The following web sites contain additional information on a variety of chemistry topics and/or they have lists of other web sites that provide this information.
Wilton High School Chemistry
Steve Lower's Chem1 Website
High School Chemistry
Chemistry for Students & Teachers
Periodic Table Links
Brian Tissue's Chemistry Hypermedia Project
Frank Lambert's Notes on Entropy and Thermodynamics or
More on Entropy and the Second Law of Thermodynamics from Frank Lambert
Here are some other links that might be helpful or interesting.