 Okay, so let's do this problem, it says, draw the least stable conformation of pentane using a Newman projection to view along the C2C3 bond, okay? So the least stable conformation of pentane. So we, first thing we want to do is draw pentane, what it looks like in bottom line form. And then it says C2C3, right? So remember whenever we're doing that, we're counting from one of the terminal ends, okay? So in this case, this would be carbon one, so we'll call this carbon two and carbon three, okay? So remember, how to draw a Newman projection, does that make sense? Are we cool with that one? Yeah, okay, good. How to draw a Newman projection, right? We're going to draw a circle and then in the middle of that circle, dot. So like a big I or something. And eventually it's going to look kind of like spokes on a wheel. Okay, so this is where we're starting, okay? So now let's draw, I like to draw this terminal methyl group first on C2. So I'll just draw it down like that. So I will label that as methyl. So what we have here now is this is carbon one, this is carbon two, I'll label that as such, okay? And then this big circle around it is carbon three, okay? So you have to just pretend that they're the same size, okay? Or we draw it like that because if they were the same size, we wouldn't be able to see the back carbon. Okay, so now, so at this point in time, I'm actually just going to draw how we have it here, okay? And then I'll change it in the Newman projection, okay? So now we have this one, two, this ethyl group coming off and I'm going to draw that somewhere, okay? So CH2, CH13. So now I'm just going to draw my hydrogens. And remember, they're implied, of course, in the bond line structure. So we have something like that, okay? So is everybody okay with the carbon two and three? Can I erase those little numbers? Is that all right, yeah, okay, well, I like the responses, like you're getting it, though, right? That's good, that's awesome, I'm really proud of you, okay? So what we have, stop making me laugh, okay? So what we have here is that the big groups, right, an ethyl group and a methyl group in relation to all the other groups on each of those carbon, so to the big groups, right? So in other words, an ethyl group is bigger than a hydrogen and bigger than a hydrogen, right? A methyl group is bigger than a hydrogen and a hydrogen. So when we have the two big groups, the two big alkyl groups on opposite sides, like 180 degrees away from each other, we call that anti-periplanar, okay? So we have this in an anti-periplanar arrangement, periplanar arrangement, that's the most stable conformation, okay, so that's the most stable, okay? So that's what we see here in the bond line form, okay? Kind of like what we call that Charlie Brown stuff, right? So what we want to do is make this the least stable, okay? So remember to get to the least stable, we have to get the two big groups, synperiplanar, to each other, okay, or on top of each other, zero degrees away from each other, okay? We call that synperiplanar. So what we're going to do is rotate this around, so can I erase this arrow here that I have? Yes. So it won't be, thank you, so it won't be confusing to us. Okay, so what I'll do is I'll just rotate carbon 2, the little dot in front, and I'll rotate it around to make it eclipsing, the methyl group eclipsing the ethyl group, okay, so everybody understands what I'm talking about. So I'm just going to kind of rotate this that way, then again, then again, okay? So I'm going to do that kind of three rotation, that somebody who has the model kit out there will contain for me, okay, real quick. Let's see if we can do it before I finish the video. Somebody, both of you, everybody who has a model kit don't pick it, how about that one, okay? So when we do this, of course, this conformer, we call these different conformers, right? They're the same molecule in different conformations. This conformer is more stable than the other conformer, so if we want to actually write our equilibrium arrows, we can do it like this, it's going to be something like that, it's going to be favoring that way until we draw the other one. Circle, and remember, we're recording this though. You can always watch this later, it would be cool if we can get that contain structure done with all of its hydrogens, so we can all see what's going on. So we just moved carbon two, remember, okay? Not carbon three, so that's going to look exactly the same. So I'm going to rewrite what carbon three looks like. Is everybody okay with that? What have you done there? So do you see, it's all the same. The back carbon is all the same. So now, we can't really draw, just like we couldn't draw carbon two and carbon three as equivalent sizes, I need all the hydrogens on there too. I know you got to go fast, okay? So just like we couldn't draw carbon two and carbon three on the, this is equivalent sizes, we can't really show the eclipsing exactly equivalent, okay? So we're going to have to kind of tweak our eyes a little bit and kind of just draw the methyl group to pretend like, you know, it's kind of eclipsing, but we know that it's actually zero degrees, okay, from each other, okay? Does everybody understand what I'm saying? You get that? So there's the other hydrogen and those are eclipsing too, there's the other hydrogen there, okay? So because we've got the two groups eclipsing each other with an eclipse form, this one's called the synpary planar, why? Because the two big groups are zero degrees away from each other, do we have it? Wonderful thing. So what we've done here, he almost got it, that's okay though. Okay, so what we've done here is if we, so is everybody okay with what we have here? That's the answer to the problem, so the answer to this problem is right. That's the least stable conformation if we're looking down the C2, C3, okay? So the most stable, remember, is this or this, right? So we're looking at it like this. Do you see that painting like that, okay? So I'm just gonna take it from here and kind of get in front of the camera so we can really see it. Is everybody okay with that, okay? So we're looking down the C2, C3 here, right? So when we do that, Newman projection, remember I showed you with the bond line form was the most stable here. So do you see that, we're looking down the C2, C3, there's that methyl group on the bottom and the alpha group on the top, there. Okay, do you see that, okay, wonderful. So that's the most stable conformation because the two big groups are so far away from each other, 180 degrees away from each other, we call it anti-pary planar. So in order to make them unfavorable, we're going to eclipse some of the two big groups. So we're gonna have to turn it once and then turn it again and then turn it again. So three times, 60 degrees each time, right? Okay, so now we've got the methyl group and the ethyl group eclipsing each other. We call that synpary planar and hopefully you can see how much, you know, more sterically hindered or sterically obstructed those two alkyl groups off, okay? So we can actually, almost, okay? So you can see it from this way and you can see it from this way, okay? Different conformers. Any questions? If we were gonna draw the long line of this, we would draw it like this. Any other questions on it? Yeah? Yeah, you could have used the band one as well, yeah. So that would have, you know, instead of taking the methyl group and moving it this way, you would have taken the methyl group and moved it that way, but it would just be this flipped over, okay? But yeah, you can equally do that, okay? Any other questions? That's a good question. But Sharon, was the bold compromise agreed? No, this is not cyclohexane, okay? This is something totally different, okay? Let's keep the questions on topic, okay? Any other questions on this one? Okay, wonderful.