hey guys welcome to igcs study bu where you can revise chemistry topics from the Cambridge igcc syllabus if you are enjoying our videos so far please don't forget to hit the like button and subscribe to our channel in this video you are going to learn part two of topic 11 organic chemistry in the previous video we explored the different representations of organic compounds now let's move on to naming organic compounds the names of organic compounds provide two key pieces of information the specific homologous series or family the compound belongs to and the number of carbon atoms present in the compound we introduced the homologous Series in the previous video we have alkanes alkenes alcohols and carboxilic acids we may identify the type of compound present if the chemical names end in one of these suffixes or endings if the name ends in a the compound belongs to the alkan family example ethane if the name ends in in in the compound belongs to the alken family example ethine if the name ends in all the compound belongs to the alcohol family example ethanol if the name ends in OIC acid the compound belongs to the carboxilic acid family example ethanoic acid we can identify the number of carbon atoms in the longest continuous chain of a compound if the chemical names include one of these parts if the name contains the part meth it means it has one carbon atom in the longest chain if it has e it has two carbon atoms if it has prop it has three carbon atoms if it has but it has four carbon atoms if it has hent it has five carbon atoms and if it has hex it has six carbon atoms these are some ways to identify the type of compound just by looking at its chemical name we can also determine the type of compound from its molecular formula or displayed formula before that a quick recap on functional groups alkanes contain only single carboncarbon bonds they have no specific functional group alkenes have a carboncarbon double bond as the functional group alcohols have an O as the functional group and carboxilic acids possess a CO as their functional group let's look at some examples of molecular and displayed formulas to determine the type of compound first we have the molecular formula CH4 and here is its displayed formula so straight up by looking at it we can see that it has only one carbon atom which indicates it has a prefix of meth in its name since it has only single bonds and no double bonds we know it belongs to the AL can family so its name will end with a therefore the name of this compound is methane next we have the molecular formula C2 H4 and here is its displayed formula looking at it we can see that it has two carbon atoms which indicates a prefix of e in its name since it has a carbon carbon double bond we know it belongs to the alken family so its name will end with in therefore the name of this compound is ethine now let's examine the molecular formula C3 H7 o and here is its displayed formula by looking at it we can see that it has three carbon atoms which gives it a prefix of prop in its name since it contains an O group we know it belongs to the alcohol family so its name will end with all therefore the name of this compound is propanol next let's examine the molecular formula C3 H7 Co and here is its displayed formula by looking at it we can see that it has four carbon atoms indicating a prefix of but in its name since it contains a CO group we know it belongs to the carboxilic acid family so its name will end with OIC acid therefore the name of this compound is butanoic acid if given the name we must also be able to draw the displayed formula of an organic compound for example methane and ethane for methane the name includes meth which indicates it has only one carbon atom the name ends with a so we know it belongs to the alkan family which means it has only single bonds now if we use the formula for alkanes CN h2n + 2 where n is the number of carbons and set n is equal to 1 we get CH4 so the displayed formula of methane would look like this the same applies for ethane where it has two carbon atoms so the displayed formula will look like this for athine the name contains e which indicates it has two carbon atoms since it ends with in we know it belongs to the alken family meaning it contains a carbon carbon double bond using the alken formula CN h2n and setting n is equal to 2 we get C2 H4 so the displayed formula for ethine looks like this for ethanol the name contains e which indicates it has two carbon atoms since it ends with all we we know it belongs to the alcohol family meaning it contains an O group using the alcohol formula CN h2n + 1 o and setting n is equal to 2 we get c2h5 o so the displayed formula for ethanol looks like this for ethanoic acid the name contains e which indicates it has two carbon atoms since it ends with OIC acid we know it belongs to the carboxilic acid family meaning it contains a carboxy group Co the carboxilic acid formula is CN h2n +1 Co now only for the case of carboxilic acids n is the number of carbon atoms in the molecule Min -1 the minus one is necessary to correctly account for the carbon atom already included in the co group therefore for ethanoic acid n is considered to be one so the structural formula is ch3 co so the displayed formula for ethanoic acid looks like this that concludes part two of topic 11 organic chemistry are you enjoying our videos are they helping you here's a way you can show your appreciation and support our continued efforts you may use YouTube super thanks to send us thanks hope this video helped you please share your thoughts in the comment section be sure to check out our other videos from our playlists thank you for watching and please don't forget to subscribe to igcc study bu for more revision videos bye