Here’s a useful resource for Chemistry teachers : The Chemical Education Digital Library

The Chemical Education Digital Library(ChemEd DL) is the destination for digital content intended for chemical science education. They aim to be the place where you can contribute, share, and organize chemistry education materials. With oversight provided by the various communities that comprise ChemEd DL, we strive to provide the best of what chemical education has to offer.

Check it out here: http://www.chemeddl.org/