 Okay, so now that we've gone ahead and balanced that acid-base reaction, we can solve this problem, right? We can say, stoichiometrically, what would be the mass of HCl if we started with 5.5 grams of magnesium hydroxide? Does everybody follow me? Right? Okay, cool. So, we talked about this in the last problem. For this one, what are the two numbers that you should be calculating before you even attempt to solve this problem? The molar mass of what? Magnesium hydroxide. Okay, the molar mass of magnesium hydroxide, and what do you get for that? I got 58.32 grams per mole, and the other thing, the molar mass of HCl, right? Because we have magnesium hydroxide, we've got to convert it to HCl. So, the molar mass of HCl that I got was 36.46 grams per mole. Now, if you're having trouble doing that, you're not going to get the right answer, of course. So, to figure out the mass of HCl, we have to do some stoichiometric calculation, okay? And the only given number that we're starting out with is this mass of magnesium hydroxide. So, we're going to have to use that to figure out what the molar mass of HCl is. So, I'm going to do it the way that I like to do it, and you know how I like to do it, very long and drawn out, okay? So, 5.50 grams, and I'm going to put magnesium hydroxide just so we don't get lost as we're going along, okay? Now, we don't want mass of magnesium hydroxide. So, we're going to have to convert that to moles first. Then go to moles of HCl, then convert that back to grams of HCl, okay? So, in order to do that, we want to get moles of magnesium hydroxide. So, what are we going to put at the bottom here? Down here. So, what's the number? How about that? 50. Yeah, very good. 58.32, okay? So, if you can do that, then you should be able to do the rest. 58.32 magnesium, grams of magnesium hydroxide, and then one mole of magnesium hydroxide. Notice I'm carrying that magnesium hydroxide through just as a placeholder. So, I know when I'm converting from moles of magnesium hydroxide to moles of hydrochloric acid, it's not just moles to moles, okay? So, when I do this, I can cancel there. Now, I've got moles of magnesium hydroxide, but that's not what I wanted. I want grams of HCl. So, in order to do that, I've got to get the moles of HCl. So, how many moles of HCl per mole of magnesium hydroxide react? Two, right? That's where we get that from the chemical reaction, okay? So, we say one mole of magnesium hydroxide reacts with two moles of HCl. And now we can cancel out our moles of magnesium hydroxide. Is everybody cool with what we've done? So, we're still not to grams of hydrochloric acid, but only one more step, right? So, we've got to use now the molar mass of hydrochloric acid. Everybody's probably on board with that, so I'm going to just multiply. What are we going to put down here? What number? What number? How many moles? One. Just one mole. One mole HCl. Well, how much does one mole of HCl weigh? 36.46 grams, okay? It's another way to think about it and make sure you're able to, what do you say, understand what we're actually doing mathematically, okay? Because this is actually, you can say this in words like I've been doing as we've been explaining. Okay, so hopefully you see now we cancel out our moles of HCl. And guess where we are, grams of HCl. Well, that's what we were looking for, right? So, good job. So, all we need to do now is get our calculator and let me show. So, what do I do? I take 5.50 and I'm going to first divide that by 58.32 and then multiply that number by 2 and then multiply that number by 36.46. So, when I calculate it, or what do you guys get? Yep, 6.88, what? Grams. Grams of HCl, okay? If you got that and didn't tell me, next time tell me while we're doing a video. So you can, so it sounds like everybody else. I might just want to use that. Any other questions? Any questions on this one? Starting out. Okay, good job guys.