I just want to say thank you to those who created this website! I don't think I could have passed my Chemistry II class without it. I had a teacher who taught using simple example problems but the tests always consisted of very complicated problems. Khan Academy helped me identify and solve even the most complicated problems. The in-depth explanations were most helpful. They gave me a deeper understanding where my teacher just touched on certain areas. I am so grateful to you and I have recommended your site to all of my friends. Again. Thank you! Thank you! Thank you!!!!!!!