AP Chemistry review: exam format, the 9 units, and how to study
The AP Chemistry exam is a 3-hour-15-minute test of 60 multiple-choice questions and 7 free-response questions, and the College Board recommends a calculator on both sections. You are given a periodic table and an equations sheet. In 2025, 77.9% of students scored 3 or higher.
What’s on the AP Chemistry exam
The AP Chemistry exam splits evenly into two sections. Section I is 60 multiple-choice questions in 90 minutes, worth 50%, mixing single questions with sets built on lab data, graphs, and particulate-level models. Section II is the free response: 7 questions in 105 minutes, also 50%, made up of 3 long questions worth 10 points each and 4 short questions worth 4 points each. That puts 46 raw points in the free-response half.
A scientific or graphing calculator is allowed on both sections, and the College Board recommends you use one throughout.
A periodic table and a sheet of equations and constants come with both sections, so the exam tests whether you can choose and apply the right relationship, not whether you memorized it. AP Chemistry is also one of the nine subjects whose reference materials arrive as a printed booklet on exam day rather than on screen only.
The whole exam runs 3 hours and 15 minutes in a hybrid format: the multiple choice and the question text sit in the Bluebook app, and your free-response answers go on paper by hand. The two sections reward different things. Mathematical routines carry 35–42% of the multiple-choice section and 43–53% of the free response, while the case-building skill the College Board calls argumentation is worth 15–24% of Section II. Representing data and phenomena, the skill behind drawing graphs and diagrams, is not assessed on the multiple choice at all.
The AP Chemistry units, and what each is worth
The course has 9 units. The percentages below are the College Board’s weighting for the multiple-choice section only, not for the whole exam, because Section II is weighted by science practice rather than by unit. Properties of Substances and Mixtures is the heaviest at 18–22%, Acids and Bases follows at 11–15%, and the remaining seven units sit at 7–9% each.
How AP Chemistry is scored, and what a 5 takes
Your multiple-choice and free-response points are weighted, combined into one raw score, and converted to a composite on the 1–5 scale. The College Board is explicit that this is not a curve: AP exams are criterion-referenced, so every student who meets the criteria for a 3, 4 or 5 receives it, however many students that is. The cut-offs themselves are not published.
In 2025, 168,833 students sat AP Chemistry. 77.9% scored 3 or higher, 17.9% earned a 5, and the mean score was 3.36, a little above the average across all AP subjects. If you have been told this is one of the brutal ones, weigh that against how hard AP Chemistry really is in practice.
To turn a practice raw score into a predicted 1–5, use our AP Chem calculator.
How to study for AP Chemistry
Because the equations are provided, the points come from reasoning: knowing which relationship applies, what each variable means, and how to justify it in writing. Build your review around understanding, and learn the reference booklet well enough to find a formula instantly.
Then work the free response heavily, since it is half the exam and rewards clear justification. Go through past questions against the rubric with our AP Chemistry FRQ guide, drill one unit at a time using the AP Chemistry Progress Check answers, and keep our AP Chemistry formula sheet and cheat sheet close for fast review.
And because representing data is assessed only in the free response, practice the graphing and diagram questions deliberately rather than assuming multiple-choice drilling covers them.
How long is the AP Chemistry exam, and when is it?
The exam takes 3 hours and 15 minutes: 90 minutes for the multiple choice, then 105 minutes for the free response. The College Board has scheduled the 2027 exam for Thursday, May 6, in the session it describes as typically the afternoon, starting around noon local time. Start times vary by school, so confirm the current schedule with your AP coordinator before you plan around it. The College Board’s own exam page carries the date and the duration.
AP Chemistry is one of many courses covered here end to end. You can browse all our AP study guides from the home page.
Frequently asked questions
Quick answers, checked against College Board.
How many questions are on the AP Chemistry exam?
60 on the multiple choice and 7 on the free response. The 3 long questions carry 10 points apiece and the 4 short ones 4 apiece, so three questions decide 30 of your 46 free-response points.
Do I have to memorize the AP Chemistry equations?
No. Both sections come with the constants and formulas you need, plus a periodic table. What the exam actually tests is whether you can pick the right relationship and defend it, so knowing your way around that reference beats knowing it by heart.
Is a calculator allowed on the AP Chemistry exam?
On both sections, yes — and that is a College Board recommendation, not merely permission. You may bring up to 2 approved handheld calculators and also use the Desmos calculator built into Bluebook, in scientific or graphing form. A 4-function calculator is permitted but not advised, and the proctor checks every device before testing starts.
How many units are on AP Chemistry?
There are 9, and they are not equal. Properties of Substances and Mixtures takes 18–22% of Section I on its own, Acids and Bases 11–15%, and the other seven 7–9% apiece. The free response is weighted by science practice instead.
Is AP Chemistry hard?
The reasoning load is what makes it hard rather than recall, because the equations are handed to you: mathematical routines alone carry 43–53% of the free-response score. The outcomes are better than the reputation, though, with 77.9% of students scoring 3 or higher in 2025.
Is the AP Chemistry exam digital?
Partly. Bluebook carries the multiple choice and displays the free-response prompts, but you write those answers out by hand in a paper booklet. Your reference materials are printed too: you may annotate them, nothing you write there is scored, and the proctor takes them back at the end.