go through everything topic by topic
I've decided how about we just go
through everything at once and I'll just
simply time-stamped the the V sub topics
in the comment section below so without
further ado let's have a quick look at
the syllabus content and get right into
it so the first thing I want to be
looking at is naming organic compounds
and this section will make a lot more
sense once you sort of understand the
individual sub topics with alkanes
alkenes alcohols carboxylic acids and
esters so it might be advisable that you
just sort of listen to what I'm saying
now and come back to the section after
you've covered the rest of the video but
the the main idea is that organic
chemistry in organic chemistry you find
sort of substances that have certain
functional groups and functional groups
are basically groups of atoms
responsible for the characteristic
reactions of a particular compound and
so for the most part organic chemistry
you're just dealing with sort of carbon
chains right so let's just screenshot
this for a moment
for the most part you're just dealing
with sort of carbon chains of a certain
length with certain functional groups
attached for example if you take a look
at the alcohol over here the functional
group that you find is the Oh H group
attached to a carbon so if you find that
you have a carbon chain with an O H
group attached you instantly know that
this is the alcohol functional group and
this functional group which is again the
group of atoms that is responsible for
the characteristic reactions of the
alcohols basically then you know that
this compound is an alcohol and so why
I'm talking about this is because you
really do need to be able to immediately
figure out or be familiar with the
functional groups and we will go through
each of these individually throughout
the video but the functional group of a
compound basically that takes most of
the name each of these functional groups
have a specific name attached to it so
if you have an alkane which has a
functional group of just a carbon
attached to a carbon with a single bond
then we'll end with the name Ain and
alkene that has a functional group of
carbon-carbon double bond whoa and with
the name in an alcohol as we've
described before we'll have the
functional group O H and that will end
with the name a no B carboxylic acids
and with something and Noack acid and
they have the functional group of a
carbon attached to an oxygen with the
double bond and towards that carbon as
well there's an always group of tests as
well so these are the functional groups
that you need to know but again we will
be covering them individually esters are
a fairly unique case it's it's basically
when a carboxylic acid reacts with an
alcohol and we will dig into this in a
bit more detail later so basically
naming an organic compound comes into
three easy steps except for the esters
esters are unique but for the most part
you can do it in three steps right you
got the first step is to find these
suffix which is the end part of the name
and as we described before this is
dictated by the functional group of the
organic compound then you need to find
the prefix which is simply the front
part of the name and that's dictated by
the number of carbon atoms and the
longest chain of the of the molecule
generally and I just here so you're
gonna be only looking at a single chain
they're not gonna give you branches and
things like that so it's gonna be pretty
easy and the third step is define the
position of the functional group because
that matters as well but it's it's the
third step here isn't exactly relevant
for your course cuz generally they're
not gonna ask about it but I think it's
just good to be way aware anyway and so
I think the easiest way to do this is
just just to take a look at this
molecule here and give you an example so
if you take a look at this molecule
right as I said before this is the OAH
functional group so we immediately know
that because it has the Oh H functional
group it is an alcohol and if you take a
look at this
these bullet points here over here you
can see that alcohols will always end
with the name and all so it's gonna be
something and all but what is the front
part of the name and that's where the
prefix comes and you take a look at the
number of carbon atoms and so one carbon
atom is myth two carbon atom is if three
carbon atoms is perp and so so on and so
if you take a look here if you count the
number of carbon atoms inside the chain
of this molecule you have one you have
two uf3
and therefore it's true as you see on
the table here towards the right so
turpan all is the name of this organic
compound now the last step three is to
find the position of the functional
group and this is quite important
because if you take a look at these two
molecules here the left and the right
they are very very similar molecules but
if you can spot the difference the only
difference is the functional group and
the first molecule is attached to the
third carbon and the first and the
second and then this molecule here on
the right the functional group is
actually attached to the second carbon
now how your number the carbon is
actually really important you know how I
just said that the oah oah functional
group is attached to the third carbon
this is in fact quite wrong because if
you actually think about it
you can also equally argue that it's
like attached to the first carbon
because if you read from right to lift
it's one two and three and we're always
gonna assume that the functional group
is attached through the lowest number
carbon and we're gonna start the chain
from there well he's counting the chain
from there so instead of going one two
three and saying that the functional
group is attached to the third carbon
instead when let's that's that's the
wrong assumption because an organic
chemistry as I said we're gonna attach
it to the lowest number carbon so not
three and one in this case and we're
gonna count the chain going that way
there so this last carbon would become
the third carbon instead and so you
would actually dictate or denote that
this is on attached to the first carbon
by riding 1-propanol and the number at
the front suggests that it has attached
to the first carbon now if you take a
look at the second carbon because
despite the fact that they have equal
amount of you know molecules in them
they are structurally different because
again the hydroxyl group or the alcohol
group or the functional group here is
actually attached to a different carbon
as opposed to the first one and we call
these structural isomers which are
basically molecules that have the same
molecular formula and so it's basically
it's got the same amount of molecules
inside them but they're frog they're
structurally different and so you would
denote this isomer as to propanol but
again I don't really think the the
numbers are so much important for your
course generally they will sort of add
the functional groups towards the end of
the molecule and so you don't you can
sort of ignore the number if it's on the
attached to the first carbon like so but
I think it's just important for you to
note that indeed in the real world the
position of the function functional
group matters and they will start to get
picky about that after I just saying
when you get to a levels but either way
most of what you look what you'll be
dealing with will be simple organic
compounds so the first two steps are of
the most importance there so it really
is just about you being able to
recognize functional groups and knowing
what you know makes an alkane alkane
alcohol and you will develop the skill
as we move throughout the video and
naming the compound should be pretty
easy after that so the topic of fuels is
not a really big one are there are three
main fuels that you need to be familiar
with you've got coal you've got natural
gas and petroleum but most of what
they'll ask you in exams would be the
idea that fractional distillation can
separate petroleum it's more useful
mixtures of hydrocarbons and
hydrocarbons and molecules that only
contain carbon and hydrogen and we call
these fractions so if you take a look at
petroleum here you can actually gain a
lot of different fractions like residue
fuel oil heating oil diesel paraffin and
petrol and each of these have different
users petrol can be used in cars
paraffin can be used for aircraft fuel
diesel can be used for fuels for cars
lorries and buses heating oil can be
used for fuel for central heating fuel
oil can be used as fuel for ships and
power stations and residue can be used
for roads
and roofs and bitumen but there isn't
exactly a lot of explaining to do here
it's just for you to be aware of the
names of the different fractions and
their individual uses so homologous
series is a series of compounds with the
same function good we took a look at
functional groups before we've got you
know the alcohol functional groups that
has the Oh H group attached to the the
organic compound we have you know
various functional groups and the main
ones would be alkenes alkanes alcohols
and carboxylic acids and each of these
have unique sort of groups of molecules
that sort of define the functional group
but homologous series are molecules with
the same functional group but the main
differences are that they have different
carbon numbers that the different total
number of carbons inside the structure
that is in the chain so they're the
characteristics of homologa series would
be that all members of the series can be
represented by the same general formula
which is just basically a formula that
tells you if we have a certain amount of
carbons then how much hydrogen's you'd
have in that particular molecule so
consecutive members of these series will
defer by one carbon and two hydrogen's
and they'll all share sort of similar
chemical properties because again I said
functional groups dictate the chemical
properties of the compounds and every
member of the homologous series will
have that particular functional group so
you can expect the chemical properties
to be similar the physical properties
along these series locks actually also
change in a fairly predictable way as
well so this is an example of the
homology series of alkanes now alkanes
the functional group I mean really
really technically speaking alkanes are
lacking in functional group but for the
sake of your course the functional group
can be said to be the carbon-carbon
single bond so alkanes are hundred
carbons that only have carbon-carbon
single bonds and the carbons are
attached to hydrogen's with single bonds
as well so if you have a molecule that
only has carbon and hydrogen and you
only see single bonds in them then you
know that it's an alkane and so if you
took a take a look at the homologous
series of alkanes each of them have the
same functional group
you can see that from number one to
number five and beyond all of them will
basically have the same functional group
of carbon-carbon single bonds only and
so the idea is that the first member of
the series will have one carbon the
second member will have two carbons and
you're just basically lengthening the
carbon chain and the general formula of
alkanes is cnh2n plus two this is a
formula that tells you if you have a
certain number of carbons and you'll
have a certain number of hydrogen's
relative to the carbons and you can see
that it makes sense for example ethane
you've got two carbons and therefore two
times two plus two will give you six or
c2h6 as the molecular formula of ethane
which is the second member of the series
so you can see that you're simply just
increasing the carbon chain as you go
throughout the series and this is also
why each of the members only differ by
one carbon and two hydrogen's so let's
actually go through each of these
different functional groups the first
one that you'll have to know is alkanes
which again are hydrocarbons with the
same general formula that I showed you
before cnh2n plus 2 and you do need to
memorize this and so remember I said
that the functional group of alkanes
that they only have carbon-carbon single
bonds and so they're also highly carbon
as well so basically because they are
all single bonds no more atoms can
actually add on to the molecule and so
they are described as saturated
hydrocarbons and one really quick
important thing that I should say is an
organic chemistry because you're mainly
dealing with the carbon chains you need
to be able to understand that if you
have a carbon chain like this each
carbon can hold a maximum of four single
bonds or four bonds in total so
generally they're gonna be let's just
take a look at this molecule propane
whenever you're drawing a molecule you
need to make sure that each carbon has
four bonds to it it can't have any less
I can't have any more it can only have
four bonds and so if you take a look at
these single bonds you can see the first
carbon has four bonds the second carbon
has four bonds and the third carbon has
four bonds right so
one two three four one two three four
and so what but but if if you say draw a
molecule and it looks something like
this right then you know that
something's wrong because this carbon
only this carbon here only has three
bonds so you know you're messing up on
so you know you should actually draw one
and fill it in with the hydrogen is four
if required you also might get molecules
like a carboxylic acid which has the
functional group of carbon oxygen double
bond and an alcohol and this is the
functional group and even here this
carbon you can see that it's got four
bonds you've got one two three four of
course double bond has two single bonds
so there's four bonds and total so
everything makes sense so whenever
you're doing a molecule or organic
molecule just make sure triple check
that each carbon that you have drawn has
four bonds because it can't have any
more it can't have any less now so with
that in mind because alkanes only have
single bonds they don't have any extra
space for carbon bonds to make extra
bonds with other molecules so they're
described as saturated hydrocarbons and
so generally they're unreactive because
of their saturation and but the two main
things that they undergo with the
combustion and chlorination and we will
go through that but again the alkane
functional group the name will always
end with the name n so here is the
homologous series of alkanes that we
talked about before and so the reactions
of alkanes would be combustion which is
basically burning the the molecule in
air right and so it's simply just
reaction between the organic molecule
and oxygen which is in the air and the
complete combustion of alkane which is
when there's sufficient oxygen to react
with all of the hydrocarbon and will
will give you carbon dioxide and water
as an example show here now the
incomplete combustion of alkane is when
there is insufficient oxygen so they
enough oxygen to react with all of the
organic or all the alkanes and so what
happens then is instead of getting
carbon dioxide you'll get carbon
monoxide and water so combustion is are
pretty simple simple sort of equation to
learn the the other one is substitution
and alkanes can react with chlorine and
bright light or UV light to give a
mixture of chloro alkanes and so one
hydrogen is substituted by one chlorine
atom in the process and if you have
enough chlorine molecules present then
you can continue the reaction and more
and more of the hydrogens in the
molecule will actually be sort of
substituted as well and this is easiest
explained when I draw the molecule out
so if you these are basically the set of
reactions that will be happening as we
go down but to sort of diagrammatically
represent this we've got a molecule of
methane and methane is methane as an
alkane because there's only got single
bonds attached to the carbons and it's
also an hydrocarbon and so if you react
that with chlorine and the presence of
light what will happen is the chlorine
from all the chlorine atom from the
chlorine molecule will actually come in
displace or replace one of the
hydrogen's so there's a substitution
going on so these basically swap places
and so what then get is chloromethane
which is methane with one chlorine that
is has replaced the hydrogen and HCL in
the process now again you can actually
continue this reaction so if you have
another set of chlorine molecules these
two can actually substitute and you can
end up getting a dichloro
methane suggesting that there's two
chlorine molecules and the two chlorine
atoms in the molecule now right and that
can continue on until you you can
actually even replace these two
hydrogens so you get one carbon bonded
to four chlorine atoms which would be
tetrachloromethane but it's a very
fairly simple sort of idea there
the next thing we're gonna be looking at
is alkanes and alkenes are fairly
similar to alkanes they also
hydrocarbons meaning they only contain
carbon and hydrogen so if you have a
molecule that only has carbon and
hydrogen in it then you know that it's
out there gonna be an alkane or an
alkene of course the differentiating
factor is that alkanes uncontained
single bonds and alkenes actually have
the functional group carbon-carbon
double bond and so therefore has a
general formula of cnh2n it simply has
two times more hydrogen's all the time
than carbons and so because they have
these carbon-carbon double bonds they
can undergo adduction reactions right
and therefore they're called unsaturated
hydrocarbons remember carbons can have
up to four bonds to them so if we take a
look over here
this is a molecule of ethene
it's an alkene because you see that it's
a hydrocarbon and it has a carbon-carbon
double bond now imagine you were to
break apart this metal double bond here
right so you just simply break it into a
single bond what that means is each of
these two carbons only have three bonds
now remember carbon must have four bonds
so that means there's one more room for
a molecule to jump in and get added to
the ends over here and so these are what
most of the reactions that we'll talk
about regarding alkenes will be which is
simply addition reactions molecules just
add on to the molecule by breaking apart
the carbon-carbon double bond the first
thing we're gonna be looking at sorry
this so this is the homology series of
alkenes we got if in it starts from
ethene because you can't have a
carbon-carbon double bond which is the
functional group of alkenes without
having two carbons to begin with so
Athene is the first member of the series
here and you just increase the length of
the carbon chain by one as you go down
the list but yes so actually I think
what we'll start by doing is looking by
looking at the manufacturer of alkenes
right so alkanes are made by cracking
alkanes
so the large alkane molecules obtained
by fractional distillation of petroleum
actually passed over heated catalysts
such a silicon oxide or aluminium oxide
and these larger alkanes are broken down
into simpler alkanes alkenes and maybe
even hydrogen so there's various things
that could happen but I'm sure the first
scenario is that the alkane breaks apart
into and now cane and an alkene right
and so in this example here decane which
has 10 carbons and 22 hydrogen its
breaks apart into octane and ethane of
course octane is an alkane and has the
general formula cnh2n plus 2 whereas
this is an obviously an alkene with the
general formula if it has two carbons
cnh2n so two two times more hydrogens
then carbons so if you look at a
molecule and you just sort of figure out
what what general formula it falls under
then you can distinguish whether it's an
alkene or an alkene but either way you
can either have this scenario here we
get an alkane and an alkene forming and
this is nonspecific right you don't
always get octane in ethane you can get
other other things as well for example
and the second example you have the same
molecule decane but you can actually
split that into this alkane and this
alkyne so it's different from the first
scenario but the idea is if you add
everything up you should still get the
same number of carbons and hydrogens
that you find in decane so seven carbons
here three carbons here so 7 plus 3 is
10 that makes sense and 16 plus 6 is 22
as long as that's all adding up then it
doesn't really matter the other
situation is that you might form two
alkene molecules or varying carbon
chains along with a hydrogen and so the
same alkane here decane will be broken
apart into this alkene another alkene
and remaining hydrogen as hydrogen gas
there are three scenarios here that can
potentially happen when you crack
alkanes to make alkenes so again when we
look at the reactions of alkenes most of
them will be
addition reactions and there are three
main molecules that can add on to
alkenes be bromine hydrogen and steam
which will be the ones that we'll be
looking at so the first one would be
bromine and bromine has an aqueous
bromine basically has a brownish orange
color and so what happens is if you have
some sort of alkene which has has the
double bond and this is ethene or
ethylene which is just basically another
word to say if een bromine molecule will
come along and actually break apart the
double bond of carbon and add onto it
remember once you break the
carbon-carbon double bond each carbon
has one more bond to four for other
molecules to attach onto or other atoms
attached onto in this case the bromine
molecules will attach onto each carbon
respectively and so what you're getting
is this molecule here which is die bromo
ethane and in the process
you get the disappearance of bromine
which is the which has a brownish color
so over time as the reaction happens the
brownish color of Romel s will actually
turn colorless and that is a test for
alkenes and suggest that there are
alkenes present because the reactions is
happening so if you want to test for the
presence of alkenes basically you need
to add bromine to it and if it turns
colorless then you notice some sort of
reaction is happening and the reaction
would be the reaction with some sort of
alkene suggesting that that is a
positive test suggesting that there is
indeed and how keen somewhere and in the
substance that you added the bromine to
so that's a good test for alkenes and
you do need to know that the other
addition reaction would be with hydrogen
and so hydrogen reacts with alkenes to
produce alkanes remember because alkanes
are simply hydrocarbons that have
carbon-carbon single bonds and they will
attach their hydrogens with single bonds
as well so if you were to break apart an
alkene like ethene here and you were to
add hydrogen to each of these respective
carbons and break apart the
carbon-carbon double bond you'll simply
just get an alkane and so you get
anything and you add the hydrogen to it
and you'll get ethane in the process
there are certain conditions that year
that are required for this reactions
worked or they're the
temperature must be around 150 degrees
and you need a nickel catalyst and so
these conditions are really important
and you need to know each of the
conditions they've required for each of
the different reactions the last one
there's the addition of water and water
can react with alkenes to make alcohols
this type of reaction is called
hydration simply because you're adding
water to something the conditions
required for this reaction would be a
temperature of around 300 degrees a
pressure of around 60 atmospheres and
phosphoric acid catalyst and so what you
get would be ethylene or ething again
and you've got water and what actually
happens of course is the carbon-carbon
double bond breaks apart and you have
the water breaking apart into the Oh H
group and the H group and each of them
add on to the carbon respectively so if
I were to sort of draw that out water of
course is oxygen attached to two
hydrogens the water will sort of break
apart here so you get H and O H and the
H will go over here and the O H will go
over here and so therefore you must have
caused break the single the double bond
of the carbons they're allowing for the
extra bonds to occur and so therefore
you get this molecule here in the
process and because it now has the O H
functional group attached to the carbon
then that is indeed an ethanol or an
alcohol and we will be going through
alcohols in the next few slides but of
course the idea is that if teens or
sorry alkenes undergrow addition
reactions and the three main molecules
of addition that you need to know would
be as I said bromine hydrogen and water
and bromine is a fairly good test to
dictate the presence of alkenes simply
because of each color change that it
comes with it so talking about addition
polymerization is the formation of a
long chain of molecules called polymers
from a large number of smaller molecules
so I think of course
has a structure here and what you can do
is actually break apart the
carbon-carbon double bond just like we
did with the others and this unit can
actually join with another unit and so
if I were to draw it out right if you
have the ethane molecule if you break
apart this double bond then you have
room for two more comments just like
normal addition but this unit this
entire unit can actually add on to it so
for example like this and this is
another if a molecule that it's just
breaking apart its double bond and you
can see that this unit can be repeated
over multiple times by just simply
breaking apart the double bond and
adding one unit onto the other and so
what you get is this molecule or this
unit repeating yourself over and over
and over and over again and so therefore
you would denote that and then in this
sort of format here where you just put a
square bracket around the unit and you
just chuck down the letter n down below
suggesting that there's multiple units
of this single unit and the and the
polymer which is basically the long
chain that is formed from these
individual units so the third thing that
we're going to be looking at is alcohols
and so the alcohols have a general
formula of cnh2n plus one o H and H of
is of course the functional group that
you find in alcohols and they all end
with the name all and if you look at the
homologous series
it starts with methanol with one carbon
and it's gradually lengthens into two
carbon chains three carbon chains into
ethanol propanol and butanol along the
way but of course they all have the same
functional group of all age groups
attached to one of the carbons and so if
you take a look at the ethanol
manufacturer ethanol can be manufactured
by two main methods the catalytic
hydration of ethane and fermentation we
as
we looked at the hydration of ethane
when we took a look at alkanes and so if
we were to revise that of course you've
got the carbon-carbon double bond and
ethane and you would simply add water to
that under the conditions of 300 degrees
60ms fears and phosphoric acid catalysts
and you would therefore create the Oh H
functional group attached onto the
carbon as a result and so that would
form the molecule ethanol and so the
advantages of manufacturing ethanol this
way would be that there are no waste
products and internal production occurs
continuously the disadvantages would be
the use of crude oil which is
non-renewable and requires a lot of
energy for the maintenance of these of
these conditions here high temperatures
and high pressures the other way you can
do it is fermentation and fermentation
is the chemical breakdown of glucose by
yeast or sort of any other
microorganisms and so glucose is broken
down and you form ethanol and carbon
dioxide in the process carbon dioxide
and it's an ethanol as the products here
the entire reaction is catalyzed by the
the yeast enzymes which are basically
biological catalysts and so the
advantages would be that it's renewable
and you're using less energy because
list temperatures and pressures are
required for this compared to the
catalytic hydration of ethane but the
disadvantages is would be that they're
slower and in production
it's a batch process meaning that new
you need a new sort of batch of yeast
once the yeast die and it produces
carbon dioxide which is theoretically a
waste but yeah there are their main two
main methods of making ethanol and came
with MOS you to be aware of that along
with its relative advantages and
disadvantages so the properties of
ethanol would be that they burn in blue
flame and the combustion of ethanol will
give you carbon dioxide and water just
like the combustion of alkanes ethanol
can be used as a fuel as a solvent and
paraffin and foreign industries and some
cultures and alcoholic drinks and to
make other organic chemicals
such as esters and so the the next thing
that we're gonna be looking at this
carboxylic acids and carboxylic acids
have the general formula of cnh2n plus 1
with the COOH functional group ends with
the name a weak acid and so if you take
a look over here these are the homology
series of carboxylic acids and you can
see the lengthening chain as we go down
through the members but the idea is that
ethanoic acid manufacture can happen by
one the oxidation of ethanol by
fermentation so the SE dabangg of
bacteria can oxidize or ferment ethanol
into ethanoic acid so it's a simple
equation you have you have ethanol you
get you add that to oxygen and when the
presence of bacteria you get the the
ethanoic acid and water and this is of
course
ethanoic acid because it's got two
carbons in the carbon chain oxidation of
ethanol can also happen by the acidified
potassium manganate which is an
oxidizing agent so when ethanol is
heated with an oxidizing agent such as a
certified potassium manganate you get
Illinois cancer being formed in the
process like this equation over here so
you've got the ethanol getting added to
the oxygen which is the process of
oxidation and you get ethanoic acid if I
were to draw that out it would look if a
no weak acid would look like this so
please don't get confused when you see
the o H group and immediately associated
that with alcohols if it's this entire
thing is the functional group and that's
indeed carboxylic acid so if the carbon
is bonded with a double bond with the
oxygen and also has the o H bond
attached to it as well so moving on are
the properties of ethanoic acid would be
that it because it's an acid or
carboxylic acids of course including
ethanoic acid
a weak acid this means that they
demonstrate typical acid properties and
they only partially ionized an aqueous
solution which is what weak acids are
and so the the general reactions with
all of our properties of acids would be
they have the classic metal plus s
reactions giving you salt and hydrogen
and and you've got the base plus acid
and the carbonate plus acid reactions
that you need to know of the only real
thing here is it's exactly the same as
you do a normal acid plus sort of metal
reaction for example if you have a
magnesium added with ethanoic acid
you'll actually get magnesium it's a no
eight as the salt and so if you're sort
of confused about how the ethanoic acid
makes iron eise's basically you have the
ethanoic acid being like this and you
get the ionization of one hydrogen which
is of course the properties of acid that
makes hydrogen ions along with the
structure here and so if you know that
then if you're adding that to magnesium
is simply magnesium is combining with
the ethanoate ions and so if you of
course change the oxidation states
around you'll find you get mg ch3coo and
you put that in brackets too and just
like how you just formulate any sort of
other chemical formula
okay so moving on our carboxylic acids
and alcohols if they react with each
other you can form ester and the
conditions required for this reaction is
heat and concentrators of uric acid so
if you have any sort of carboxylic acid
like so you'll have the functional group
C or Oh H and if you you can actually
react that with an alcohol because the
Oh H group of the carboxylic acid will
actually react with one of the
hydrogen's on the Oh H group of the
ethanol and what do you get you get
water because you got a ch2 and O and so
these groups of atoms leaves as water
and you get a direct link happening
between the carbon and the oxygen
so the carbon from the from the acid and
the oxygen from the ethanol or the
alcohol whatever alcohol it is in this
case is ethanol and so you get this
structure here and this part or the
carbon oxygen bond that you get is
called the ester link and this is an an
ester and esters are always named
something I owe something oh eight and
if you take a look at the structure the
alcohol part of the ester always comes
first and in the alcohol part you know
it's got two carbons so it's if so it's
a file and the carboxylic part comes
second which is also two carbons towards
it as well so this is if they'll even
though sorry actually I'm just gonna oh
sorry yes no in fact I I miscalculated
that so the alcohol part is still
correct is ethyl because it's got two
carbons but I didn't see the last carbon
there so it's here we go
three one two three carbons so it's proq
propanol wait if they'll sew something
else something or propane o8 right and
so the the only really counterintuitive
thing is that when you when you name
Esther's the the alcohol part which is
seemingly the last part of the mr. X
becomes free so if they'll propanol wait
in this case if this had two carbons
then there be if so if the no way had
add five that's buttes so butanol wait
and so forth right so polymers are large
molecules built from a smaller units
different polymers are built from
different monomers and have varying
linkages between the monomers so there
are two main methods of polymerization
this addition and this condensation we
took a look at addition before so we're
gonna be taking a look at condensation
and which in a condensation reaction
three monomers react together and join
and during the reaction a molecule or
one order model or water molecule sorry
is lost in the process and therefore we
call that condensation if we were to add
something we would call that hydration
everywhere to add water to break
something down we call their hydrolysis
but we will be going through that in a
bit more detail later all the synthetic
and natural polymers that we will be
looking at in this course are forms of
condensation polymerization you've got
nylon you got terylene being synthetic
polymers and we've got proteins and
carbohydrates being natural polymers so
the synthetic polymers are mainly poly
amide or nylon that you need to know so
the two monomers that you find in these
are the dicarboxylic acids which is a
certain group of molecules which we
would sort of label it's just a box of
some sort with two carboxylic functional
groups added onto each side like over
here and you've got the diamine which is
the in it's got a block of molecules
which you don't need to know you just
put it as a block like so and it's got
two nh-2 groups attached on either side
we call that a tie amine and so these
two monomers join together and so the
OAH group of the carboxylic acid will
react with an H from the nh-2 group over
here and so you get a direct link
between the carbon and nitrogen and this
is called the mi
this is sort of similar to what happens
in an ester remember except an enesta it
was an oh wait group and the h of the o
h reacts with the always with the
carboxylic acid but either way the
hydrogen from the nitrogen group here
reacts with the always grew up in the
carboxylic group and you get a direct
link formed between carbon and nitrogen
and that's an amide link and if you were
to sort of continue on that chain you
would get a series of molecules like
this and that is the official sort of
diagram that is listed in your syllabus
polyesters or tetra lien the two
monomers argh anti carboxylic acids or
die acids the same sort of monomer
except the second one is a die all so
this is exactly sort of similar to an
ester and in fact it is as an ester link
where the OAH group of the carboxylic
acid reacts with the H from the O H and
a group from the alcohol and so if you
join those two together again you get
the direct link between the carbon and
the oxygen and so you get the ester link
happening there and you also get
hydrogen being removed because again
these molecules here make hydrogen and
that's being removed to form the bond
there so if you were to sort of chained
it up you'll get a molecule that looks
like this to the right the natural
polymers consists of proteins which are
built from amino acids and monomers that
are joined via amide links through
condensation polymerization exactly like
we looked at before it's just different
units so basically we've got the
carboxylic acid group and you've also
got the amine group so the the the amino
acids will basically have at the
carboxylic acid group and the amine
group as well attached onto the molecule
so if you were to again similar thing
the Oh H group from the carboxylic acid
will join or will form water with the
hydrogen group from the amine group that
you find in the amino acids and so in
the process of condensation removing
that part that water will bond the
carbon and the nitrogen and you get a
peptide or an amine link forming you can
actually reverse a process by adding
water to break down the form the polymer
back into its simplified amino acids or
monomers and so that here is just
demonstrating that you can actually
hydrolyze it by boiling it with
hydrochloric acid to make it back into
amino acids the last thing is
carbohydrates which is complex
carbohydrates polysaccharides are made
from larger number of simple sugar units
that are joined through condensation
polymerization so and sugars you have
the sugar monomers which are basically
sort of dials with two hydroxyl or
alcohol groups and so if you were to
simply use the same process the O age
group will just join with a H group from
the other Oh H group and so if you form
these you get water happening and you
remove the water that's condensation and
so you can join everything together and
you'd form a large chain of these of
these sugars and so this is actually
wrong I'm just gonna remove that but
again you can actually hydrolyze it back
as well so the condensation is removing
water to join everything off to make
larger compounds but the polysaccharides
which is the larger compound you can
convert that back into simple sugars by
hydrolysis and this reaction can be
catalyzed by enzymes or heating with
dilute hydrochloric acid as well so a
structural isomerism we talked about
this and a and the prior sort of life
but basically they're the same molecule
that have the same molecular formula but
they have different structures and
that's much to do with how the carbons
are attached you can see that in this
molecule here butane a single chain but
isobutene which is an a structural
isomer of this molecule here as it's
different because the carbons attached
differently and same with these ones
here so thank you for watching guys it
has a long video but I will timestamp
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