AS LEVEL ORGANIC CHEMISTRY IINTRODUCTION

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 are looking at a s level organic chemistry and the topic is formulas in organic chemistry by the end of this video you will be able to define organic chemistry thereafter you will familiarize with the common terms used in organic chemistry and finally you will know the different formulas that are used in organic chemistry [Music] for starters let us define organic chemistry organic chemistry is the study of carbon containing compounds except carbonates carbon monoxide carbon dioxide and carbon disulfide carbon containing compounds are known as organic compounds the composition of atoms in an organic compound is expressed using formulas there are different types of formulas let's have a look at the terms used in organic chemistry number one we have the general formula general formula is a formula that represents a homologous series of compounds using letters and numbers a homologous series is a group or family of organic compounds that have the same functional group the same formula and the same chemical properties a functional group is a group of is an atom or a group of atoms which determines the chemical properties of organic compounds chemical properties generally refers to the reaction reactions particularly to a substance so chemical properties generally refers to the reactions that a particular substance undergoes structural formula is a formula that shows the atoms how the atoms are bonded to each carbon atom in a molecule so the structural formula is a formula that shows how the atoms are bonded to each atom in a molecule skeletal formula skeletal formula is a simplified displayed formula with all the carbon and hydrogen bonds removed the skeletal formula is a simplified displayed formula with all the carbon and hydrogen bonds removed the displayed formula is a 2d which means two dimensional so it's a 2d representation of an organic molecule showing all its atoms by their symbols now remember symbols of atoms on the periodic table so the displayed formula is a 2d represent a representation of an organic molecule showing all its atoms by their symbols and their bonds uh whether they are single double or triple so that is a display formula now i'm just giving the definitions here very soon you will be able to see the pictorial examples of what we are talking about let's have a look at them now for more of that series in organic chemistry we have quite a number of homologous series in organic chemistry so this represents an opportunity for us to understand the terms that we have just defined now we have said the fact here as you can see there's functional group so there's a column for functional group right here the first column then we have the second column for the general formula then we've got the structural formula you know what the displayed formula and we've got the skeletal formula and finally they give us an example of the name for that particular family so a homologous series is a family so the first family simplest of them all is the alkene family so now the alkene formula the alkene family they represent to the general formula cn h2n plus 2. now remember we said a general formula it represents a homologous series using letters and numbers now this n here in organic chemistry the n is going to represent the number of carbons okay so for example if we are dealing with the first member of the alkenes which is methane then it's going to have one carbon so where there is n here it means that you're going to replace it with 40 one then also here we put one so here we're going to have c1 h then 2 times 1 is 2 2 plus 2 is 4 so we are going to have ch4 then you have come up with a specific formula of a member in this family here so it's just an example all right so now that formula ch4 can you see when we go to the structural formula now on the structural formula here you discover that every carbon now remember carbon is we call it a tetravalent atom meaning it needs four bonds in it to be stable and bonds are represented by a line so a line represents bond and a bond represents two electrons okay so when you look at this carbon this is a carbon so it has four bonds around one two three and four even this one this other one also it also has four bonds so this is one two three and four so now have you seen there's there's this part here that has been highlighted so this one is what we call the functional group so alkenes will behave the way they behave because of this functional group here and this one we call it the carbon carbon single bond carbon carbon single bond because remember a line simply represents a bond okay so this is the functional group now the structural formula is just how these atoms are connected to each other it shows how these atoms are connected to each other so the structural formula and the displayed formula are not that different after all so here this is an example of the first member of the alkenes alkenes is a famine so it's like the first bond in this family is methane so methane like i said it has got one uh it is number one carbon so it uh so this one is not uh it's a ethane actually not methane so if you're looking at the second second member and it has got two carbons then you're going to put a two here so this one becomes c2 then if you put a 2 here it means 2 times 2 which is uh 4 okay which is 4. so this 4 here so this uh 2 times 2 which is 4 here plus 2 it becomes 6. so the formula will be c 2 h6 c2 h6 and also when you go to the displayed formula here you discover that this is one two c2 then you count the hydrogens there are six one two three four five six so that's what it means don't worry you are just trying to familiar rise with these things so that is displayed formula it shows how the atoms are connected to each other and what bonds are in existence skeletal formula this is just where we use the t the lines okay so on the skeletal formula here we're just going to use the writing the lines so now when you draw a line like this one what it simply means is at the far end here at the far end of the line there's a c okay then also here in the sides here is a c so this is a c and this is a c so this is a c and this is a c now every carbon remember it needs four bones so if you write a c here it means that this this line will represent one bond so it needs three other bonds one two three so here at the far end we have ch3 also here ch3 so this c and the c that is two then the three hydrogens that are here and the three hydrogens that are here they are making six hydrogens which is this one so this is skeletal remember skeletal at the ends of every line it represents a carbon even if we had to put a bending let me just try to re-emphasize on this one using a pen so i am saying here we can assume that there is a c now a ac it needs four bonds so it will need that one okay and that one and also that one so this one will represent h h h so here is as good as writing ch3 also this side also here also there is a c which will also going to have one okay two and three so also now these these ones here they just represent uh the hydrogen so this is hydrogen also this one here will represent the hydrogen also this one here will represent the hydrogen that is the rule that you should follow about the skeleton now we don't show these i'm just trying to explain the meaning so when you draw a line it means automatically at the far end there is a c and there is a c and every carbon it needs for bond so it represents if you are going to add three one two three plus this one already drawn next four also this one also here one two three plus this one already drawn it also makes it what it four okay let's take for example even if we had something like this okay something like this so it means that here here there is a c also here at the far end there is a c also here where it is bending this is a c now if it is bending like that meaning here there is h there and also this h so that this c which is in between what one two three four that's what it means so we are talking about the skeletoid formula so i hope i have explained that remember we are looking at homologous series which is a family now families like you and i we've got a surname there's a family name so a sunny for example chamber zimbabwe now zimbabwe is my family name meaning every other of my siblings we have another sibling maybe there is there's maureen marin zimba there's another christian zimbabwe barista zimba so everybody is going to have their own name and the surname so also here for the alkenes all of them they are send their sun here is a and e now this one is called a suffix look into details later on so it's called a suffix so a surname is called suffix so here in the family of alkenes we're going to have those things that if you remember your form 5 organic chemistry we had things like methane ethane propane butane pentane xn and so on and so forth so there was a n e at the end so just take that one more like assigning so we have looked at four types of formulas general formula this is the formula that you can use to come up with a specific specific formula of a certain family of a certain member in a given family so the structural formula is just showing the structure of that particular formula so now from the general formula if we substitute according to the numbers here the formula that we get is what we call the molecularity formula then from the molecular formula you can now draw a structural formula so the structural formula and the displayed formula it isn't very much different then thereafter we also have the skeletal formula and i've explained what that one means all right another example is the alkene okay we also have the alkene family so these ones they are sun name is e and e so you are you're going to have things like ethene uh propine butane uh pentine hexin and so on and so forth so e and e at the far end okay so this one they're saying the general formula is cnh2n so this n it simply means the number of carbons so if for example you have two carbon if you have two carbons meaning you're going to put a two there then also here you're going to put a two so this one will become something like c2 okay this one will become c2 then uh h so just an example so c2 then h then these two times two will be four so this one here you come up with a four so this one is what we're going to call the molecular formula then from the molecular formula you're going to draw a structural formula which is almost the same as the displayed formula so also know that the functional group for the alkene family is actually a carbon carbon double bond so all alkenes they will behave the way they behave because of this carbon carbon double bond all right we proceed so that is how it is done so this one here the c2h4 this is the one you have one two then you have one two three four now we said every carbon it needs to have four bonds around it so here we have this this a single line represents one bond so this is one two three four also here we have one two three four okay now going to the skeleto also we said when you draw one line like this at the far end there's a c and also here in the c so one line represents one bond another line represents another bond so now this one in short it means there is a c here and also here there is a c so we don't just show them so by showing this you should be able to interpret so here is a c so meaning there's an h there and there's an h there also there's an h there and also there's an edge here all right we proceed to the next example i hope the skeletal part is making sense okay we got to another family called the irenes so the irene's like here they've also explained we've got cn h2n then minus 6m so here we are simply saying n inorganic chemistry means number of carbon atoms then this m on this formula for the irenes it simply represents the number of rings so here it's just one ring so this is a structural formula then it doesn't have a displayed formula so the structural formula and the skeletal formula they are just the same so you are just trying to familiarize with uh the use of these four types of formulas that you are talking about okay we also have the halo alkene halo alkene so the formula here halo this one is coming from this is halogen okay halogen now halogen we are talking about the group seven elements so group seven elements there were fluorine chlorine bromine iodine and so on and so forth so those are the halo so meaning to the formula of the alkenes that we saw earlier on the cn h2n plus two now this one just becomes plus one then you add x where x can either represent chlorine fluorine bromine or iodine that's what it means so this uh i think the skeletal formula has been straightforward so there's a c here there's a c here but you have put something so when you put something at the end don't ever assume there is a c so for example let me just say if i drew something like this it this and this are different so when i put something at the end it means the c is not there but if i've not put something here it means there's a c so here there will be a c there will be a c at the corner here and there will be a cga so the difference between the c at the corner here and the c at the beginning is this c is going to have three hydrogens but this c is going to have two hydrogens remember the rule is that every carbon which needs to have four bonds around it okay four bonds around it okay so here you see we're going to have one uh two three four then this one here we're going to have one okay uh two then we're going to have three so one two three four so this one is going to be ch3 this one is going to be ch2 because of one two here okay and this one will be ch3 as well okay so there are several several examples that you can look at let's look at the alcohols now alcohols there are three types it's what we call the primary the secondary and the tertiary but i think the major emphasis here is you just have to master the general formula so already master the general formula then when you substitute into this one for example the first the the simplest alcohol that we can find here maybe if we put one carbon here if we put one here so it's going to be c1 then we also put one here so it's going to be ch3 or h so ch3 or h okay now let's look at this one here this is just uh the primary alcohol then when we write it in the display okay display display shows how exactly the atoms are connected and this is how they are connected for a primary then so here the functional group the functional group here is this one here the o h so alcohols behave the way they behave because of this functional group here okay so here like i said there's a c so here there is a c and here is a c i'm just trying to interpret it for you but a skeletal formula would just be written like this so there's a c here and here there's a c okay then all alcohols their names they end with or l okay so here this is ethanol so there is four l at the end here so this is the family name which is the surname so for example uh let's take for example uh we've got a girl by the name of diana so tayana one day just wakes up she becomes an alcohol so if you want to convert the name tayana into an alcohol then we are going to say tayano okay so it's going to be tayano okay so tayana tayano so you just add o l all right i hope this concept of skeletal formula and the displayed formula especially is being grasped here okay so there are a lot more that we can look at look at this is a secondary here we explain more into details but is see here for the skeletal there's also a c here and a c here so they see that is here it already has one two three so you just need to add one edge okay so if you are adding you're just adding one h okay so that is the way it is but this one is going to have ch3 ch3 and that is how it is done okay we've got more and more families in organic chemistry we've got the phenols what they are the aldehyde and a lot with the ketones because the carboxylic acids we've got the esters so all these the acetal chlorides the amines all these we're going to have time to look at each one of them in details the purpose of this lesson was for people to familiarize themselves with which functional groups are present so here these that are highlighted are functional groups they are the ones that are responsible for that family behaving the way they behave reacting the way they react and also just trying to know how to write a displayed formula how to write the schedule formula and how you can come up with a molecular formula from a general formula so that was the purpose of this video you can play pause and ask questions down in the comment sections if you have any questions then i will be able to respond to you otherwise thank you so much for listening to you next time