 Okay, so let's try another one of these types of problems. It says, how many degrees of unsaturation are there in valium or diazepam? And then it gives the molecular formula C16 H13 into OCO. Okay? So, when we look at the molecular formula like this, how do we start going about figuring out the number of units of unsaturation? We look at the C H. The C's and H's, right? And what do we do with those? Do we do anything with them? No. So what do we do with these other guys? We have to look at the periodic table. And what does that tell us? Tell us how many hydrogens subtract from them. Subtract or add or whatever, right? Okay. So what we're going to have to do is, when we look at the periodic table, what does it tell us about hydrogens? What do we have to do with the other hydrogens? Subtract. A hydrogen, right? So if we had two hydrogens, how many would we subtract? Subtract, two hydrogens. So let's just put for our own sake, just minus two hydrogens there, and then cancel that. Okay? And then what happens when we have an oxygen? We don't do that. Okay? So we cancel that out. And then if we have a halogen, like a corn, we add a hydrogen. So let's cancel that and push a one hydrogen like that. Okay? So negative two plus one, right? That's minus one hydrogen, right? So we'll bring this down. So C16 H13 minus one hydrogen is what? 12 hydrogens. 12 hydrogens, right? So H12 like that. Okay? So how do we go from here to determine the number of units of unsaturation? Use formula. The alkane formula, right? Okay. So what is that formula? Cn. Okay. So let's write it down again. Cn. H2n plus two. Okay. 2n plus two. Okay. So you got that one, right? Does this equate to that formula? So if we put in 16, does it give you 12? No. Right? So we know that this has some units of unsaturation of some degrees, okay? So what do we got to do? We got to put that 16 more than this, right? Yeah. So when we do that, we get C16 H1. Cn plus two. So what is that? 34. 34, right? Because 16 times two is 32, plus two is 34, right? Okay. So what do we do now? That's the other one, right? Because we call the base, okay? So we'll subtract that. So the C16 H12 from that. Okay. That's all right. What do we get from that? 22. Right. So H22. Okay. And how many units of unsaturation does that equate to? Divide by two. So we get 11. Yeah. So if we divide that by two, we get 11. So it's 11 degrees. Any questions on that? Pretty straightforward now, right? We got it pretty down. Okay, good.