This YouTube Channel has numerous videos on various content (most is honors level, but they give a strong foundation for the skills needed for AP Chemistry)

These are review note guides based on the old AP Exam; most are still relevant. Funding was lost and their wikispace has been discontinued, but you can access the reviews here.

This website has flashcards and key vocabulary from an older version of the Zumdahl textbook

This is a free online textbook written by various professors from around the nation.

This resource has PowerPoints and Review Activities