 Okay, the next one asks, iron solidifies in a body centered cubic structure. The side of the cubic cell of iron for iron is 287 picometers, what is the density of iron in grams per cubic centimeter? So notice cubic centimeter picometers. So we're gonna have to do some conversions here, okay? So anyways, let's write down what the problem tells us. So body centered cubic, so let's just draw that structure, the cube, in itself. So recall, there's gonna be one on each of the corners, one atom on each of the corners, just one in the middle. So, and we do, well, let's remember, well it gives us S, right? So S is 287 picometers. But we have to remember the formula for density. So density equals Z times molar mass over side cube, Z is the lattice point, times Avogadro's number. And it's asking us for density, so that's nice. So remember, Z for a body centered is gonna be A times 1A plus that one in the center. So it's gonna be two. So you can just memorize two or do that every time. So it's always gonna be the same for body centered, right? There's the three that you know, right? Simple body centered face. Okay, so, molar mass, well, we're looking for iron. So how do we get that? Look up at the period of the table. 55.85 grams per mole. Side we know, and Avogadro's number. More than likely it'll be given to you. 6.022 times 10 to the 23rd per mole. Things per mole. So conversion you wanna get used to because these are a lot of times from picometers to centimeters. It is one times 10 to the 10 picometers is 1 cent. So this is gonna be 2.87 times 10 to the negative 8 cent. Once you do enough of these, those two numbers, negative 8, you'll see that a lot. So you get used to it. Okay, so now we just kind of plug and chug, right? So z, what did I say, it's two times molar mass. 55.85 grams per one mole divided by 2.87 times 10 to the negative 8 cent. Cube that whole thing and then multiply that by Avogadro's number. Okay, so hopefully you guys can see that we're going to cancel out moles there. Moles cancel with moles, and we get units of grams per centimeters cubed. Is everybody okay with that? Okay, so 2.87, that's all right, it's upside down. Avogadro's number, two divided by that times 55.85, gives me a density of 7.85 grams per cubic centimeter. Everybody else get that? Yeah. Hopefully. That way I did it right. You guys get that too? Yeah. Any questions on that one before the video dies? It looks like we're losing steam.