 This is the last video, thank God, right, for this week's collection of videos. We're going to talk about something called a functional group. Basically, the way that I'm going to introduce a functional group is, as I mentioned in previous videos, there are zillions of different organic molecules out there in the universe. If you look at enough of them, sometimes what you will see on some of them are the same pattern of atoms found on many different kinds of molecules. If you put that particular pattern of atoms, let's say that I have maybe three carbons here and an oxygen and a hydrogen, maybe this is my pattern. I use this last bond to stick this pattern of atoms onto some other molecule. If I stick this pattern of atoms onto a molecule, maybe it gives that molecule a certain feature or a certain behavior. It doesn't matter what other molecule I stick this onto, as long as I stick this specific pattern onto any other molecule, it gives any of those molecules a specific feature. If I have a pattern of atoms that does that, that pattern of atoms is called a functional group because it's a group of atoms that gives a certain function to whatever molecule I stick that group of atoms onto. What I'm going to do in this video is I'm going to describe some functional groups, some patterns of atoms that you're going to have to be able to recognize under different situations and basically name those functional groups. What you're going to see is there are certain functional groups that have names that are identical to the names of certain things that we use in English, in common English. For example, alcohol is a functional group, but I'm sure you've heard of alcohol. You may have heard the word aromatic before, you may have heard the word polyester before. These are all functional groups in chemistry. A functional group is a group or a pattern of atoms that you see in organic molecules over and over again and no matter what kind of molecule you stick that pattern of atoms onto, it gives a certain feature to that molecule. This is a molecule, it's a very simple molecule that has what's called an alkene functional group. That's an E there. This is the simplest molecule with an alkene functional group. If you have a molecule with two carbon atoms double bonded to each other, then your molecule has an alkene functional group. Like I said, this is the simplest one that has an alkene because there isn't much else there except for some hydrogens. We're going to skip this one for the moment. This molecule is the simplest molecule with what's called an alkyne functional group. That's a Y there. If you have a molecule with two carbon atoms triple bonded to each other like we have here, then you say that your molecule has an alkyne functional group. Molecules that have this functional group, they have a tendency to have certain odors or certain smells, so you can think of alkenes as maybe having that function. They give certain things, certain odors. That's not always true, but a lot of times it is true. I have no idea what functions alkynes have that I could tell you that sounds reasonable, so we're going to skip that one. This one over here, if you have, you have to have all of these features. Six carbons wrapped around, so one, two, three, four, five, six. You have to have that, and you have to have alternating double and single bonds. They have to alternate, and if they go double, single, double, single, double, single, if you have both of those things, it's got to be six wrapped around, and you have to have alternating double and single bonds, then you say that your molecule has an aromatic functional group. This is the simplest molecule with an aromatic functional group because there isn't much else there other than what I just described and some hydrogens. If you've ever heard the word aromatic before, that means something that has a certain odor. So around 150 years ago, maybe a little bit less than that, when they were making molecules that had this particular pattern in them, all of the molecules that they made had certain smells. So they thought, well, this pattern must give molecules certain smells, so they called it an aromatic functional group. It turns out that they were wrong. There are many molecules that have this pattern that don't have any smell at all, but the name kind of stuck. So I expect if I show you this kind of molecule, if I show you a molecule with this pattern in it, you should be able to say, oh, it has an aromatic functional group. If I show you a molecule that has carbon-carbon double bonds like that, you should say, oh, my molecule has an alkene functional group. If I show you a molecule that has a carbon-carbon triple bond, you should be able to say, oh, it has an alkyne functional group. If it helps you remember alkyne and alkyne, you should remember that we've already talked about alkyne molecules. They have all single bonds between carbons. Alkenes, we know they have to have at least one carbon-carbon double bond, and alkynes, they have to have at least one carbon-carbon triple bond. And if you notice, we go single, double, triple, and that goes alphabetically, A, E, Y. That's probably not a coincidence. I figure somebody named them that way, but there you go. Those three patterns I expect you to be able to recognize. So for example, in an exam, maybe you see something like this. I show you this molecule, and I say, what functional groups does it have? Well, it doesn't have any alkyne functional groups. Bet your ass it does. There's a couple right there. Does it have any alkyne functional groups? No. There's no carbon-carbon triple bonds in that molecule. Does it have an aromatic functional group? It does. There it is. I'm going to ask you a couple of questions before we go on. Does that molecule have an aromatic functional group? This one right here. You can pause the video and think about that. The answer is no. It does have alternating single and double bonds. The carbons wrap around in a circle, but it does not have six. This one has eight carbons. What about this one? Does this molecule have an aromatic functional group? The answer is no, because it does not have alternating single and double bonds. It does have six carbons wrapped around in a circle, but that means this one is called cyclohexane. This one is not cyclohexane because it has those double bonds. It has a different name. More functional groups that you're going to need to know. If you have a carbon, there is a carbon here. The carbon is single bonded to an oxygen, and the oxygen is bonded to a hydrogen. This O and this H are called an alcohol functional group. Now, if you look at this, how many carbons does this particular molecule with an alcohol functional group have? Well, it has two. And if you remember the alkyne molecule, this is related. It's similar to an alkyne molecule called ethane, because ethane is the alkyne with two carbon atoms. But this ain't ethane. It's ethane with an alcohol. So guess what it's called? It's called, can I spell? Apparently I can't spell. It's called ethanol, and that's why it's called ethanol, because it's kind of like ethane with an alcohol. This is the booze that gets you drunk. This is also another drawing of ethanol, which is just the expanded structure. There's my two carbons. There's my alcohol functional group. What do you think the name of this molecule is? It has an alcohol functional group. It has one carbon. You can pause the video and think about that on pausing. One carbon is related to methane, but this ain't methane. It's methane with an alcohol group. So it is called methanol. This is the booze that if you drink it, it will make you go blind and possibly kill you. So please don't do that. So you should be able to recognize a molecule with an alcohol functional group. This is, if you have a carbon atom and it is single bonded to a sulfur, and the sulfur is bonded to a hydrogen, this sucker right here is called a thyle functional group. It's kind of like an alcohol. In fact, it's very much like an alcohol, except instead of an oxygen, there's a sulfur in the place of the oxygen. So this is called a thyle functional group. These kinds of molecules with thyle, they usually have pretty nasty smells, like rotten eggs, things like that. So if I showed you this molecule and I said what functional groups does it have, you would say, oh, it has a thyle, because there's a carbon here, single bonded to an S and H, and that's a thyle, and it also has an aromatic functional group. Isn't this exciting? You get to do this, huh? All right, more functional groups, and we're almost at the end. You don't need to know aldehyde. I'm going to skip that one. I'm going to skip ketone as well. This one you should know. There's a carbon here at that corner. If you have a carbon, double bonded to an oxygen, and the same carbon is single bonded to an OH. This whole pattern here is called a carboxylic acid. And for whatever reason, the students never seem to be able to practice it in the mirror or something. This is the pattern that you see. It doesn't matter whatever else is attached there. You can have Kanye West stuck over here, for all I care. If it's this stuck on Kanye West, then it's Kanye with a carboxylic acid. I don't even know if he's cool anymore, so if there's somebody cool now or cooler than that, you can put that person's name in. If you have a carbon, double bonded to an O, single bonded to an O, and then that O is single bonded to another carbon, this particular pattern is called an ester functional group. If you have ever heard the word polyester, like polyester, suit, or something like that, that suit is made of molecules that have this particular pattern over and over again. You should know this one. You should definitely know a mean. If you have a carbon, and it is single bonded to a nitrogen, this nitrogen here is called and is part of an amine functional group. If you have heard of molecules called amino acids, amino acid molecules always have an amine functional group, and they always have a carboxylic acid functional group, and that's why they're called amino acids. Last one that I want you to know, if you have this carbon double bonded to an O and single bonded to a nitrogen, this particular pattern that I'm putting inside of a box is called an amide, an amide functional group. Sometimes people call it amide or amide. There's probably 10 million ways of pronouncing it, but that's the pattern. If you notice, again, this is not really a coincidence, the amide functional group, this one right here, looks like a cross between the carboxylic acid and the amine. In other words, it has this little bit that looks like part of the carboxylic acid, and it has this little bit that looks like part of the amine, and that is not a coincidence. A lot of times amide functional groups are made using a special chemical reaction that kind of combines these two things, but we will not talk about that until the very last lecture. You lucky people. Two more things before we go. First thing is that I showed you this molecule in one of the very first videos, and I said this is not butane, even though its formula is C4H10, and I said this one gets its own special name. Well, we might as well spend a minute figuring out what the name of this molecule is. And same rules apply. We find the longest chain of carbons, that's one, two, three. I got three carbons in a row, that's the most that I have in a row. Three carbons is kind of like propane, so the back end of that molecule's name is going to be propane. This is the side street. This part here is the main road. This part here is the side street. So let me get rid of some of the noise here. There. So there's our main road. This is our side street. How many carbons in this side street? Well, there's one. So it's kind of like methane, so it's going to be called methyl. So the back end of this molecule's name is going to be called methyl propane. And here's our side street. We have to number the carbons on the main road, so I'm going to number them one, two, three. It doesn't really matter which order I number them in, the side street is on number two either way. So that beast there is called two methyl propane. So this thing here, that is called butane, and this thing here is called two methyl propane. They both have the same formula, C4H10, but they have their own special names because they are isomers of each other, so isomers get their own names. The last thing I want to talk about is this molecule here. I've shown you this molecule at the beginning of this lecture. The majority of you would have looked at this and said it was from Mars, right? It just looks like some crazy thing. But now you can look at this and you can see a lot of information. There are carbons all over the place, right? Carbons here. There are hydrogens all over the place. There's a hydrogen there, hydrogen there. You can figure out where the hydrogens are. You can figure out where the carbons are. You can see double bonds. There are many different functional groups that we've already talked about here. You should spend a minute, you pause the video, and try to find them. I'll tell you, there are alcohol functional groups. There's a carboxylic acid functional group. There's an amide functional group. There's an amine. There is an aromatic, at least one aromatic, and some alkenes, I think. So, on pausing the video, here's a couple of alcohols. These bonds that look a little bit weird, we will talk about them later in the course, but they are just covalent bonds. So, these are alcohols. Carboxylic acid. Boom, right there. Amide functional group, where are you? Here it is. Upside down, but there it is. Carbon double bonded to an O, single bonded to a nitrogen, that is an amide. Amine functional group, here's some alkenes. Aromatic, aromatic, aromatic. You might not necessarily be able to pick them out now, but you should be able to pick out those kinds of functional groups once you have those patterns committed to memory. And last but not least, this is the chemical structure for a medicine called Lipitor. Lipitor is used to treat high cholesterol levels, which is associated with cardiovascular problems, but this is Lipitor. This is the IUPAC name for Lipitor. So, if you wanted to give the formal, proper name for this molecule here, it is this big ugliness here. There are not too many people who know the rules well enough for IUPAC naming to give the proper name for Lipitor. There are computers that know the rules much better than any human does, and they usually do this kind of work, but this is just to show you that the names can get really complicated and the rules can get really complicated. But you should be able to look at this thing now and be able to see a lot of stuff. Carbons all over the place, hydrogens that aren't drawn, you should be able to find functional groups like alcohols, things like that. That's the end of this video. Next week there will be more organic chemistry, and I think the week after that, maybe some more organic chemistry and then, I don't know what. But, see you around.