This is the answer to Chapter thirteen. Problem number two from the Smith Organic Chemistry Textbook on this problem. Eyes giving us three ions from three mass spectrometry experiments on DH asking us to rights impossible formulas for each ion. And so, essentially, what you want to do is just remember thie atomic weight of each different element on DH. See what kind of combinations you come up with. So for Ah, for an ion of seventy two. Easiest answer is C five h twelve on I've drawn the math out down here. Carbon weighs twelve. There's five of them. Hydrogen weighs one. There's twelve of them. S O sixty plus twelve is going to give you seventy two. Alternatively, you could include an oxygen. Remember, oxygen weighs sixteen. So four carbons in twelve apiece. Eight hydrogen is at one apiece on one oxygen at sixteen on. That also adds up to seventy two. So the answer to the next the next I on one hundred is pretty much, you know, exactly the same. You just find combinations that will add up to one hundred. And so again, the simplest one just carbon and hydrogen is going to be eight carbons. A twelve apiece and four Hodgins that want a piece again? If you wanted to include an oxygen, Um, you know, just as it's drawn out here, see six h twelve o. If you do the math that will add up to one hundred for you on DH, then I do just want oh, focus on the third part of this problem. Just a little bit eso We're asked to find formulas. Basically, that add up to seventy three. And what I was always taught was when you're looking at mass spectrometry problems, if you haven't a Nayan with an odd number. So in this case seventy three, you should immediately think that nitrogen is present. And so the two answers that I've drawn here both contain nice regions. S O nitrogen weighs fourteen, but what it's actually doing is forcing the hydrogen is to assume odd numbers. And that's how you get your odd number. And that's how you get to your seventy three. Because remember carbons or twelve oxygen's or sixteen nitrogen czar fourteen so you can never add to even numbers together or however many even numbers together and yet not number. But when you include a nitrogen. It's going tio force the hydrogen Sze to be an odd number. And that's how you get your ID number. And so again, I've drawn the math for each of these out in green. Uh, and that is the answer to Chapter thirteen. Problem number two.