They appear to be 180 degrees away from each other. What I have is a large group in the back and a large group in the front. Let's go down and see if that's what I drew. And what's the bond angle, the dihedral angle, by the way, for anti? 180.

What is the most stable conformation? That's going to be anti. So we're looking for the most stable conformation. What does energetically favorable mean? Well, I'll just tell you right now, if you see something that says favorable, that's a good thing. Well, he specifically said draw the most energetically favorable. I have to go up here and see what he said. Then determine which dihedral angle would correspond.

So I have to make sure that this is the exact one that he wants. The only thing is that I don't know if it's the energy state that the professor was asking for because the professor could ask for any energy state. So now that we've drawn that Newman projection, that is a valid Newman projection. And your professor might use those more than he uses the actual letters.

There's abbreviations for a bunch of these different ones. Does that make sense? Another way to write that would have been to write Et, which stands for ethyl.ДЄnother way to write CH3 would be to write Me, which stands for methyl. So that would be what you could just write as CH2, CH3. And then what else does it have? Well, it has a two-carbon chain coming off of it. So the blue one seems to have two H's, H and H. The blue one, imagine that it's kind of peeking out from behind the red one, so the blue one is going to be a circle behind and then I'm going to draw the three groups that the blue one is on, that the blue one has Well, it seems to be attached to an H on the top, an H on the top and then a CH3 at the bottom. It doesn't matter as long as the other one is consistent.Д«asically, what I would say is then what are the three things that that red carbon is attached to. You can start with it with a point up or you can start with a point down. You can draw your little triangle thing, whatever that's called, however you want. And I would draw that it has three things coming off of it. So my red carbon I would just draw with a little dot. So I'm going to say that for example, the front one is my red carbon and the back one is my blue carbon. Now what we're going to do is we're going to draw a front carbon with three groups on the front and then a back carbon with three groups on the back like I was doing when I told you guys about the way Newman projection works. You don't need to necessarily write the numbers as long as you just know what bond it is. But I'll just go ahead and use this other one. Now, it could have also been, just letting you know, it could have also been this one because if you were counting your 1 from over here, then this would have been your 2 and your 3. Just like when I was talking to you about conformers, that you could have sigma with s-cis or s-trans, he's picking out which sigma you're going to use, which sigma bond you're going to rotate and that's going to be this sigma bond right there because basically what you want to do is you want to go from the second carbon to the third carbon. That's your professor telling you that he wants you to focus on a certain bond that's going to rotate. What is the bond of interest? What? It's this, C2-C3. The second thing I'm going to do is I'm going to highlight the bond of interest. Newman Projections to Bondline Structures Calculating Energy Difference Between Chair Conformations

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