This video covers a very specific type of problem which most chemistry students find confusing: labeling the oxidizing and reducing agents. What makes it tough is that the compound that gets oxidized is also the reducing agent, and the compound that gets reduced is the oxidizing agent. Confused yet? You're not the only one.
If you do not have an account, you should get one, because it is awesome! You can save a playlist for each test or each chapter, and save your "greatest hits" into a "watch right before the final" list (not that we recommend cramming, but when in Rome...)