"Just do practice tests" is common advice that misses the more important detail, which is that how you use a practice test matters just as much as how many you take.
Where to find real practice material
College Board publishes real, released free response questions and full scoring guidelines directly on AP Central, which is the single most authoritative source available, since it's the exact rubric real graders use. For multiple choice practice, released full exams from past years are the most representative, since third party questions can drift from the actual style and difficulty of the real exam.
How to actually use a practice test
- Time yourself honestly. The real exam is 3 hours and 15 minutes total, and building stamina for that length matters as much as knowing the content.
- Grade free response against the real scoring guidelines, line by line, not just against whether the final answer matches. Most of an FRQ's points come from the reasoning shown, not the number alone.
- Keep a running list of what actually went wrong, not just a score. A percentage tells you where you stand; a mistake log tells you what to fix.
A realistic schedule
Full length, timed practice tests are most valuable in the final ten to twelve weeks before the exam, once most content has been covered. Earlier in the year, shorter topic specific practice, focused on whatever unit is currently being taught, builds the same skills without the time commitment of a full mock exam every week.
Practice with real feedback attached
A diagnostic test that actually shows which topics need work is a faster starting point than jumping straight into full length practice exams blind.
Common questions
Where can you find real AP Chemistry practice questions?
College Board's own AP Central site publishes released free response questions along with the actual scoring guidelines used by real graders, making it the most authoritative source available.
How often should you take full length practice tests?
Full length, timed practice tests are most valuable in the final ten to twelve weeks before the exam. Earlier in the year, shorter topic specific practice tied to whatever unit is currently being covered is more efficient.
What matters more, the number of practice tests or how they're reviewed?
How they're reviewed. Grading free response answers against the real scoring guidelines and keeping track of specific recurring mistakes moves a score more than simply taking more tests without that review step.