For 2013 AP Chem
Source: http://apcentral.collegeboard.com/apc/public/repository/ap08_chemistry_coursedesc.pdf
Each time this review activity loads it will randomly select 25 review questions for a set of nearly 100 questions.
Source: http://www.sciencegeek.net/APchemistry/APtaters/directory.shtml
Each time this review activity loads it will randomly select 25 review questions for a set of about 60 questions.
Source: http://www.sciencegeek.net/APchemistry/APtaters/Unit2Review.htm
Each time this review activity loads it will randomly select 20 review questions for a set of about 60 questions.
Source: http://www.sciencegeek.net/APchemistry/APtaters/Unit4Review.htm
Source: http://www.sciencegeek.net/APchemistry/APtaters/Unit5Review.htm
15 questions
Source: http://www.sciencegeek.net/APchemistry/APtaters/chap17rev.htm