If you're taking chemistry in high school it doesn't have to be in the 11th grade, but it seems like most schools offer 10th grade biology, 11th grade chemistry, and 12th grade physics. There are a lot of topics covered in 11th grade chemistry. For the most part these are the same concepts as you'll see if you take college chemistry, though sometimes 11th grade chemistry doesn't quite make it to nuclear chemistry or introductory physical or organic chemistry. Also, college chemistry covers more about qualitative and quantitative analysis.
Anyway... here's a typical list of 11th grade chemistry topics
. I've been going through adding links to online coverage of each topic. I'm adding additional pages that focus specifically on the topics, so when I'm doing linking the page will essentially be a high school chemistry textbook, except online and without those really comfortable lab bench stools.