 OK, so let's try the last gram slaw problem that we're going to do today. So you have a mixture of neon and an unknown gas. If the rate of effusion of neon is 4.35 moles per minute and the rate of effusion of the unknown gas is 9.76 moles per minute, what is the molar mass of the unknown gas? And what is the identity of that unknown gas? OK, so let's attempt this one together. So again, what law are you going to use here? What equation? Grams law. Yeah, very good. And do you guys remember how to do that again? So it's what? 1 over 3, 2, 3, 2 equals rary of the molar mass of q2 over the molar mass of 1. So we're looking, well, we've got molar mass of neon. That's really given to us on the periodic table. So let's look up on the periodic table. We'll say 20.18 grams per mole. And we're looking for the molar mass of the unknown gas. So in light of that information, you might want to arrange this equation to make it easier on yourself. So it would be easiest to find this molar mass easier than this. So let's put the unknown gas there. Is everybody OK with doing that? So say, molar mass of unknown, unknown, and this is going to be neon. OK? So again, I don't like to mess with these kind of square root symbols because they're kind of cumbersome in my mind. So I'm just going to make this an exponent, the 1 half. Hopefully everybody's OK with that right now. OK, so we're looking for the molar mass of that unknown gas. So let's isolate that variable. So how are we going to do that? How are we going to get rid of that 1 half of that square root there? What will we do? Yeah, we've got to square both sides, right? So square, and then when we square this side, it's just going to lose that. Is everybody OK with doing that? OK, so now let's multiply both sides by the molar mass of neon. OK, so when we do that, the molar mass of the unknown gas. So is everybody OK with that sort of arrangement? OK, so now it's just a plug and chug type problem. And then, of course, at the end, we're going to kind of have a guessing game and see what gas that really is. OK, so the rate of neon is going to be 4.35 moles per minute divided by 9.76 moles per minute. Where are that? And multiply it by 20.18 grams per mole. OK, so hopefully you can see moles per minute cancels there. Is everybody OK? Let's just plug into our calculator. 4.35 divided by 9.76 square times 20.18. So what are our units going to be here? Yeah, grams per mole. And did anybody get the number? What did you guys get? 4.008. OK, so these don't always come out to be exactly what you would expect them to be. But could anybody identify what gas it might be? Neolium, probably. So look at that. And if we look at the periodic table, the identity is probably neon. So is everybody OK with doing something like that? So that's just rearranging it in another way. So I thought I'd show you both. Good job, guys.