 So, let's do this one for the last problem of the day. Same sort of thing, stoichiometric relationship with the gas loss. Okay? So, let me read the problem to you guys. So, silver two oxide decomposes via the following balance chemical equation. This one, two silver two oxide solid goes to four silver solid plus oxygen. So, this one you can see that actually you can see the decomposition because you get silver out of it. Okay? So, you'll see the silver color. This one. What volume of oxygen will be formed at 546 Kelvin and standard pressure by the dissociation of 0.2 moles of silver two oxide? So, there's a lot of weird phrasing in that. So, that's why I decided to do this one. Okay? So, let's write down what they're talking about. So, it says what volume of oxygen will be formed? So, volume of oxygen is what we're looking for. 146 Kelvin. Okay? So, that's going to be the temperature of the oxygen at 546. So, that was nice of them. They didn't make us convert it from self-sense. And standard pressure. So, if you don't know what standard pressure is, you're again kind of swimming up the creek on this one, you know? So, standard pressure, oxygen at standard pressure is going to be 1.008 N. So, that's something you're going to want to remember. By the dissociation of 0.2 moles of Ag2O or silver two oxide. So, the number of moles of Ag2O is what did I just say? Is it 0.20? So, that's all fine and good, but it doesn't tell you anything about the number of moles of oxygen, right? So, we needed to use the stoichiometric relationship that we've developed from the balanced chemical equation to figure out, well, how many moles of oxygen do we actually have in this reaction? Okay? And this, of course, is if all of the 0.2 moles of silver two oxide went to completion. And you'll get more of that in the next section when we talk about percent yields and things like that, okay? So, anyways, let's figure out the number of moles of oxygen. So, the number of moles of oxygen, well, remember, do you remember the stoichiometric relationship that we get from the balanced chemical equation, right? So, why don't you help me out? So, how do we do this? So, the number of moles of oxygen, we're going to have to use this number first, right? So, how many moles? So, 0.20 moles silver two oxide, right? But we're going to have to multiply that by something, because we don't want the moles of silver two oxide, we want the moles of oxygen, right? One mole of oxygen. Very good, yeah. So, when we do that, you can see the moles of silver oxide can't allow, and we're getting this moles of oxygen, okay? So, hopefully, you don't have to do that in your calculator, but if you do, that's all right, because this isn't math class. So, that's how many moles of oxygen we have. So, that's cool, but that doesn't tell us how many liters of oxygen we have, right? So, just for posterity, again, we'll write down that conversion factor, one mole of oxygen to two moles, right? So, the last thing we're going to have to do is use the ideal gas law to figure out the volume of oxygen, okay? So, I guess, before I erase that, let's write down the ideal gas, do you remember the ideal gas law? So, PV equals nRT, right? And what are we looking for in this one? Volume. So, to isolate volume, we're going to have to what? Divide by pressure. Divide both sides by pressure. Pressure cancels there, right? And what's our new equation? V equals nRT over P, right? So, we're looking for the volume of oxygen, right? So, in order to fit the volume of oxygen, we're going to have to know the number of moles of oxygen. Do we know that, right? Yeah, yes, right? What is this one? The gas constant, 0.0821, yeah. Well, here, I'll write that down in a second. Do we know the temperature of oxygen? Yes, and do we know the pressure of oxygen? So, we should be able to find out the volume of oxygen. Okay, I'm going to erase all of this with that, and we'll do that equation over there. So, let's just write down R really quick. And again, I just memorized this because I've done countless problems with that, okay? But remember, we're going to have to expand that when we put it into the formula. So, the volume of oxygen is going to be n. So, n is the amount, number of moles, 0.10 moles. I'm going to erase that now. R, I expand. So, 0.0821 liter ATM, 1 mole kelvin, alright? Times the temperature, which we got. They didn't make us convert it. That's all that's on the top, divided by the pressure of oxygen. Very nice. Just one. So, all we're using that for is to cancel it, you know. Remember that standard pressure. So, if you don't know that, you couldn't do this problem. If you can't, if you don't remember and you remember everything else, try to do the problem, you know, but try to put something on that, you know. Don't just give up. Anyways, so, well, I guess we should cancel our units first, huh? Makes everybody happy. Everybody's like, cancel the units. Okay, let's do it. Cancel any moles, right? Cancel kelvin, right? ATMs cancel. You guys got all those anyways, right? So, I shouldn't, I didn't have to. It's good to show on the video though. 0.1 times 0.02821 is 546 divided by 1. So, I got, how many? So, 2. So, 4.5 liters of oxygen. Is that what you guys got, too? Did you get 4.5 liters? Everybody get it? Yeah. Okay, let's try it one more time. Just, yep, 4.5 liters. Okay, cool. Okay, so are there any questions on this one? You guys think you can do these? Okay, I've got one more in there for you guys on the lecture slide, so I expect you guys to do it. Okay? Okay.