I've graded a lot of practice FRQs over the years, and the pattern is always the same. Two students land on the exact same final number, and one gets full credit while the other gets half of it. The difference is almost never the chemistry. It's what got written down along the way.
Manage the clock on purpose
You get roughly 105 minutes for all 7 free response questions. That works out to about 20 minutes for each of the 3 long questions and 10 minutes for each of the 4 short ones, with a couple of minutes up front to skim everything and decide your order. Start with whichever question you feel strongest on. That builds momentum and banks points early, before fatigue sets in on the harder ones later in the section.
Answer every part, even the ones you're unsure about
Each long question is broken into parts, usually labeled a through g or further, and each part is graded on its own. Skipping a part you're unsure about guarantees zero points for it. A partial attempt, even a shaky one, at least gives a grader something to award credit for.
Many questions also use consequential scoring. If you get part a wrong but correctly carry that wrong number through the right method in part b, part b can still earn full credit. That means one mistake early on doesn't have to cost you the rest of the question.
Show the reasoning, not just the number
This is the single biggest gap between a good answer and a great one. Points on the AP Chemistry rubric are typically awarded for specific steps: writing the correct formula, setting up the calculation with the right numbers in the right places, including correct units, and stating a clear chemical justification when the question asks for one. A correct final answer with none of that shown often earns partial credit at best, sometimes none.
If a question asks you to explain or justify something, that sentence is not optional decoration. It's usually worth its own separate point, completely apart from any calculation in the same part.
Reference the actual data in the problem
Graders are specifically trained to look for responses that connect back to the numbers, graphs, or observations given in the question itself, rather than a generic textbook explanation. If a question shows you a titration curve, a strong answer mentions where on that specific curve the reasoning applies, not just the general concept in isolation.
Write like the grader can't read your mind
AP graders score exactly what's on the page. If the reasoning exists in your head but never made it into a full sentence, it doesn't earn the point. This is especially true for conceptual, non math parts: a vague answer that's technically not wrong still won't earn credit if it never clearly states the actual chemistry idea being tested.
This is most of what I do in a live class
Practicing real released FRQs together, out loud, and grading them against the actual scoring guidelines line by line, so students see exactly where their own answers were losing points before it matters on the real exam.
Questions I get asked about FRQs
How long should you spend on each AP Chemistry FRQ?
Roughly 20 minutes for each of the 3 long questions and 10 minutes for each of the 4 short ones, with a couple of minutes at the very start to skim all 7 and decide where to begin.
Do you lose points for a wrong answer if the work is correct?
Often no. Many FRQs use consequential scoring, meaning if an earlier part is wrong but a later part correctly uses that wrong number with the right method, the later part can still earn full credit.
Why do FRQ scores feel lower than expected even when the final answer is right?
Because most of the available points are for the reasoning and setup, not the final number. A correct answer with no shown work or explanation often earns partial credit at best.