This site has an excellent selection of over 900 free AP Chemistry mutiple choice questions. They are organized by unit so that you can review them all or just focus by topic.

This is a huge collection of practice quizzes including chapter review questions and many tests on many specific topics. This is an amazing resource, fully updated for the new test.

A complete midterm test with AP Chemistry multiple choice and free response. Lots of challenging questions in a PDF file. Video solutions are here.

The AP Chemistry Course Description packet has 26 practice questions starting on page 117. Since these are directly from the College Board you should definitely check it out.

This is the student companion site for the popular Chemistry text by Zumdahl. Great interactive quizzes for each chapter. Just select the chapter/topic and click on Tutorial Quiz.

Hundreds of AP Chem questions organized around the 6 big ideas from the updated curriculum. You need to register for access.