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Video transcript

a functional group is a group of atoms that has a predictable chemical behavior and there are many functional groups in organic chemistry and I'm going to cover some of the more common ones the ones you'd have to know for your class so we start with an alkene and now Keene has a carbon-carbon double bond in it so here is a carbon-carbon double bond are refers to the rest of the compound or the remainder of the compound and normally we're talking about carbons and hydrogen's let's look at an example of an alkene so over here on the right we can see that this molecule contains a carbon-carbon double bond so this is an an alkene so how do we name this well if we had a four carbon alkane let me go ahead and write out a four carbon alkane here so one two three four we already know we should call that two butane so this one should be called butane and since we have a four carbon alkane we're going to lose our ending here a and E and we're going to add on a and E the ending for an alkene so the name of this molecule is butene let me go ahead and write that out here so this is butene and if we number this molecule we start with a double bond and we give this carbon right here a number one and then we have a number two right here and number three for this carbon and number four for this carbon our double bond starts at carbon one so we put a 1 in front here and we call this one butene let's look another example of an alkene if we drew out a ring like this we already know this is called cyclohexane if we put in a double bond now it's cyclohexene and you can see this has a carbon-carbon double bond and so does this molecule so they both contain an alkene functional group and therefore both these molecules will undergo the same types of reactions they have predictable chemical behaviors and that's the usefulness of grouping functional groups of identifying functional groups on molecules our next example of a functional group is an alkyne so this time it's a carbon-carbon triple bond so here you can see the carbon-carbon triple bond in an L kind so if you look at the right here's our example and we number our carbons we could call this carbon one this is carbon two carbon three and carbon four so you're drawing an alkyne we know that this is linear at this portion of the molecule this bond angle is linear so that's why it's drawn in a straight line so four carbons so we would use Butte and we have a Y n e ending for an alkyne so this is butan let me write out butane here and our triple bond starts at carbon two so here is where our triple bond starts so we could write 2 butene for the IU pack name next we're looking at an arene also called an aromatic ring and you're looking for this you're looking for a six carbon ring and you have alternating single double bonds so total of three double bonds now just because it has double bonds this doesn't mean that it's going to be an alkene actually airings react in different ways from alkenes and that's why this is a separate functional group so on the right here's an example of an airing with or an aromatic ring and this right here this portion of the molecule would be of benzene so let's write out that so benzene is a very famous organic chemistry molecule now we have a methyl group coming off of our benzene ring so one name for this would be methyl benzene that's not the name you would usually see normally you'll hear this molecule called toluene so it's so common that toluene is used most often so toluene is an example of an arene it contains an arene functional group and so toluene would react in similar ways to benzene all right let's look at our next functional group here this is an alkyl halide so halide refers to a halogen so over here on the right we have our halogen so X could be a halogen like chlorine or bromine and our will be our alkyl group for the example on the right let me get a little more more room down here our halogen is chlorine and our alkyl group here would be an ethyl group we have a ch2 and a ch3 so one possible name for this molecule would be ethyl chloride you could also call this something like chloro ethane alright next functional group is an alcohol so an alcohol has an O H and O H right here then are for the rest of the molecule as an example here's an OHA or a hydroxyl group and then we have a ch2 and a ch3 so we have two carbons in this molecule we know two carbons is F and for the full name this would be ethanol so a very famous molecule obviously so this is ethanol next we have an ether so an ether has an oxygen with an R group on either side so I'm sorry for the bad joke but if it helps you remember that you have an R group on either side of your oxygen it's worth putting in a bad joke into this video so now these R groups could be the same R groups or they could be different R groups for the example on the right we have our groups that happen to be the same so here's our oxygen and here's an R group and here's our group both of those R groups are ethyl groups so we call this diethyl ether so diethyl ether is the most famous either it's so famous that usually it's just referred to as ether but diethyl ether would be one way to name this molecule next we're going to look at a thigh all so a thigh all is similar to an alcohol instead of an O H though we have an SH so we have sulfur instead of an oxygen so for the example of a thigh over here on the right we have an SH here then we have an ethyl group so one name for this would be ethane thigh also I'm going to write this out here so ethane thigh all is one possible name for this molecule next we have a sulfide so a sulfide is similar to an ether and reformed ether we had our O R for a sulfide we have our s R so it's completely analogous to an ether so on the right here's our sulfur and again we have two ethyl groups so you can call this diethyl sulfide so let me write that out here so this is dye ethyl sulfide and finally for this video one more one more functional groups so this is an amine so for this amine we have nitrogen and then we have three R groups attached to nitrogen or you could be talking about hydrogen's here all right so any of these could be hydrogen's as well and so on the right is example of an amine we have a nitrogen with a lone pair of electrons this one has two ethyl groups and one of our one of our groups here is a hydrogen so one name for this is diethyl amine so let me write out that one so you could call this dye ethyl amine alright so we'll look at more functional groups in the next video