AS LEVEL ORGANIC CHEMISTRY NOMENCLATURE OF ORGANIC COMPOUNDS

hi everyone welcome to eagles edgy concepts a platform that provides you with quality education science and mathematics starting from secondary level all the way up to a levels if you are visiting this channel for the first time don't forget to click on the subscribe button so that you can have access to more content in this lesson we're going to deal with our a.s level and chemistry the topic that we're looking at is a nomenclature of organic compounds so let's first of all just talk about the naming of organic compounds so many organic compounds have got common names that are derived from latin or frequent that indicate uh one of their natural sources so depending on where it comes from they can come up with a name there and that one is what we call the common name all right however most organic compounds can also be named by following some laid down rules and these rules are called systematic or substitutive names so the names that you come up by following a set of laid down rules is what we're going to call the systematic uh names or the substitutive names all right so the body that sets up these rules is called upak now the letters uh rather the acronym you park simply stands for international union of cure and applied chemistry all right let's dive right straight into the nomenclature so nomenclature is a standardized way of naming organic compounds nomenclature basically takes into account two things the first one is what we call a prefix now a prefix uh it simply shows the number of carbon atoms in an organic compound so usually if you remember your english feral a prefix is just referring to the first few letters of the main word okay so i think in a word we've got a prefix main route and a suffix so prefix is just a few the first few letters of a word so this one it's usually at the beginning of the name then it also puts into consideration what we call a suffix so the suffix this one shows the organic family of the organic compounds so it's usually at the end of the name of black for you to consider it more like a surname so a suffix just consider it as a surname and things will be simplified for you okay uh let's look at the prefixes that are found in organic chemistry so just look at the first 10 prefixes that are found in organic chemistry and when you are studying organic chemistry i think it needs your attention so it's not something that you just look at and believe you've understood it's something that actually you have to be looking at from time to time practice then you'll be okay with it so the first 10 prefixes in organic chemistry and this form the foundation upon which the other organic compounds are named these are the ones that are shown here so with the myth earth probe built spent hex hept octane and deck so in the order in which they are arranged meth it simply means one carbon atom if it simply means two carbon atoms and so on and so forth so the moment you see these letters anywhere meth just know that if there is one carbon atom there it doesn't matter what letters follow after but as long as at the beginning there is meth then you know that it's one carbon atom if it's f then you know that it's two carbon atoms if it's prop then it's three carbon atoms if it's hex then you know it's 6 carbon atoms and so on and so forth now just a quick example of some a few of the suffixes that are found in organic chemistry we are going to have uh a a-n-e this is a suffix for a family called alkenes we've got e-n-e this is a suffix for a family called alkynes and y-n-e this is a suffix rather a surname for a family called our kinds we also have the o-l and let's consider the o-l here so the o-l this is the suffix for a family called alcohols lastly we've got the uh so here i'm just going to consider oic this one is the suffix for what you call the carboxylic acids all right so let's quickly look at an example on how we can combine now coming up with a name of an organic compound is basically about generally it's about just joining the prefix and the suffix together and you come up with a name other specific details like considering the number the position of the substituents and so on and so forth will come in later on but in its simplest form when you are naming organic compounds simply get the prefix and the suffix put them together and you're okay good to go right so nomenclature of alkenes now alkenes are the simplest of all the homologous series in organic chemistry and as such they form the basis for naming other organic compounds okay stretching our cans let's look at the number of carbons there one two three four five so if we are to apply in the prefixes you know that this one is going to be uh this is this one is going to be um uh myth this one is going to be f this one is going to be crop this one is going to be beaut this one is going to be helped you should bear that in mind now these molecular formulas you know by now that molecular formulas they come from the general formula now if you remember very well from the previous video we looked at the general formula for uh this family and we discovered that it was as cn h2n uh plus two okay so it was plus two this was the general formula now here since it's number one so we are just going to put a one here and the one here so this one will be c1 h then two times one is two so two plus two that is four so c1 then h4 so one we usually ignore it so this is where the ch4 is coming from you can pause the video and just practice also with two three four and five and see how you're going to come up with these molecular formulas because if you're doing for two then you are going to put a 2 there then you are also going to put a 2 there so this becomes c 2 then 2 times 2 that is 4 4 plus 2 that is 6 that is where this one is coming from pause and practice all right so number of carbons we've got the molecular formula there then we also have the prefix remember prefix meth means one f means two prop means three but means four bent means uh five okay so then also because we are looking at the alkenes so generally we are saying the suffix for all alkenes it doesn't matter the number of carbons is simply a and e so that is our a and e then finally now if you want to name these alkenes here you're just going to get prefix plus suffix so meth plus a and e gives you methane f plus a and e gives you uh ethane prop propane but butane paint content as shown here so it is as simple as that let's look at some substituted alkenes meaning other groups have come in so for substituted alkenes if there are any side chains or functional groups present then these groups are indicated by numbering the carbon atoms in the longest chain starting at the end all right let's try to put more sense into this thing so we are saying the hydrocarbon side chain is shown in brackets in the structure formula for example this one and i want you to bear in mind that most of the side chains that you're going to deal with we're going to deal with the ch3 or the ch2ch3 so we have got the ch3 which is known as the methyl group and we've got the ch2ch3 which is known as the ether group so the main main chains side chains that we'll be dealing with is number one this group here which is called the methyl okay then we also have the one which which starts with ch2 then ch3 which will be called the ether group now the side chain is named by adding yl to the normal alkene stem so this type of group is called an alkyl group so when you add yl to the main alkene stem for example if you had methane you remove a n e and put y l then it becomes a methyl okay so that one will be called an alkyl group so important emitter ether and proper butyl and so on and so forth let's look at the first example here it says name the organic molecule below so like we said this one is branched as you can see we've got this straight ones here then we've got this one which is on its own which is branched so the first thing that you do is you have to identify the longest continuous chain of carbons so you can see we have the carbon the carbon and the carbon a carbon carbon so this is the longest so that one is going to give us what we call the parent name so the parent name just count remember if you count the number it uh you add the prefix and then you add the suffix then it gives you the name so here we have one two three four five six so we are counting the carbon atom so six six is x okay so when you add a n e as the family name then it's going to be x m okay so this is x okay then now how do you know is the correct number i always advise people number from both ends so the first the first thing we're going to do is we're going to number from here so numbering from here these are the blue or rather pepper numbers that are here so one two three four five six then you also number from the other end so starting from the other end one two three four five six as indicated by the green number here okay then which one is the correct number so you have to number such that at the branch okay so our emphasize at the branch layer at the branch okay at the branch it has the lower number you pick the one which is lower so for example if you start from here the branch will be on number three but if you start from uh my right here the branch will be on number four so the correct numbering is starting from the left because it gives the branch to number three so this is the correct so please number starting from both ends and then look at which one has got a lower number so what we want is to have the lowest possible at number so if you start from the left it should be three if you start from the right it should be four so start from the left so that you can get a three so you keep that three okay then you've also kept the parent uh name here so the parent name is derived from the longest chain so here we figured out that this one was what it was exam okay so exam so you keep the name exam okay then you also keep the branch the number of the branch where it is branching from then also you take note what name is given to the branch now remember this is ch3 now ch3 this one like we say these are the ones we'll be dealing with so this one will be known as the method so this is the metal group where you just do the prefix here the prefix is like this so you just need to add uh y error so this one becomes method then now since we have figured out this thing so the first thing like i said identify the parent chain which will provide the parent name then identify the lowest number possible by numbering on both sides and then you choose which one is lower and then you look at the name of the side chain itself so when numbering now you're going to start with the position where the chain is position the chain then the parent name so that is the order so position where the chain is branching from the name of the chain and then finally the parent chain so this one the name here that's why it is becoming three dash methyl hexane so the name will just be three methyl hexane all right you can pause the video read through the rules the longest chain of carbon atoms is six that's where we got the exam okay then the name of the chain is method then the position where it is branching from it should be the lower that's why you have to number from both ends so that you can easily compare okay uh we also have a situation where we have fully substituted alkenes now the previous example it was substituted quite right but it was just one but here we have a situation where it is poorly substituted now polysubstituted meaning it has got more than one branch okay one side more than one side chain so if there are more than one side chain of the same for example if you've got a lot of methyls maybe two three then we're going to use the numbers die for two try for three tetra for four and so on and so uh and so on and so forth okay now there is a situation where there is a situation where they they are fully substituted quite right but they are not the same so if such happens then you are just going to follow the alphabetical order all right also remember that the adjacent numbers have a comma between them the numbers are separated from words by a hyphen a hyphen simply what you saw like a dash okay then if the number if there is more than one type of alkyl side chains they are listed in alphabetical order so those are the simple rules that you need to follow once you follow that then you'll be able to come up with the systematic name of whatever compound that you be given let's look at the example okay all right so here we can identify the first thing let's identify the longest chain obviously it is this one here which is red so you count here these are then you number starting from both sides like i said you number starting from both sides so number one two three up to six so this is also an exam then you can also number from here one okay uh two number that's just number three then uh this one here will be four uh this one here is going to be five and then we're going to have six so you number from both sides then you have to choose now if you start from my right here if you start from the right uh the first chain is going to be three uh it's going to be on three then the other one is going to be on four then if you start from the left again we are going to have three and four so in this situation it doesn't matter where you start counting from because it is still giving you the same yt numbers three and four because there are two of them now if you check here so we have said this is the xn here so this is the hexane okay i'll just write h4 and then okay and also here i've checked xn because it has got single bonds and not double bonds so we have to bear that in mind as well all right so uh exam then the name of the chains here so this is a methyl group but we have this as the first methyl group here then we also have another methyl group then also we have another methyl group there so we have three of them okay we have three of them okay so since we have the three of them we can combine now this is since there are three of them we can say one is this is just three comma four so this is three comma four then try method okay try method let's look at this okay so this is three comma three now here this is three okay so when you start from here so here like i said because here there are two one two so the correct number in actual here comes to be these ones in green because on three here there are two but if you start from here on three there's just one so it's better you start from here whether it's two on three so this is three comma three meaning that on position three there are two of them so three comma three comma four try method exam i hope this is clear three comma three try method exam now like i said let me repeat this one you number on both ends then you discover that at three comma four they were branching so initially we said it can be the same but on the second thought when you check since on this position here there are two of them so it's better prioritized so that it becomes the third one so the correct number is starts from uh my left here okay so this becomes three comma three because on three there are two of them so three comma three and then here is one so three comma three comma four tri methyl so try meaning three and the parent here you say this exam so just join them together and you are done with the name so remember if they are poly substituted the commas they separate the numbers but these numbers and the the word is connected by a hyphen okay uh let's look at this other example you can do the numbering here you can number right now you are you can number this is one this is uh two this is uh three this is four this is five this is six now if you count this is one two three four five six seven also here this is uh one two three four five six so the longest continuous chain here is actually the one which has two quarter one which has got uh the six okay longest continuous chain not just any chain but longest continuously so it's for six so you can also number from here one uh two this is uh three four uh five there and this is six okay so you number both sides then let's look at the chain so we've got a chain here and the chain here so now when we start numbering from here we are going to have our first chain only two so the first chain will be on two then the second one will be on four but if we start numbering from here the right hand side the first chain is going to be on three then the second one on five so three and five are definitely higher than two and four so the correct numbering is to start from here so as a result we know that this method group is on two so this is two comma so this one will be two comma then the second one is one fourth so what you're going to do is on two we have a method so you're going to write two method okay two method then four ether are four so this one if you check it properly this is one two three so this is a propel okay so one two three from pro you just add y l it becomes proper okay let's look at the full name so remember the rules identify the longest continuous chain it gives the parent so the parent here we figured out it was actually a hexane so this is exam then also we've identified the correct numbering and also the names of the side chains when you put them together we are going to come up with this one so two method then four proper so it's stating as that on position two we have a method on position four we've got a proper so just like driving a vehicle if you're a driver you can take it forward you can also take it backwards you can reverse so from the name you can draw the structure from the structure you can come up with the name all right uh now like i said alkenes they just form the basis of uh naming okay but how about if we bring in the other other organic compounds into play okay so the same rules are just going to be modified are just going to be modified uh with respect to the functional groups that they have so most of the families of organic compounds their names are primarily derived from perkins other things such as functional groups or suffixes of different homologous series are put into consideration when deducing the names so the only thing that is going to be different is that is the suffix but the prefixes will be the same like we gave in the beginning of this lesson so the suffixes are going to be different because just like here on earth different families have got different synonyms with the pandas but monzas and all those other fun families same applies to organ chemistry okay so names derived in such a way like we said they are known as systematic white names okay so just a recap on the various functional groups that we have and those that are going to change the naming we've got the alkenes by now people should know that alkenes is just a carbon carbon double bond then we've got the alkynes which is the carbon uh this alkene is the carbon carbon single bond then the alkenes is the carbon carbon double bond then we've got the alkynes which is the carbon carbon triple bond we've got the benzene ring which can also be called a phenyl group we've got the alkyl halides which is the the bromide fluoride chloride iodide with the the thyroid group over the alcohol we've got the aldehyde with the ketone we've got the ester there with the carboxylic acid and the water amide so all these are supposed to be considered when you are naming these other organic compounds let's quickly look at an example in conclusion examples just six of them so for the first one what you have to do primarily so they said we should name these molecules here let's see how we can name them okay so number one the first thing that you have to do identify the longest continuous chain which has been done here in the red line so this is one two three four five six remember what we said when we are introducing in the other video about the the skeletal formulas so here at the carbon at the bending here is the carbon there's the carbon there's the carbon carbon and the carbon so that's why we are putting these numbers one two three four five six then you also look at the functional group so here we have this functional group here so this since there's a carbon here in the carbon this functional group is giving us this one here carbon what we are calling a carbon carbon double bond so carbon carbon double bond okay so this one is an alkene so you know that when you count this one one two three four five six so this one the name will be like hexing x in with e and e at the end e e at the end so xc so the parent name here is xc however you have to mention also these um the branches where are they branching from so here when numbering for alkenes you don't just number both sides but you also have to make sure that the double bond has got the lowest number possible so for example if we started from here it would be one two three four here this one will be five and this one will be six so now the double bond is the one that is supposed to have the lowest number possible it's not just about the branches also remember at the fire engine is the c and i remember there we said uh a carbon needs cell four so it's going to like that and like that so this together will form ch3 so this is h this is also h and this is also at h okay so this is ch3 ch3 also this one is ch3 so already we have three branches we have one two three then this one here this is two so it's on position two so the correct number in here is to start from the left because the double bond will be on two but if we started from the right the double bond is going to be on four so when it comes to our chains you follow the double bond the double bond is the one that is supposed to have the lowest position all right so having that said following the same rules we are going to say uh here what we have is two two comma so here two comma five comma five try method then dash two x sync okay so the name will be like this so two on two here there is a methyl then on five there are two method the two methods this one and this one so this one is a two comma five comma five then dash trimethyl then this two is trying to tell us that the double bond is on position two we originally like to say hexane but where is the double bond the double bond is on position two that's why we are putting this one as two it is just simply showing where the double bond is okay let's look at our second example here so the second example also we are going to identify our longest chain so if if now here we remember when numbering we have to start from where the double bond is so if we start from here one uh two three this one will become position one t to become position four so look at the double bond will be on position four so again if we start from here to one two three four again it will be on position four so we have to start from where the double bond is that would be our position one so one two three four five so as a result our longest chain then becomes what our five so this one will be 18 okay with e and e hep 10 18 so this is 18 now is there any other branch no so here uh if if we start from here then the whole lot of this one here is going to be a branch so this is ch2 ch2 ch3 so that is a proper as well so as a result we are going to have this so here on one two this this group here just counted this is a carbon here this is a carbon and this is a carbon so since there are three from prop you put yl it becomes proper so and it is attached on carbon two so that's why i say two proper then the double bond is on position one that's why we are putting one painting all right example number three here also you start from where now here you first identify uh you identify the functional group also so the functional group here it is telling us this is a c or here okay so this is a c o so meaning on this carbon here if if you have a carbon a double bond and something else here like oxygen or any other thing then this one is called a carbonyl carbon so always when you're numbering you start from a carbonyl t carbon so carbonyl carbon this is one two three so three that is uh prop okay that is drop okay now because of this functional group here it is an audi hybrid okay audi so this one is going to just be propane okay propane our dehydrator so our derivative is just t c h o so if we have to simplify the functional group is c uh h so this is how you know and how the height is ch they need before where is the order oh it's here the c is here then here if you extend this one we're going to have an edge remember in the other video we're introducing the same a carbonyl four so there's a carbon here then one two three and four so this is where the h is coming from so ch4 and aldehyde so if it's an aldehyde or any other higher function group you have to consider starting to count from the carbonyl carbon okay so the carbonyl carbon is the carbon that is double bonded to another atom carbonyl carbon is a carbon that is double bonded to another atom all right this other one here also here as you can see by the functional group here we know that it's an hour dehydrate so because it's an aldehyde we're going to start counting from the carbonyl carbon so the carbonyl carbon here which is number one two three four so on three here we've got a methyl group okay a methyl uh methyl group so this one we're going to just simply say three uh this this is three methyl so three myth uh three so first of all you say one two three four so that is butanol so three methyl butanol three methyl butanol okay so three methyl butanol so the parent name here is butanol with an a-l-butanol with an a-l because an audi high day has got a l at the end how the hybrid has got a-l at the end okay uh the fifth example here as you can see the functional group here if you check it through we have what we call the c uh or okay the c o o h so c o o h this one is a carboxylic acid you should be able to recognize this one so c o o like i said if you have a carbon double bonded to another atom then that carbon becomes a carbonyl carbon so even when numbering that is where you start from so this one one two three four okay so now because four it's built from the prefixes four is built so because all carboxylic acids they end in oil so oi c acid so but so from a butane you just add oil so this one will become butanoic acid butanoic acid okay so butanoic acid