 So let's try this, this is law, so it's similar to the last one, except for, instead of solving for the delta H of the reaction, the standard heat of the reaction, we're now solving for one of these heats of reaction up here, okay, so not the one that we're looking for, but actually one of the ones that added up to get the one that we got now. So anyways, recall what we do in order to do this, we have to make sure that everything we've got on this side of the equation is present down here, everything that we have on this side of the equation is present down here, and everything on both, that is on both sides of the equation gets cancelled out, okay. So, I think like Katelyn was saying, this one's pretty straightforward, because if we count the hydrogens, there's two plus one and that equals three. The nitrogens is one, so that equals one, and there's this hydrazine here. That's, well, this is gas, too, I guess, I think, quite good. But, and it didn't, right here and there, okay. So, but that hydrazine, it's cancelled out, and then if we look, we've got two ammonia gas, two ammonia gas, okay. So, these two equations add up fairly nicely to get the delta-heated reaction. So, remember Hess's law is delta-heated reaction is delta H1 plus delta H2, so on and so forth, okay. So, we're solving for delta H1 in this case. So, it's going to be change of H of the reaction minus delta H2. And we have both of those numbers. So, we get 92.2 kilojoules minus 187.6 kilojoules. So, minus, minus, that's a plus, right? 95.4 kilojoules. What is it? Sorry. 95.4 kilojoules. Okay, thanks. 95.4 kilojoules, and it's going to be delta. Is this reaction up here, delta H1, that is showing delta H1? Is that an exothermic or endothermic reaction? Endothermic, right? Because this is actually plus 95.4. So, I know it doesn't ask, but so that means you have to input heat, okay. Are there any questions on this one? Fairly straightforward. Pretty straightforward example that passed this law.