 Okay, this drill is very similar to another drill, a couple of videos back, but it's maybe a tiny bit more complicated. I want to talk about this molecule here. This is called sulfuric acid. You don't need to know that. But the formula for sulfuric acid is two hydrogens, one sulfur, four oxygens. And I've kind of shown that in cartoon fashion here. So two red circles for the hydrogens. One orange circle for the sulfur and four blue circles. For the oxygens, they're all stuck to each other. It doesn't really matter how they're stuck. All you want to think about is this whole thing, this little egg here is one sulfuric acid molecule. If you crack it open, you're going to get two hydrogens, one sulfur, four oxygens. And again, this is similar to the car question. So that's why there's a ridiculous picture of a robot car here. It's similar to the Toyota Corolla question and how many wheels does the Corolla have. This drill is similar to that. So let's go. I have one mole of sulfuric acid molecules. How many molecules do I have? Well, 6.02 times 10 to the 23 sulfuric acid molecules. How many hydrogen atoms do I have? If I have one mole of sulfuric acid molecules. So these two questions are related. If I have one mole of sulfuric acid molecules, how many hydrogen atoms do I have? You can pause, try to answer that. If you unpause, you should realize that inside of this egg, inside of one molecule, there are always twice as many hydrogens. So if I have this many sulfuric acids, I have to have twice as many hydrogens. And that's 2 times 6.02 times 10 to the 23, which is 1.204 times 10 to the 24 H atoms. And again, this is similar to asking how many wheels. If you have 10 cars, how many wheels do you have? Well, there's four wheels on a car, so I must have 40 wheels. If I have this many sulfuric acids, how many hydrogens do I have? Well, there's two hydrogens inside of every one sulfuric acid, so I have to have twice as much. How many sulfur atoms do I have? You can pause and answer that. But again, it's going to be pretty straightforward. If you crack open a sulfuric acid molecule, there's one sulfur inside of every sulfuric acid molecule. So it's going to be 1 times 6.02 times 10 to the 23 sulfur atoms. But, you know, 1 times any number is just going to be the original number. So it's going to be 6.02 times 10 to the 23 sulfur atoms. And then last but not least, how many oxygen atoms do I have? Well, every time you crack open this molecule, four oxygens come tumbling out. So if I have this many sulfuric acid molecules, I have to have 4 times that many times 10 to the 23 oxygen atoms. And I don't know what 4 times 6.02 times 10 to the 24 is. It's 2.408 times 10. So 4 times 6.02 times 10, that's a 10, to the 23 is equal to 2.408 times 10 to the 24 oxygens. So here are the answers to those three questions. You should be able to answer questions like that as well. So again, very short drill. I think the new topic is coming up next. I've been promising it and promising it, and I know everybody's dying to hear about it. So it's coming up next up on whatever the heck this course is, Chemistry 101.