now this video is all about esters alcohols and carboxylic acids so let's start by examining alcohols now alcohols have the functional group o h so the first alcohol has one carbon and it has this molecular formula most importantly you'll need to be able to draw its display formula so start by drawing that alcohol functional group and then fill in the rest of those hydrogen atoms remember that each hydrogen forms one bond each carbon forms four bonds and each oxygen forms two bonds and that will help you draw it correctly now in order to name our alcohol remember that we use the mnemonic monkeys eat peanut butter and that will help us remember our prefixes so monkeys stands for meat eat stands for eath peanut stands for pro butter stands for butte and so because we're looking at one carbon we therefore know that our alcohol is called methanol and the last thing to be aware of is that all alcohols end in all so drawing the second alcohol should be nice and straightforward our molecular formula here is c2h6o so draw those two central carbon atoms add that alcohol functional group and then fill in with hydrogens because it has two carbons we're therefore looking at eats so that's eath so the second alcohol is called ethanol which is the one you're probably most familiar with because it's what's found in alcoholic drinks and it ends in all looking at the third alcohol now c3h8o draw those three carbons add your o-h functional group complete the hydrogens monkeys eat peanut means that the third alcohol is called propane notice that that oh functional group occurs here and that's on the first carbon remember the whole molecule could be rotated in chemistry you always start with the fewest number of carbons when you're naming so that's why we call that carbon number one as opposed to carbon number three the oh functional group occurs there which is why this alcohol is called propane one o however there is a second form so if i draw those three carbon atoms again this time we add that functional group onto the central carbon complete the molecule as normal so again we have three carbons which is why it's propane however this time the oh functional group occurs on the second carbon so that's why the name of this alcohol is propane 2-o now check out the statement i've made here which is that propane 1 all and propane 2 all are isomers and the reason they're isomers is because look they both have the same molecular formula but they have different displayed formulae that oh functional group has shifted and as a result we can say that they are isomers and so the definition of an isomer is that it has the same molecular formula but different displayed and then finally let's draw the fourth alcohol so as you would expect c4 h10o is the molecular formula let's draw four carbons in a row draw that functional group i'm just going to draw it here for a change on that first carbon i could have easily drawn it over here fill in the rest with hydrogens let's name it so it contains four carbons so according to this we're using the prefix butte and then we need to say where is that oh group well it's on the first carbon so we need to put a one in our name and end it with an o so that's butan one all how about we shift the position of that o h functional group let's put it on the second one this time so down here fill in our hydrogens let's name it four carbons butane the oh is on the second carbon so it's butane two all now there's no point trying to draw a third isomer for example adding the oh here because remember we can flip the whole molecule so that carbon therefore becomes the second one so that's actually it there are only two isomers of c4h10o now we need to turn our attention to carboxylic acids and i'm going to write the name of the first one which is methanoic acid notice that it's called math monkeys eat peanut butter because of the one carbon all carboxylic acids end in anoic acid now i'm not going to worry about the molecular formula because i don't think it's at all helpful here i'm just going to show you how to draw it first of all you need to be aware that the functional group of a carboxylic acid is this and so if i draw that if that's the bare necessities for that carboxylic acid we have to do is add a hydrogen in order to complete the molecule and just double check your number of bonds carbon needs to have four bonds one two three four oxygen has two one two one two hydrogen has one yeah perfect so that's the first carboxylic acid the second one monkeys eat therefore is ethanoic acid we need two carbons this time add that functional group for the carboxylic acids and then fill in with hydrogens and that is ethanoic acid the third carboxylic acid now is propanoic acid so it will draw three carbons in a row add the all-important functional group complete with hydrogens and that's propanoic acid the fourth one butanoic acid we're going to have four carbons in a chain add the functional group complete the hydrogens and we're done so now we need to look at esters made when an alcohol reacts with a carboxylic acid so the earlier part of my video becomes important now notice that this is a reversible reaction and produces water as a byproduct so it's a reversible reaction which means it can go both ways the forward and backwards direction it's an example of a condensation reaction and that's simply because a small molecule is formed as a byproduct which in this case is water so we can say that condensation reaction is when water is released one other thing you need to know is that you need a catalyst which in the case of making esters is strong sulfuric acid the last thing to mention is the ester functional group and here it is here and i'm going to show you how we form esters now and how to name them so first of all we're going to react methanol and ethanoic acid now we're going to write the word equation first of all so there's the reversible reaction you need to name the ester now now the first part of the ester's name comes from whatever the alcohol is so it'll come from the methanol here so the start of the ester name will be methyl and always follows the same structure naming esters the second part of the name comes from the carboxylic acid so it comes from the ethanoic acid so the name of this ester is methyl ethanoate and you need to add your water now we're going to draw them so there's our methanol here's our ethanoic acid so in order to form that water as a byproduct we need to lose the oh from the carboxylic acid and the h from the alcohol and it always follows in that way that the oh comes from a carboxylic acid the h comes from the alcohol and as you can see that will form h2o and then it's just a matter of sticking the remaining parts of the molecules together like so double check your bonds each of the carbons needs four bonds each of the hydrogens must have one bond and the oxygen is two yeah and just to highlight here is your ester functional group let's show that we also make water and that's it drawn so this over here is your ester which is methyl ethanoate let's do a second example now let's try ethanol and propanoic acid so reversible reaction again the first part of the ester's name comes from the alcohol so it'll be ethyl the second part comes from the carboxylic acid so it'll be ethyl propanoate we make water let's draw the ethanol and now for the propanoic acid so the ester we lose this oh here this hm and stick the remaining ends together you need to draw it nice and carefully it doesn't matter which way around you draw the atoms whether it's upside down or not it makes no difference and there we are done one thing i want to mention is that esters are sweet tasting and smelling they're volatile which means they evaporate easily and they're used in food flavorings [Music] foreign [Music]