 Okay, so we've got this problem that we just did and we figured out that we have 2.9 moles of water Right, but we want to figure out if that's how much water we started with How much oxygen did we create moles of oxygen amount is moles, right? So when I say how much I'm looking for moles. Is everybody okay with that? So if I were to want to figure out how many moles of oxygen I made what would I do to this? Help me out Multiply yeah, very good by the ratio of what? Units I need units I need okay, so what's on the bottom? Everybody tell me Two moles H2o, why'd we put that on the bottom? Cancel out with this moles of H2o, and what are we putting at the top here? One mole of oxygen does that give us the number of moles of oxygen? Yes Everybody cool with that?