 Okay, in this video, hopefully it will be relatively brief. I want to talk about molecules with aromatic functional groups. If you remember from last week, I said that a molecule with an aromatic functional group had to have six carbons in a ring, and it has to be six, and it has to be a ring, and the other feature that it has to have is you have to have alternating double and single bonds like that. This is the simplest molecule that has an aromatic functional group. It's called benzene. You don't need to know that. This is a component of gasoline. One thing that I'm going to point out, and usually I give an explanation for why this is, but I'm not going to talk about that. You can see the double bonds and the single bonds in this molecule. People who have studied these molecules very carefully have noticed that you can think of the double bonds as constantly flipping around. The double bond is here, but every split second, it moves over there. This one moves over there, and that one moves over there. This is also benzene, even though the double bonds have moved positions. You can think of those double bonds as essentially racing around inside of the ring. Because of that, because of the double bonds and the single bonds are not really stuck in place, there is another way to draw a molecule with an aromatic functional group. That is to draw the ring, this little collection there, but instead of drawing the individual single and double bonds, people just draw a circle in the middle. That circle is supposed to say, look, those double and single bonds are not really fixed in place. They're racing around inside. If you see this, that also means aromatic functional group. That is basically all I want to talk about in this video. The process of having the double bonds and single bonds flip around like that in chemistry, it's called a resonance. If you ever take a full course in organic chemistry, you spend an awful lot of time talking about resonance, but you do not need to know, you don't even need to know this word. It's just there on the slide for reasons that I can't remember. You can see aromatic compounds everywhere. This is aspirin. Aspirin has an aromatic functional group. This is ibuprofen. You can see the aromatic functional group. They can be drawn like this or they can be drawn like that, and I want you to realize that you could see it in either way. That's the end of this video.