HELP! I've been having problems with Chemistry the past semester and a half, but stoichiometry is the hardest thing yet. Here's the problem: Aluminum oxide is formed from the reaction of metallic aluminum with oxygen gas. How many moles of Aluminum are needed to form 3.4 moles of Aluminum oxide? I've looked around the site and found a thread on it, but it didn't help me completely. So far, I have the balanced equation: 4Al + 3O2 --> 2Al2O3. The ratio is 4/3, but where do I go from there?