 Okay, so let's go ahead and balance this combustion reaction. So C7HA plus O2 goes to CO2 and H2O, okay? So remember how we do these, okay? So we write down what we've got on each side, okay? So what atoms do we have? C, H, and O, right? Okay? So let's write that down over here, two, C, H, and O, like that, okay? So let's count how many carbons do we have on this side of the reaction? Seven. Seven? How many hydrogens do we have over here? Eight. Eight? And just for fun, how many oxygens? Two. Two? Okay. So the first two, we're going to balance over here and then we're going to get the number of oxygens and then rebalance them over here, okay? So how many carbons do we have here? One. One. How many hydrogens? Two. Two. And oxygens, we're all worried about, right now, okay? But it's okay, right? We have three. So one, two, and three. Okay, so seven carbons, the only thing that has carbon in it over here is carbon dioxide, right? And how many carbons does it have in it? One. One. So how many carbon dioxide are we going to have? Total. We have to have seven carbons. Oh, okay. And there's one carbon in each carbon dioxide. So how many carbon dioxide do we have to have? Eight. Seven, right? Seven times one is seven, right? Okay. So how many hydrogens do we have over here? Eight. Eight. And how many hydrogens are there in water? Two. Two. So how many water molecules total do we have to have? Something times two equals eight. Four. Four, right? Okay, so now let's balance our carbons and hydrogens. See if we have this right amount, okay? So how many carbons altogether do we have on this side? Seven. Seven. So that's the same as over here, right? How many hydrogens do we have altogether over here? Eight. Eight. So that's the same as over here, right? How many oxygens do we have over here? So that's seven times two, right? So that's how many? Fourteen. Fourteen plus? Four. Four. So how many is that? Eighteen. Eighteen. So what times two equals 18? Nine. Nine. So we're going to put a nine there, okay? So like that, okay? Okay, so we got seven. Seven. Check. Eight. Eight. Check. Eighteen. Eighteen. Okay? So that's how you do combustion reactions. Balance your carbons and hydrogens on this side, then go back over here and balance your oxygens, okay? Any questions on that one? Wonderful.