. IB final exams are also in May, so IB students usually find it easier to take AP in May of DP1 (Grade 11). If your school teaches the HL content in DP2, you'll need to study Units 8 and 9 on your own before a DP1 AP exam.