AP Chemistry FRQ: seven questions, long and short.
Section II of the AP Chemistry exam is seven free-response questions in 105 minutes, worth 50% of your score: three long questions at 10 points each and four short ones at 4. You read them on a screen, write the answers by hand, and work from a periodic table and an equation sheet the exam supplies. For the other subjects, start at the FRQ hub.
The format at a glance
The free response is the second half of an exam that runs 3 hours 15 minutes. The first half is 60 multiple-choice questions in 90 minutes, also worth 50%, so the two sections carry exactly the same weight.
The seven questions, numbered
The AP Chemistry FRQ runs in the same order every year, and College Board prints that order in the directions of every paper: the long questions come first. The order matters more than it looks, because the two groups are worth very different amounts and carry very different suggested times.
Q1–Q3: the long questions
Three questions, 10 points each, 30 points between them, with about 23 minutes suggested for each one. They are multipart. A single scenario runs through parts (a), (b), (c) and on, and the parts lean on each other, so a calculation in one part usually feeds an explanation in the next.
Q4–Q7: the short questions
Four questions, 4 points each, 16 points between them, with about 9 minutes suggested for each. A short question normally has two or three parts and stays inside one idea, which leaves much less room to recover from a misread. Four points can go on a single wrong assumption.
Those suggestions fill the section exactly. Three questions at 23 minutes and four at 9 minutes come to 105, which is all the time there is, so the pacing is tighter than it sounds.
Credit and clock run at almost the same rate. Q1 to Q3 hold 30 of the 46 points, which is 65% of the credit, and College Board hands them 69 of the 105 minutes, which is 66% of the clock. Every minute you spend past 23 on a long question is borrowed from a question paying the same rate.
What each chemistry free response question tests
The chemistry free response pulls from across the course: stoichiometry and the mole; equilibrium with Ka, Kb and Ksp, plus the ICE-table reasoning behind them; acid-base titration curves, buffers and pKa; kinetics and rate laws. It also reaches into calorimetry, bond enthalpies and Hess’s law, into entropy, Gibbs free energy and galvanic cells, and into the Lewis diagrams, VSEPR geometry and intermolecular forces that explain why a substance behaves as it does. A long question will stack several of those inside one scenario.
Topic is not what the section is weighted by, though. College Board weights Section II by science practice and publishes the split: Mathematical Routines is 43–53% of the free response, Argumentation 15–24%, Question and Method 10–16%, Representing Data and Phenomena 8–16%, Model Analysis 5–9%, and Models and Representations 2–4%. Roughly half the section is calculation and a fifth of it is argument.
One of those six is free-response only. The Course and Exam Description prints two science-practice tables, one for each section, and Representing Data and Phenomena appears in the Section II table and not in the multiple-choice table at all. Drawing a Lewis diagram, sketching a titration curve, putting the right units on an axis: those points exist nowhere else on the exam. Skip the drawing tasks when you practice and you are skipping 8–16% of the section.
What College Board gives you on exam day
Two things, and both change how you should prepare. The first is reference material: a periodic table and a sheet of equations and constants, printed on paper and handed out with the rest of the exam materials. You may write on the booklet, but nothing written on it is scored and it does not leave the room.
AP Chemistry is one of nine exams College Board sends printed reference information for. The others are Biology, both computer science exams, all four physics papers and Statistics, so if you are sitting two sciences you will meet a version of this twice. Our guides to the AP Biology FRQ, the AP Physics 1 FRQ and the AP Statistics FRQ cover what each of those papers does with it.
The second is how you physically sit the thing. AP Chemistry is a hybrid digital exam: you answer the multiple choice and read the free-response questions in Bluebook, then handwrite your answers in a paper booklet. Only what is in that booklet is scored. Scratch work is not, so anything you want credit for has to be copied across before time runs out. College Board’s AP Chemistry exam page is where the delivery details and the approved calculator list live.
AP Chem FRQ scoring: how the rubric awards points
Points come in three flavors: the correct setup, the calculation, and the explanation. Every question has a published scoring guideline that says what each individual point requires, and trained AP Readers award them one at a time. Nothing is deducted for a wrong attempt, so partial credit is the whole game. Many parts award a point for the work even when the final number is off, so dimensional analysis written out on the page is worth the seconds it takes.
Significant figures matter on reported answers. College Board’s own definition of the task verb Calculate builds units and significant figures into what a calculation is, so this is not a marker’s preference. And when a question asks why, the rubric wants particulate-level reasoning, something like “the stronger acid dissociates more completely”, rather than a restatement of the result.
An early mistake also does not automatically cascade. Scoring guidelines routinely award a later point for an answer that is consistent with what the student wrote earlier. The sample guideline in the Course and Exam Description gives a point for a bond angle consistent with the Lewis structure the student drew, whether or not that structure was right. A part you are unsure of is still worth attempting, because the parts after it are scored against your work rather than against the ideal answer.
The verbs are not interchangeable either. College Board publishes the ones it uses in free-response questions, and Calculate, Describe, Determine, Estimate, Explain, Identify, Justify, Make a claim, Predict and Represent each ask for something specific.
A worked example
None of this is College Board material. It is a question written for this page, in the shape of a short one, with the points marked where a scoring guideline would put them.
A 0.100 M solution of a weak acid, HA, has a pH of 3.00 at 25 °C. Acetic acid has Ka = 1.8 × 10−5.
- (a) Calculate the hydronium ion concentration.
pH 3.00 gives [H3O+] = 10−3.00 = 1.0 × 10−3 M. One point, for the value with units and to the right number of significant figures. - (b) Calculate Ka for HA.
HA ionises one to one, so [A−] also equals 1.0 × 10−3 M, and the acid left over is 0.100 − 0.001 = 0.099 M. Then Ka = (1.0 × 10−3)2 / 0.099 = 1.0 × 10−5. Two points, one for the correct setup and one for the value. The setup point survives an arithmetic slip; the value point does not. - (c) Is HA a stronger or weaker acid than acetic acid? Justify your answer.
Weaker, because its Ka is smaller, so at the same concentration it dissociates less. One point, for the claim and the reason. “Weaker” on its own earns nothing.
Four points, three parts. Part (c) is also where consistency scoring shows up: it is marked against the Ka you calculated in part (b), so a student who slipped in (b) and reasoned correctly in (c) still takes the point.
Where students lose points
How to practice AP Chemistry free response questions
Pull the released AP Chemistry free response questions from College Board along with the matching scoring guidelines, and start with the long questions, because those carry the most points. Grade yourself honestly against the rubric.
Two things are worth being strict about. Set the timer to 23 minutes and stop when it goes, even mid-part, because the skill you are practicing is finishing rather than solving. And when you mark yourself, award the point only if the response would earn it from someone who has never met you, which is the standard an AP Reader is applying. Once you have a raw score, the AP Chem score calculator will translate it into a projected 1–5.
Frequently asked questions
Quick answers, checked against College Board.
Do I have to answer the AP Chemistry FRQ questions in order?
No. Q1 to Q3 are the long questions and Q4 to Q7 the short ones, but you can move between them freely until time expires. The on-screen clock turns red when five minutes remain, and the proctor gives no spoken warnings, so that color change is the only prompt you get.
Is the calculator policy different for the AP Chem FRQ?
No. A scientific or graphing calculator is allowed on both sections, and College Board recommends one for both. You get a built-in Desmos calculator in Bluebook and may also bring up to two approved handhelds. A four-function calculator is allowed but not recommended. Unlike AP Biology and AP Environmental Science, AP Chemistry carries no 2027 restriction on handhelds with storage.
Do I write my chemistry free response answers in pen or pencil?
Either. College Board allows a pencil or a pen with black or dark blue ink. You read the questions on screen and handwrite the answers in a paper booklet, and only what is in the booklet is scored, so anything worked out on scratch paper has to be copied across.
How many points do I need on the AP Chemistry FRQ for a 5?
Nobody can tell you, because College Board does not publish cut scores or a raw-to-composite conversion for AP Chemistry. What is fixed is the arithmetic underneath: Section II is 46 raw points and half of the exam. Any 1 to 5 you see before results day, including ours, is an estimate.
What does "justify" mean on an AP Chem FRQ?
More than explain. College Board prints the task verbs it uses, and justify asks for evidence plus the reasoning that connects that evidence to the claim. A correct answer with no reason attached is the most common way to lose a justification point.