"This is the home page of Doc Browns chemistry clinic. This has stuff for all from grade 6 to IB. It has revision notes and lots of interactive quizzes. The IB level stuff is aimed at A level but its still useful. Its not an easy site to navigate though"
"A website for IB chemistry good for revision notes but beware it hasn't been fully updated for the new syllabus. It has lots of useful websites though with with simulations to help with understanding"