AP Chemistry covers 9 units, from Atomic Structure & Properties to Thermodynamics and Electrochemistry. Use this hub for unit study guides, topic review, FRQs, key terms, cheatsheets, score calculators, practice exams, and exam prep.
AP Chemistry covers 9 units, from Atomic Structure & Properties to Thermodynamics and Electrochemistry. Use this hub for unit study guides, topic review, FRQs, key terms, cheatsheets, score calculators, practice exams, and exam prep.
Get the big picture: what AP Chemistry covers, how it is scored, and how the units connect.
read the overviewStart with the scoring requirements, then choose the guides that match your current project.
browse guidesOpen the unit you are studying now and review its guides, practice, and key terms.
browse all 9 unitsAP Chemistry covers 9 units, from Atomic Structure & Properties to Thermodynamics and Electrochemistry. Use this hub for unit study guides, topic review, FRQs, key terms, cheatsheets, score calculators, practice exams, and exam prep.
Use moles, molar mass, and mass spectra to analyze composition
Predict molecular geometry and polarity with Lewis structures and VSEPR
Balance equations and run stoichiometry for reactions and titrations
Write rate laws and interpret reaction mechanisms and energy profiles
Solve equilibrium, acid-base, and buffer problems with K, Q, and pH
Connect Gibbs free energy, cell potential, and electrolysis
The AP Chemistry exam runs 3 hours and 15 minutes and splits evenly between multiple-choice and free-response. Here is how the sections break down.
| Section | Questions | Time | % of Score |
|---|---|---|---|
| Section I – Multiple Choice | 60 | 90 min | 50% |
| Section II – Free Response | 7 | 105 min | 50% |
Total timed testing time: 195 minutes.
The course is organized into 9 units. The percentages below are the College Board exam weights, so you can see which units carry the most multiple-choice points. Open each unit for its study guide, topic pages, key terms, and practice questions.
Unit 1 of AP Chemistry is about what atoms are made of and how that structure explains everything else in the course.
AP Chemistry Unit 2 is about how the structure of a compound, meaning how its atoms or ions are arranged and bonded, explains the properties you can actually measure.
AP Chemistry Unit 3 is about one big idea, that the strength of attractions between particles explains almost everything you can observe about a substance, from its boiling point to whether it dissolves in water.
AP Chemistry Unit 4 covers chemical reactions, which means writing balanced and net ionic equations, classifying reactions as acid-base, redox, or precipitation, and using stoichiometry to calculate how much reactant or product is involved.
AP Chemistry Unit 5, Kinetics, is the study of how fast reactions happen and what controls that speed.
AP Chemistry Unit 6, Thermochemistry, is all about tracking where energy goes when matter changes, whether ice melts in your drink or methane burns in a stove.
AP Chemistry Unit 7 covers chemical equilibrium, the dynamic state where a reversible reaction's forward and reverse rates are equal, so concentrations stop changing even though both reactions keep running.
AP Chemistry Unit 8 covers acid-base chemistry, which is really equilibrium chemistry (Unit 7) applied to one specific reaction type, the transfer of a proton.
AP Chemistry Unit 9, Thermodynamics and Electrochemistry, answers the question every chemist eventually asks about a reaction: will it actually happen?
These trends come from real Fiveable practice data, so you can see what students are reviewing, which topics need extra attention, and how written practice can improve over time.
Miss rate is based on high-volume AP Chemistry multiple-choice practice.
Average MCQ accuracy by student practice volume across 3,079 AP Chemistry students.
Among AP Chemistry FRQ responses that students retried on Fiveable, average scores rose from 46% on the first attempt to 68% on the latest attempt.
practice AP Chemistry FRQs →These guides collect important exam skills, big ideas, essay tasks, and other subject-specific resources.
4 guides
16 guides
Consistency matters more than any single session in AP Chem. Review each unit as you finish it, then work practice problems before moving on so concepts lock in while they are fresh. Keep a running summary of formulas, definitions, and reaction types organized by unit. Spend extra time on the highest-weight content, especially Unit 3 and Unit 8, plus the units that trip you up like Unit 7 equilibrium and Unit 9 thermodynamics and electrochemistry. As the exam nears, shift to timed multiple-choice sets and full FRQ practice, writing out complete explanations and checking units and significant figures every time.
Read the unit guide and outline the key concepts and equations
Work topic-level practice questions right after each class topic
Drill multiple-choice sets mixing models, math, and argumentation
Write full FRQ responses, including justifications and labeled units
Review mistakes and rebuild any weak topics before the next unit
Run a timed mixed section to practice exam pacing
Use the question types below to plan written-response practice and connect exam guides to timed FRQs. Open an example prompt to practice that question type right away.
| Question | Focus | Points | % of Score | Example prompt |
|---|---|---|---|---|
| FRQ 1 | Long Answer | 10 | 11% | Heat energy and reaction potential energy diagrams |
| FRQ 2 | Long Answer | 10 | 11% | Galvanic cell with chromium and silver electrodes |
| FRQ 3 | Long Answer | 10 | 11% | Molecular structure and formal charge minimization |
| FRQ 4 | Short Answer | 4 | 4% | Activation energy and catalyst effects on reaction pathways |
| FRQ 5 | Short Answer | 4 | 4% | Galvanic cell reactions and electrode mass changes |
| FRQ 6 | Short Answer | 4 | 4% | Vapor pressure and gas behavior of volatile compounds |
| FRQ 7 | Short Answer | 4 | 4% | Atomic mass calculations and ionization energy trends |
Find every unit and topic guide in one place.
AP Chemistry covers atomic structure, molecular and ionic bonding, intermolecular forces, kinetics, thermodynamics, equilibrium, acids and bases, and electrochemistry.
Study AP Chem by unit so the equations, models, and lab ideas stay connected. Then use practice questions and key terms to reinforce calculations, trends, and common mistakes.
Use Fiveable's AP Chemistry FRQ practice for AP-style free-response questions with AI-supported scoring on calculations, explanations, and experimental reasoning.
Start with the unit where your calculations or conceptual explanations break down most often. For exam review, revisit equilibrium, acids and bases, and other units that combine multiple earlier ideas.