AP exams, 9 units
AP Chemistry exam guide
Work through all nine AP Chemistry units with published exam weightings, from atomic structure to electrochemistry.
Follows the fall 2024 course and exam description, from 6 May 2025
Overview
What AP Chemistry covers.
AP Chemistry is a full-year, college-level general chemistry course covering atomic and molecular structure, the behavior of substances and mixtures, reactions, kinetics, thermochemistry, equilibrium, acids and bases, and thermodynamics with electrochemistry. The Course and Exam Description organizes the content into nine units and pairs it with six science practices, several of which are laboratory skills assessed on the free-response section.
The published weightings are unusually lopsided for an AP science course. Unit 3, which covers intermolecular forces, gases, solutions, and spectroscopy, carries far more of the multiple-choice section than any other unit, and acids and bases carries the second largest share. Equilibrium reasoning runs through Units 7, 8, and 9, so time spent making that reasoning automatic pays off three times over.
Arcade Academy is an independent study workspace. Use the official Course and Exam Description for the authoritative content list, and use the unit pages below to organize practice, particularly the multi-step quantitative work the exam rewards.
At a glance
- Total time
- 3 hours 15 minutes
- Section I
- 60 multiple-choice questions in 1 hour 30 minutes, 50% of the exam score
- Section II
- 7 free-response questions in 1 hour 45 minutes, 50% of the exam score: 3 long questions worth 10 points each and 4 short questions worth 4 points each
- Delivery
- Hybrid digital: multiple-choice questions are answered and free-response prompts are read in College Board's Bluebook app, and free-response answers are handwritten in a paper booklet
- Calculator
- A scientific or graphing calculator is permitted on the exam, and a periodic table plus a formulas and constants sheet are provided
- Score scale
- 1 to 5
- Governing body
- College Board
- Who takes it
- High school students taking AP Chemistry for college credit or placement, often as preparation for a science, engineering, or health-professions major.
Scoring
The multiple-choice and free-response sections each contribute half of a composite score, which College Board converts to the reported 1 to 5 scale using cut points set for that year's exam. Because colleges set their own credit and placement policies, the same score can earn credit at one institution and only placement at another.
Exam structure
Units
AP Chemistry covers 9 units. Open one for its topics, published weighting, and section-specific study tips.
Unit 1: Atomic Structure and Properties
7–9%Unit 1 sets up the quantitative and structural vocabulary of the course: moles, composition, electron configuration, and periodic…
6 topics
Unit 2: Compound Structure and Properties
7–9%Unit 2 moves from atoms to bonded structures: ionic, covalent, and metallic bonding, and the geometry that follows from electron…
6 topics
Unit 3: Properties of Substances and Mixtures
18–22%Unit 3 carries the largest published weighting in AP Chemistry. It spans intermolecular forces, the properties of solids…
6 topics
Unit 4: Chemical Reactions
7–9%Unit 4 covers how reactions are represented and classified, and the stoichiometry that quantifies them. Net ionic equations…
6 topics
Unit 5: Kinetics
7–9%Unit 5 is about how fast reactions go and what that reveals about mechanism. It moves from measuring rate and determining rate…
6 topics
Unit 6: Thermochemistry
7–9%Unit 6 covers energy transfer in chemical and physical processes: endothermic and exothermic behavior, heat capacity and…
6 topics
Unit 7: Equilibrium
7–9%Unit 7 develops the reaction quotient and equilibrium constant, the calculations that follow from them, and Le Chatelier's…
6 topics
Unit 8: Acids and Bases
11–15%Unit 8 carries the second largest published weighting in the course. It covers strong and weak acid and base behavior, pH and…
6 topics
Unit 9: Thermodynamics and Electrochemistry
7–9%Unit 9 brings entropy and Gibbs free energy together with the electrochemistry that applies them. It covers thermodynamic…
6 topics
Study strategies
How to work through this exam.
These strategies follow from the exam's own structure. Adapt them to the time you actually have each week.
- Weight your review by the published unit percentages: Unit 3 and Unit 8 together account for roughly a third of the multiple-choice section and deserve proportional time.
- Do multi-step quantitative problems with full unit tracking rather than plugging into remembered formulas, because the free-response section awards points for the reasoning steps.
- Rehearse particulate-level explanations, since the exam repeatedly asks you to justify a macroscopic observation with a drawing or description of what particles are doing.
- Practice writing complete justifications, not just answers; released scoring guidelines award points for the connection between evidence and claim.
- Keep laboratory reasoning in the rotation, including experimental design, error analysis, and interpreting data from an unfamiliar procedure.
- Work at least a few full timed sections to build pacing, since the free-response section is longer than the multiple-choice section and fatigue is a real factor.
Common questions
AP Chemistry questions students ask.
How is the AP Chemistry Exam structured?
The exam runs 3 hours 15 minutes. Section I is 60 multiple-choice questions in 1 hour 30 minutes for 50% of the score. Section II is 7 free-response questions in 1 hour 45 minutes for the other 50%, made up of 3 long questions worth 10 points each and 4 short questions worth 4 points each.
Which AP Chemistry units are hardest?
College Board does not publish a difficulty ranking. Students commonly report that equilibrium, acids and bases, and the thermodynamics and electrochemistry unit demand the most practice, partly because each builds on the ones before it. Use your own practice data to decide where time goes.
How is the AP Chemistry Exam scored?
The two sections contribute equally to a composite score that College Board converts to the reported 1 to 5 scale, with cut points set each year. Individual colleges decide what score earns credit or placement, so outcomes vary by institution.
When do students usually start exam-specific review?
A common pattern is to review each unit as the course finishes it and then begin cumulative, timed practice around February or March for a May exam. Earlier starts mainly help by spreading out repetition of the calculation-heavy units.
What is the calculator policy, and how is the exam delivered?
A scientific or graphing calculator is permitted on the exam, and a periodic table and formulas-and-constants sheet are provided. AP Chemistry is a hybrid digital exam: multiple-choice questions are answered in College Board's Bluebook app and free-response answers are handwritten in a paper booklet. Confirm current policy on the official exam page.
Is Arcade Academy affiliated with College Board?
No. AP® is a registered trademark of College Board, which was not involved in the production of, and does not endorse, this site. Arcade Academy is an independent educational resource, and College Board publications remain the authoritative source on the course and exam.
Before you build the schedule
Exam structures change. Confirm the current format, eligibility, and policies with College Board before you commit to a study plan.
Official exam information opens in a new tabGuide structure last checked against official sources on August 30, 2026.
Markdown version of this guide for citation, offline reading, and language models.
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