I love the chemistry of cooking and have many books on the subject. The only web sites that I have found over the years are geared more for kids. I listed one below. I also have listed a few books you might want to check out. My favorite is On Food and Cooking. It was used as a textbook in a food chem. class I took in culinary school. I still have it and still use it.
On Food and Cooking by Harold McGee
The Curious Cook: More Kitchen Science and Lore by Harold McGee
The New Kitchen Science: A Guide to Knowing the Hows and Whys for Fun and Success in the Kitchen by Howard Hillman
The Inquisitive Cook (Accidental Scientist)
By A. Gardiner, B. Wilson
Cookbook Decoder or Culinary Alchemy Explained by Arthur Grosser