okay so welcome and we'll pick up where
we left off here in Chapter eleven and
again like usual if you do have
questions feel free to ask him in the
chat box so where we left off was we
were talking about sort of organic
chemistry again we got into sort of a
little overview of organic chemistry
again usually organic chemistry for the
most part is made up of compounds that
contain carbon and the basis of a lot of
organic molecules are kind of like what
we see on the screen here is carbons
attached to carbons and those carbons
attached to hydrogen's and that's your
basic sort of connection that we see as
we also talked about there's a lot of
different sort of categories of organic
compounds and they're sort of classified
by certain aspects that you find on the
molecule and those sort of aspects that
we find on the molecule or were
sometimes referred to as functional
groups and depend on the functional
group that's there we'll give you a
different type of organic molecule and
they will also have obviously some
different properties depending on the
functional group that's present we
talked about a little bit of - the basic
functional group which is sort of the
carbon-carbon single bond and those are
a group of organic molecules which are
known as alkanes so sort of we're right
alkanes functional group is the
carbon-carbon single bond which means
pretty much they have all single bonds
in there no double bonds or anything
like that and that is was sometimes
referred to as a saturated hydrocarbon
saturated means that it has the maximum
number of hydrogen's per carbon and when
we talk about carbon remember carbon
pretty much wants four bonds so it's
going to continue to make bonds until it
has four and pretty much hydrogen will
kind of fill those in and that's not to
be confused with alkenes for example to
have a functional group of
carbon-carbon double bond and those are
researchers unsaturated hydrocarbons and
those are unsaturated because as we also
talked about last time every time you
put a bond on UDS to sort of sacrifice
two hydrogen's to make room for it
otherwise you'll have too many too many
bonds to carbon so we started talking
about I think we did get kind of the
first 10 alkanes they were kind of in
the middle of that right now and the
first 10 alkanes are really important
because everything in organic chemistry
is pretty much based off of those first
10 names so that's like methane ethane
propane butane pentane and so forth and
everything really does come back to
those so continuing on here butane for
example is four carbons in a row as we
see as you see there on the bottom and
this is a straight chain here of butane
and as four carbons in a row which is
butane on the bottom is sometimes
referred to as isobutane are really the
IUPAC way of naming it is two methyl
propane and as we also talked about last
time I think at the very end sort of a
way you could distinguish certain
compounds is by naming them and we're
gonna get more into how to name those
here today but one of the sort of key
things that you do when you go about
naming things is trying to find the
longest continuous carbon chain again
that carbon chain does an acid ester be
the straightest but it does have to be
the longest continuous carbon chain
without you kind of going backwards or
backtracking or anything like that
so essentially you start one way sort of
going to hit a dead end
and again the longest chain of carbons
gave you just really the base of the
name so here this was pretty easy to see
you got four carbons straight across and
again four carbons is really butane as
opposed to we come down here we really
have one two three carbons again is the
longest continuous carbon chain
you also could go one
- and upwards if you want three carbons
as well but the longest continuous
carbon chain without backtracking is
only three carbon and three carbons is
based off of propane which is where that
part the name comes from and this is
what is sometimes referred to as a
branch chain as we talked about as well
off of that longest continuous carbon
chain there's other things attached and
these are sometimes referred to as
groups and these were sometimes referred
to as alkyl groups and a group really is
something that's attached to the longest
continuous carbon chain that's again not
part of the longest continuous carbon
chain but attached to it and that is
where the two methyl comes from because
of the location of this group it's on
carbon number two and that's where the
two part of the name comes from and the
methyl part comes from the name of this
group as really we'll also talked about
here in just a second it has one carbon
which is based off of methane but since
it's not part of the longest continuous
carbon chain it's a group we put a yl at
the end of it and that's where the two
methyl part of the name comes from
so again an important thing especially
when you go about Sur naming things is
you do want to always try to find that
longest continuous carbon chain we also
touched upon this idea as well and the
idea of isomers and isomers again are
really something that has the same
molecular formula but has a lot of times
for example a different sort of
connectivity if you will and also
because it does have a different
connectivity it would have a different
name and for example here the two that
we just saw there on the previous page
the butane and the isobutene are the two
methyl propane they are isomers of each
other so
and the one that we were just looking at
here if we count up pretty much all the
carbons and all the hydrogen's on both
of those guys again we have four carbons
and ten hydrogens and the same thing
down here we have four carbons and ten
hydrogen's so they both have the same
molecular formula but they do definitely
have a different connectivity and as we
can see here as well a different name
and thus they are what are known as
isomers of each other and because they
have different names they will also have
obviously that different connectivity
and will have different properties as
well and again that's basically what an
isomer is say molecular form a different
sort of connectivity there's several
different types of isomers one type of
isomer is a constitutional isomer and
constitutional isomer is different the
way that the atoms are connected to each
other so same thing down here if we sort
of count up everything that we got going
on we got two carbons six hydrogen's and
one oxygen same thing on the right hand
side we have two carbons six hydrogen's
and one oxygen and the way that they're
connected is completely different and
they would have different names this is
ethanol this is what's known on the
right as dimethyl ether these are
actually two different types of organic
compounds we talk about functional
groups last time so this o is group here
is the functional group for an alcohol
again this would be the functional group
while this little run here of carbon
oxygen carbon is an ether also a very
different sort of organic compound as
well again although they do have the
exact same molecular formula because of
the way they're connected they are known
as isomers of each other they're also
very different in terms of their
properties so for example the ethanol on
the Left can do some hydrogen
because it has an oxygen hydrogen for
example the guy on the right not and
because the guy on the Left can do some
hydrogen bonding it's expected that it
would have something for example like a
higher boiling point right so the
stronger sort of that intermolecular
force like hydrogen body the higher the
boiling point so something like on the
left there would be a higher boiling
point in terms of sort of a reactivity
as well I'm afriad T's right word there
but in terms of solubility for example
in water the guy on the Left also would
be much more soluble than the guy on the
right again because the guy on the left
has the ability to hydrogen bond with
water well the guy on the right does not
necessarily have that ability so you
know a lot of these things even though
they are technically the same thing in
terms of elements and so forth they are
very sort of different a lot of times in
terms of properties because of those
connectivities that we see here Zod
pentane and pentane again is five
carbons and if you remember what we
talked about last time with alkanes
alkanes have that general form of C and
H 2 and +2 again here if carbon is 5 5
times 2 is 10 plus 2 is 12 hydrogen's
that's a 10 let's meet at 12 there we go
as 12 hydrogen's and that's what we see
here so this would be pentane again just
a straight old chain of carbons attached
to carbons that's sort of the condensed
form again the more structural form o
would be something like this where we
draw it out and again obviously the
hydrogen's all the way across
here's also 2-methylbutane and too to
die methyl propane these all began if
you count up everything here 1 2 3 4 5
carbons 3 5 8 11 and 12 hydrogen so
again they all have the exact same
formula but they are different so if we
look here we have one two three four
carbons it's the longest run of carbons
you could get and that is where the base
of the name comes from which is butane
again here we have this guy right here
which is a group and again it's a one
carbon group which is known as a methyl
group which is where the methyl part of
it comes from and the number two means
that if you count the carbons 1 2 3 & 4
this is at carbon number 2 is where that
name comes from so that is
2-methylbutane same thing here though it
has the same formula the c5h12 longest
continuous carbon chain is only 3 if you
go straight across if you go straight
across and up is 3 right 1 2 & 3 you go
straight across it down it's also 3 and
again 3 carbons is propane which is
where that isn't it from that name we
also have this guy and this guy which
are both methyl groups and there's two
of them which is our dimethyl part of
the name and again they are both here at
carbon number 2 which is where the name
then from the two to dimethyl propane so
again these are all isomers of each
other they all have the same molecular
formula but different connectivity again
gonna have some different properties as
well straight chain here pentane and
more branched chains over here at both
of these ends
so here's the rest of the first ten out
canes we also touched upon last time as
well and again really important to know
those first ten because everything
pretty much based off of them so let's
actually talk about how we sort of named
these guys and we've sort of touched a
little bit on it as as we've been
talking but really usually when you go
to name we usually name for the IUPAC
way of naming again the IUPAC way is the
international union of pure and applied
chemistry again they are the guys that
basically come up with all the naming
that we do pretty much with everything
and that's usually the way that you sort
of go about naming organic compounds as
we also touched upon last time there are
lots of different names for the same
compound in organic chemistry again some
are historical type names some are
common names and then obviously
somewhere like I you PA see name so it
is very very possible that you could
come across an organic molecule and
you'll actually have for example three
different names for the exact same thing
but for the most part in most classes
that you take if you should continue on
somewhere where you're doing some
organic chemistry you know the IUPAC
name is sort of like now the the more
official name if you will and usually
the name that's usually that you use and
sort of go so really there's a couple of
different sort of steps when you go
about naming and an alkane for example
and really a name an alkane or anything
else the first really big thing that you
need to figure out is the longest carbon
chain so we've been talking about a
little bit and again when you do count
the longest continuous carbon chain
it doesn't necessarily always have to be
the straightest so for example a little
bit room here
so let's just say we have you know this
sort of got here I'll put in some
hydrogen's here and we do this guy here
pops up hydrogen in Ch should do less
carbon let's say huh
so obviously on this first one if we
just count straight we have one two
three four five six seven carbons is the
longest continuous carbon chain and
seven carbons would be have a base name
of heptane so that longest continuous
carbon chain would give you your base of
your name but now if we come over here
to the guy on the right and we start
sort of looking for the longest
continuous carbon chain again if we just
go straight here we have one two three
and four and you may say yourself well
that's four so that looks like the
longest continuous carbon chain but
again here you got to sort of look at
all of your options so you could
technically go this way one two three
and then go up four five and six and
that would give me six carbons going
obviously the orange way you also should
always check every sort of option that
you could have and really your other
option in terms of sort of ways would be
for example if you went say this way one
two three four and five so we've got
five carbons that way and then we
obviously had four carbons going the
purple way
so we could see looking at all of our
options the longest continuous carbon
chain four carbons going in purple is
going in the yellow path and sometimes
once you find that longest continuous
carbon chain which in this case would be
six again that's going to be hexane as
the base of the name I find that if you
want to name it it's sometimes really
good to kind of put a box around it and
once you put the box around it you can
see what is part of sort of the main
chain and what you end up with is as you
can see there there is something that is
not really part of that main chain and
again anything that you find that's on
that structure that is no longer part of
the longest continuous carbon chain
again is what is referred to as a group
and if it is a carbon containing group
it's an alkyl group and really naming in
terms of organic chemistry is all about
sort of location and you're basically
telling everybody exactly where you
could find things and what is there and
where it is and that's really the basis
of sort of this naming so again hexane
would be the base of our name now when
we look at what's attached there in
terms of that alkyl group
it is based off of one carbon and even
the groups that are attached that are
not part of the main chain are also
based off of those first 10 alkanes so
since it has one carbon it is based off
of methane methane though is ch4 as we
will see it might be jumping nice slide
here but we'll just talk about it here
as well but methane is ch4 the problem
with methane though is if I wanted to
put it onto this longest continuous
carbon chain in order for it to attach
as methane you would need to put another
bond right just like
and the problem with that is now you
would have one two three four and five
bonds and if you remember four bonds
it's all carving can have right so
that's too many bonds so when it is a
group in one carbon what we have to do
actually is get rid of one of those
hydrogen's and when we get rid of one of
those hydrogen's we get a ch3 group and
the ch3 group is is good because this
spot right here which in methane is a
hydrogen now is open to bond to say a
carbon and this ch3 part of it which is
an alkyl group in alkyl ends and yl goes
for a methane to a methyl group so we
dropped the last part of methane and we
put yl again to indicate that it's a
group it has one less hydrogen than
methane and that one less hydrogen gives
it a place to be able to connect without
having too many bonds any questions on
that I see it was one slide for that but
yeah that's so that's essentially what
we're talking about here so once we find
that longest continuous carbon chain
again anything that is not part of that
longest continuous carbon chain will
most likely be one of these alkyl groups
which again is just a word that
basically means it's a carbon containing
group and it is a carbon containing
group that basically lacks one hydrogen
and the lack of a hydrogen again gives
it the ability to bind into the longest
continuous carbon chain without having
too many bonds and as you can see just
like we did with the methane we drop the
ane and we put the Y L we had say a two
carbon group again a two carbon group
would be based off of ethane which is
this guy but again the way ethane is
exactly like that it has no way to bond
into a into a chain because it has too
many so we essentially
we'll drop one of the hydrogen's off and
what we'll end up with is something like
this and again missing that hydrogen
there it gives it a place to attach
without having too many bonds and it
goes from ethane to a ethyl group yl at
the end of it and that's what we see
here so pretty simple again based off of
those first 10 alkanes you drop the A&E
you put the yl it also again will have
one less hydrogen again to allow it to
connect in here are some alkyl groups
you have a similar table in your book I
think methyl ethyl this is propyl again
three carbons based off of propane butyl
four carbons based off of butane a
pencil a hexyl and so forth
each of these based off of those first
10 alkanes one less hydrogen to allow it
to bond now there are some groups that
are have special names is sort of
special arrangements and this is
isobutyl sec-butyl t-butyl but this is
probably the common one here this is
what's known as isopropyl group and
isopropyl group looks something like
this and again the
action happens here
and this is was referred to again as the
isopropyl group it may say yourself how
is that different than say a propyl
group which looks like this
you
and really the difference comes from
sort of where it connects now when we
talk about carbons there's a way to
classify carbons and for example if you
have a carbon that's attached to one
other carbon so this guy right here
would be known as a primary carbon are
the one with the little circle on top
and that's basically this carbon right
here that circle is attached directly to
one other carbon can also have a carbon
for example that is attached to two
other carbons and that is what is known
as a secondary carbon and you also could
have a carbon that is attached to three
other carbons so again if we look at
this carbon here it's one carbon there
two carbons there and three carbons
there and this is what is known as a
tertiary carbon and the difference in
sort of where the attachment occurs it
gives us sometimes some different groups
and again the guy on the right here is a
propyl group our normal propyl group and
the attachment that occurs for this
group to say the longest continuous
carbon chain it happens at the primary
carbon again this is a carbon that's
directly attached to one other carbon
while we're here in the isopropyl group
the carbon that's attached to the chain
is this guy which is attached directly
to one and two other carbons and this
would be a secondary carbon so these
sort of attachment places and how they
attach depend on sort of which carbon it
attaches to you will give us some
different group
that occurs and that's why when we look
over here for example this is was those
t-butyl or tert-butyl t-butyl or turk
means tertiary basically and if we look
at the carbon that gets attached it's
attached to one two and three other
carbons and that would be a tertiary
carbon this guy right here is attached
to one and two carbons and again that is
why this is considered a secondary
carbon as well so honestly I you've got
to worry about probably two million on
this slide this guy again though the
isopropyl does come up a lot and it is
sort of a historical scribe the name
that isopropyl group and used and really
kind of named that way a lot as well all
right so let's go through sort of naming
these guys here together and sort of
talk about what we want to do so if we
take this one here that we have on the
screen again the first thing that you
want to do is locate the longest carbon
chain so we got one two three four five
and six
we also by the way could get six if we
went one two three four five and six and
the last option would go one two and
three which is obviously less than six
so again you can't get sort of sometimes
the same number in terms of longest
continuous carbon chain no matter which
way you sort of go I always recommend
though if you have multiple ways to get
to the same number I would probably
choose the straightest sometimes it's
easier to see and that's sort of what
they did here so they put a box around
the longest carbon chain that's usually
a pretty good thing to do again six
carbons is based off of hexane so that
becomes sort of your base of the name
here now when we look at this we also
want to find anything that is attached
to that longest carbon chain but not
part of the group our longest carbon
chain and again this is gonna be our
group
this group again has one carbon which is
based off of methane but because it's a
group it is a methyl group so we have a
methyl group attached to the sex ain't
but like I mentioned before the whole
goal of naming really is about location
so we need to give the location of where
we find that methyl group and to give
the location really you need to number
the longest carbon chain so if we number
the longest carbon chain this is one car
this is 2 this is 3 this is 4 this is 5
and this is 6 now that is one way that
you can number that longest carbon chain
in this case going left to right we also
could number the other way going 1 2 3 4
5 & 6 so those are really two different
ways that you can number the carbons and
going left or going right and what you
want to do basically is give the
location of that methyl group so if I
went the green way my methyl group would
be at 5 and it would be a methyl group
carbon number 5 if I went the purple way
and I wanted to give the location of
that methyl group it would be at carbon
number 2 so one of the important rules
when you're naming alkanes is once you
have the longest continuous carbon chain
you want to number it which ever way
gives the group the smaller number it's
also a smaller number you know so that
is sort of the goal here so you want to
go with the smaller number and in this
case the smaller number for that group
is two so we would use that and this
become too - methyl hexane all kind of
one word the two methyl means that a
carbon number two we find our methyl
group hexane means we have
a chain of six carbons in a row and the
name of this guy again would be two
methyl hexane a couple of little things
when we do name you see a dash that I
put here and between a number and a
letter
we put a dash now if you should have two
numbers they come back to back we put a
comma between those when we need them
and the last thing is when we're naming
these things all the groups go an
alphabetical order so the groups go in
alphabetical order regardless of number
and we do kind of use those little
things so again if you have a number to
a letter we put a dash between it which
is again why this dash is right here
number number here two letter here we
put a dash between it and again two
numbers we do a comma any questions on
that and again this is a good sort of
reminder as well that even though it may
be drawn slightly different when you're
counting those longest carbon chain you
do you want to follow it and every sort
of conceivable pattern so here obviously
one two three four five six again here
one two three and you shouldn't stop
even though you know there's nothing to
the right but it does continue down this
way four five and six and even this guy
the way is drawn one two weeks you go
down three four five you can go back up
or down if you like and you can see in
each case the longest continuous carbon
chain is our six and in each case the
name of all these guys would end up
being the same and be the exact same
things we just did there each of these
guys here would be 2 methyl hexane again
just to show you this is the one we just
did with this longest carbon chain
there's our Gaya carbon 1 & 2 and over
here for example this would be our
methyl group and in this case we would
number this way 1 & 2 so these all would
be 2 methyl hexane even though they look
very different in terms of the way
they're drawing
and that's why again you always want to
sort of go with all your options in
terms of longest continuous carbon chain
to figure out which one it is alright so
we did that we got to naming those
groups by numbering get the idea there
another sort of thing that does happen
like we saw on a previous sort of slide
is sometimes you will have more than one
of the same group in a molecule and we
do use a prefix to indicate that so let
me back it up here and find that one
that's right here so for example again
if we sort of approach this from our our
knowledge right now again let me just
maybe redraw it to make it a little bit
neater here
so if we do this again
no matter which way we go if we go
straight left to right we have three
carbons if you went left and then went
up you also have three if you went right
and you went up you have three if you
went right and you went down you have
three if you went left and you went down
you have three so no matter which way
you go in this guy you will have three
carbons again the straightest is
probably the easiest three carbons again
going to be our propane in terms of our
name now when we look at this kind of
like what we talked about a little bit
earlier attached to this here is a
methyl group here - - here is also a
methyl group so we have two methyl
groups in that compound so two methyl
groups the prefix for two is die so we
have dimethyl would be our groups there
because there's two of the same sera
mean that they has to be on the same
carbon just happens to be in this case
and if we number this left to right is
one two and three are if we go right to
left it's one two and three in this
particular case and it does happen it
really doesn't matter which way you go
if you went left to right those groups
would be a carbon number two if you went
right to left it would be a carbon
number two two is the smallest number
what it's important in this case is you
do have to give the number for each of
the methyl groups even if they are the
same number so that's why we have 2
comma 2 - die-die methyl propane the
first two is for the first methyl group
at carbon number 2 the second two is for
the second methyl group also found a
carbon number two the dimethyl means
that in that molecule there's two methyl
groups again they don't necessarily have
to be at the same carbon for the begin
it dimethyl but we do see what we talked
about as well between two numbers here
we have a comma the
when a number and a letter here again we
have a - so again you will see some
multiple groups in a compound and we do
use those prefixes to help us sort of
name does and again here I guess could
just went forward would have been good
as well here as well if we look at it we
have a methyl group here and a methyl
group here in this case not on the same
carbon but we would use dimethyl for it
so if we were to name this guy again
longest carbon chain they boxed it for
us was just nice so we got one two three
four five and six carbons so again the
base of this name because it's six
carbons would be hexane we obviously
have the two methyl groups so we would
have dimethyl and again we need to give
the location so we want to number this
chain and you do have two ways to number
it so let's take a look here if we go
left to right this is carbon one this is
carbon two this is carbon three carbon
four carbon five and carbon six that
means that group number two and three we
have a group if we went right to left in
terms of the numbering
this would be carbon one this would be
carbon two this would be carbon three
this would be carbon four this would be
carbon five and carbon six and if we
went right to left we would have a
groups at four and five so again when
we're choosing numbering we want to give
the group's the smaller number so in
this case we would not use the green way
of numbering we would want to use the
orange way of numbering which gives
those groups the smaller numbers and
putting that together again we need to
give the location of each of those
methyl groups so that would be two comma
three again a comma between the two
numbers - between number and letter
dimethyl hexane so this would be two
three dimethyl hexane again it's really
all just about location and tells us
basically if we go to carbon number two
and we go to carbon number three we
should find a methyl group on a long
chain of six carbons which is taxing any
questions on that all right so we're
kind of going through I'll just put it
up here so you see it was sort of what
we talked about again we do want to put
everybody together in terms of
alphabetical order in terms of the
groups so again if the groups were
different names like a methyl and ethyl
with the ethyl would come first
ignoring prefixes and also ignoring
numbers you know in terms of lower
number first or some like that so
alphabetical sort of takes the the lead
there and that's gonna give us our two
methyl hexane which we saw earlier and
hopefully we get the same things we just
got here again I'll just put it up here
so you can see it case you want look at
later two three dimethyl hexane again
the location of everybody alright so
let's take a look here once you take a
second and once you give this guy a name
and see what you come up with
you
and we would also have an ethyl group we
do want to number it in a couple of
different ways we could go left to right
which gives us our group numbers as we
see here two five and six but you go
right to left which would give us one
two three four and seven if we go the
other way so putting all that together
in sort of alphabetical order five ethyl
to sixth I methyl octane again to go
through it eight is our longest
continuous carbon chain so that's where
the octane part comes from and we have
two methyl groups again does not have to
be on the same carbon but we do have the
dimethyl and they are at carbon number
two and six and then five ethyl again he
even known number wise this guy is
higher EB four M is what we're looking
at in terms of alphabetical so five
ethyl to six dimethyl again we see a
dash between a number and a letter also
here as well we also see a comma between
two numbers in this case again if we
numbered the other way one two three
four five six and seven so if we went
sort of the opposite way we would have
groups at three four and seven which
again is a larger set of numbers than
two five and six and it's really when
you look at these two numbers here the
two is less than the five the two is
less than three so that's why again we
went the other way
all right so why don't you try these
couple here see what you come up with in
terms of the names and then we'll talk
about it
by the way there were two different ones
there on the bottom
ok let us start going through and seeing
what we're doing let's start with the
top one and again we want to figure out
the longest continuous carbon chain so
if we just do the straight way we got
one two three four five and six now if
we go straight one two three four five
and go upwards six so it looks like six
so far if we go straight one two three
four five so that's less and our last I
think couple of options here I would go
this way one two three four five and six
so and the last last way you could
actually look is one two all orange
three four five and six going that way
so again no matter which way you sort of
go there it looks like we're topping out
at six and so let's go with just
straight six looks good we'll just go
straight across I think right
so we have six carbons and again the
base of 6 is hexane now when we look at
those six sort of longest carbon chain
we also see a couple groups that are
attached so up here we have a two carbon
group two carbon based off of ethane but
because it's a group it's a ethyl group
we also have a one carbon group right
there based off of methane with the loss
of the hydrogen it's a methyl group so
we do need to figure out the numbering
so if I go left to right I got one two
three four five and six so left to right
I have groups at three and five if I
number the opposite way here going one
two three four five and six
I have groups at two and four so again
we want to go with the lower numbering
which is the two and the four so that
means that carbon number two there is a
methyl group so carbon number two
there's a methyl group and a carbon
number four there's an ethyl group now
we do want to put this together an
alphabetical order which means even
though number wise the e will come
before the M here so putting all that
together gonna give us four ethyl two
methyl
and then hexane any questions on that
name there alright so let's take a look
at the guy on left looks like we have
one two three four five six and seven
carbons other option would be right to
left one two three and up was four we
can then go one two three four five and
six if we went up so it does look like
one two three four five six seven is
gonna be our longest continuous carbon
chain again goes down and then goes up
again the basis of seven carbons is
heptane and here we see we have just one
group attached and that would be our
methyl group so what is left is to
figure out which way gives our methyl
group the smaller number if we go this
way that's one two three four and carbon
number five and if we go right to left
one two three four five six and seven so
obviously going right to left gives our
methyl group a number of three left two
right there gives us a five so we do
want to go with step three
so put him out together three methyl
heptane all one word there in that case
any questions on that naming there now
if we look to our guy to the right
there's a lot going on there so let's
see here
if we just go straight across
that is one two three four five six
seven carbons if we go straight across
and then detour up like so that is one
two three four five six seven carbons so
you may say to yourself it looks good
that's more but again you always want to
sort of try all your options so if we
perhaps start up here come down come
across and then go up if we count how
many carbons are in there that is 1 2 3
4 5 6 7 & 8 carbons so again you want to
try all your options as you can see here
not the straightest by any means it does
go down goes back up and all that good
stuff but 8 carbons is our longest
carbon chain which means we are going to
have a base of the name that is based
off of octane we do have in this case
now a couple of different groups
attached we have a two carbon group
right there which is a ethyl group we
have I kind of wrote over it there I'll
Circle it we have a one carbon group
which is a methyl group
so we do want to do some numbering and
in this case we want to make sure again
numbering wise we end up with the
smaller numbers so if I start numbering
up here this would be carbon one carbon
two carbon three carbon four carbon five
carbon six carbon seven and carbon eight
which means if I go kind of the purple
way I have a group at carbon two and
carbon number five the other option
would be to number really the opposite
way and if we number the opposite way
here this over here in orange would be
one two three four five six seven and
eight and again that means that I would
have groups at carbon four and six so
again always the smallest numbering so
we do want to go the purple way here and
that's going to give us a name of well
that's gonna put that's actually carbon
three I'm sorry there we go
it's actually carbon three still works
out the same no it's as good at 3 or 5
so 3 is still lower than 4 which is good
so that would be 3 methyl here and this
would be 5 ethyl again alphabetical the
E's gonna come before the M so this is
gonna be 5 ethyl
- 3 methyl
octane and questions on how to name
those so again you do want to make sure
that when you're doing your options
there you do try to check all the
different combinations again when you're
doing the longest continuous carbon
chain the really key thing is not to go
backwards so you can't back up and go a
different direction you pretty much got
started one direction and go until you
again hit sort of a dead end and you do
want to check all your options as we saw
there in the last one depending on sort
of which option you choose you obviously
you'll get the different number but you
always want to stop with the longest
carbon chain any questions on those
names there
let us we'll just look at the top one
here so this top one here we want to
figure out the longest carbon chain we
have one two three four five six seven
if it goes straight across we have one
two three four five six seven there you
go kind of down and across we have one
two three or five six seven if you go
that way
and I think that's all your options kind
of one two three four five six so it
does look like seven is pretty much the
longest no matter which way you go so if
you do have that option again it's
sometimes easier to see everything if
you just take the straightest so if you
do have about options so if we just go
straight across here again one two three
four five six seven so the base of our
name is going to be heptane again here
we have a methyl group over here
I also have a methyl group over here and
we have a two carbon group over here
which is a ethyl group so in terms of
numbering and names we do have dimethyl
as part of the name because we have two
methyl groups in the compound we also
have an ethyl group so we do want to do
some numbering so let's take a look at
the numbering options here
going left to right that's 1 that is 2
that is 3 that is 4 that is 5 that is 6
that is 7 that means going that way we
have a group at - I'm gonna count right
hopefully this time 3 and 5 we go the
opposite way
going right to left we have 1 2 3 4 5 6
and 7 so going right to left we have a
group at looks like 3 5 and 6 so again 3
being bigger than 2 going to be too
large so we would want to go with the
left to right numbering are the blue
numbering so if we do that we will then
get we have the methyls at carbon number
2 and 3 so again 2 comma 3 dimethyl our
ethyl group would be a carbon number 5
so again II before M here so the name
here putting all that together let's go
down here I think we will go with 5
ethyl - 2 comma 3 dimethyl and heptane
and questions on the naming of that
there okay let's get that let's also
talk about though if you do have the
name and you'd want to draw the actual
formula for it how you go about doing
that so if you're given the name you
want to all the form a truth be told it
is actually the easier of the two I
think to do because pretty much they
tell you everything whenever you have
the name and you want to draw the
formula you always approach it the best
approach is starting at the back of the
name and heading in that direction and
that's because the back of the name
basically gives you how many carbons you
should deal with so when we see the name
butane butane is four carbons which
means what you want to start with is
really just the carbons in this case so
leave yourself a little bit of room get
your minds to feel some stuff in they
just want to start with the four carbons
which takes care really of the butane
part we then have dimethyl so we know
methyl is a ch3 and dye means that we do
have two of them and what that means is
that is what the numbers here here right
so we have a methyl group at carbon
number two and we have a methyl group at
carbon number three the nice thing is
since you are drawing it you could
choose whichever way you want to go so
you could go left to right and call the
guy on the Left carbon number one you
could also if you wanted to start on the
right hand side and go right to left and
call that guy carbon number one I'm
gonna go left left to right so I'm going
to call this guy right here carbon
number one so that means that carbon
number one then to the right would be
carbon number two I would have a methyl
group so I would draw that in again it
doesn't matter if you drew it up or if
you drew it down it's all the same and
this is carbon one on the left this guy
would be carbon two that means that
carbon number three I would also have a
methyl group that is there and that
takes care of this part of the name so
what is left to put in there is
basically hydrogen's yeah
so what you're gonna put in at the end
is hydrogen's again remembering the big
key thing that carbon wants for bonds
and so when we look at the guy on the
left it has only one bond coming in
which means in these three more bonds
and those three more bonds would come
from hydrogen so we've put three
hydrogen's the carbon right here at
carbon number two has one line coming in
there two lines coming in there three
lines coming in here which means it has
three bonds so it only needs one
hydrogen same thing the guy over here on
the right one coming in two coming in
three coming in just needs one bond and
one hydrogen the guy at the end has only
one line coming in he needs three
hydrogen's
this would be your condensed formula for
this guy so when you're given the name
is again sometimes very easy or a lot
easier to do because you basically just
need to draw what it says so with that
in mind watch you try the next two and
then we'll talk about it again work from
the back from right hand side to the
left of the name
okay let us take a look and to answer
your question we will not be having a
quiz obviously since finals are next
week but this stuff will be fair game
for the final so I the final will cover
everything okay so when we're looking at
this again we want to work backwards so
heptane means seven carbons so we'll
draw it sort of like this one two three
four five six and seven one two three
four five six seven so seven takes care
of heptane part now Ethel means that
carbon number three we have an ethyl
group again that's going to be a two
carbon group which will be our ethical
and a carbon number two we have a methyl
which is our one carbon group so just
like before since you're drawing it you
could go left to right and call the guy
on the Left carbon number one or you
could go on the right and call it carbon
number one you just can't change your
mind so whichever way you choose you
have to stick with it so I'm gonna go
left to right so the guy on the left
here for me is gonna be carbon number
one which means that carbon number two I
have a methyl group so I'll draw my
methyl group in takes care of that
carbon number three which is right next
door is where our ethyl group would be
and that would take care of that and now
again everything else is gonna be
hydrogen's until carbon has four bonds
so guy at the end these three guy right
here has three coming in I only needs
one hydrogen same thing with the guy on
the right guy on the next to those guys
has two lines coming in which means he
needs two hydrogen's to get the four
next one no so needs two hydrogen's next
one needs two hydrogen's and lastly I at
the end that has only one line coming in
needs three hydrogen's any questions on
that one there and looking at the last
one here again working backwards so
pentane gonna be five carbons
so that's what you want to start with is
five carbons takes care the pentane part
again a carbon number four there's a
methyl group which is a ch3 and now
carbon number two there's a chloral
group so we haven't seen klorel chloral
is a halogen and it is CL group number
seven so group number seven those
halogens they do appear in a lot of
organic molecules and their name kind of
like this so chlorine would become
chloral if you had a bromine it would be
a bromo if you had a fluorine it would
be a floral and if you had in iodine it
would be an iota so that sounded kind of
weird one like iodine but chloro bromo
if you had a bromine attached so those
are sort of have those guys are named so
works kind of same way again I'm gonna
go left to right and then my gun laps
gonna be carbon number one so right next
door would be carbon number two which is
where I would put the chlorine that
means that this guy right here is carbon
number three and carbon number four
would be here and same deal we're gonna
fill in our hydrogen so he needs three
this guy needs one this one needs two
this one needs one and this guy at the
end needs three so like I said I think
kind of going on name too formal is
actually the easier of the two because
they pretty much tell you where to draw
everything where everything is
I think questions on how to name or draw
these sort of formulas yeah so the idea
what the hydrogen's is when you're doing
this so the question is uh how do you
find out how many hydrogen's and it's
based off of this idea up here that
carbon pretty much needs four bonds so
if we just kind of back up where we just
were
get rid of all this guy here we'll just
redraw this guy up here so right before
we finish that last guy we were at this
stage where we put everything on so we
had something that looked like this
okay so when we're trying to figure out
at this point after you pretty much put
everybody on there so we've got rid of
this guy we got rid of this guy you know
we put everything on there the only
thing that's left at this point would be
the hydrogens and the goal was to get
carbon to have four BOTS so the guy on
the left at this point only has this
bond coming in I'll make a really big
it's a single bond still but this guy
come in only has one bond which means he
needs really three more hydrogen's to
get him to four and that's why we put
ch3 and that's because if I just draw
that part out really what he had was
something looks like this so by putting
those three hydrogen's there it would
look something like this if you drew out
that guy and that gives this carbon here
on two three and four bonds which is
what it needs so we're kind of filling
in all the rest of it with the number of
hydrogen's to get us before we go to guy
next to him we have one bond here again
this big bond here is to this guy coming
in is three bonds to that high carbon
that means he just needs one more
hydrogen to bond in to get to four if we
come to the guy next to him it has one
bond here two bonds on this side he's
missing actually two more bonds and
again that's gonna be filled by two
hydrogen's and again if I drew that guy
out he would then look like this and
that's why we again we need those two
hydrogen's to get us to four and if we
continue that powder and one bond here
two bonds here three bonds here so he
needs one more hydrogen and the guy at
the end only has one bond so he needs
those three hydrogen's he's just like
the guy on the left hand side so that's
again basically the goal here is to get
carbon to those four bonds and basically
we fill it in with the hydrogen's other
questions on
okay alright so we're gonna kind of go
through that so it's just talking about
cycloalkanes so we talked I think about
him a little bit before but cycloalkanes
are really alkanes where we kind of
joined the ends together if you will and
by joining the ends together they
actually do lose those two hydrogen's
like we talked about last time and
cycloalkanes have the C and H to end
formula again they're missing that plus
two part because they close in on each
other and they have two less hydrogen's
here's a triangle a square a lot of
times they are drawn in that line
formula and remember in the line formula
you know everywhere they're sort of an
end of a line are a point if you will is
considered a carbon so again this is the
same as this guy over here the triangle
and cycloalkanes are named the same way
it basically has three carbons which is
based off of propane and because it's a
sort of ring structure we put the cyclo
in front of it so this is cyclo propane
all one word this is four carbons which
is butane also in a ring structure so we
put the cyclo in front of it and it
becomes cyclo butane
there's cyclopentane which is a five
carbon ring cyclohexane again one two
three four five and six carbons in a
ring structure and again as we talked
about in line structure typically don't
put much in there other than the lines
but again at each of these points there
is a carbon that's attached base art
that's there and along with the
appropriate number of hydrogen's so how
do we name this we essentially we'll
just put cyclo in front of it if there
is something attached we basically kind
of do it the same approach so in this
case the big ring here it's kind of
colored in is the base of our name so
this is gonna be cyclohexane again it is
one two three four five and six carbons
together which is where the hexane part
comes in the cyclo because it's a ring
just like the other thing we do have
some groups attached we have a methyl
group and we do have a ethyl group here
now we do want a number this chain as
well to give the locations and we want
to go with the smallest number so if we
start here this is carbon one two and
three that would give us groups at one
at three we go the other way you may be
saying if I go one two and three I end
up with also one and three so that's
sort of a tie no matter which way you go
in terms of numbering between those
groups at the carbons but what's
important as we talked about in terms of
the groups is alphabetical order which
means technically speaking he is gonna
come before em which means we want to
give that guy with the e the lower
number which means we would want to go
this way here when we're number in it
because that's gonna give alphabetically
the group with the alphabetical priority
the lower number and that would give us
if we put it all together the same sort
of way one ethyl three methyl cyclo
hexane
so still alphabetical order and in this
case when you do have a tie you sort of
want to go to the next important thing
which again is alphabetical in this case
and given that Ethel the smaller number
any questions on that now if you just
had
something like
where there's just one group attached
the the ring here would be cyclo propane
because it's three carbons now in this
case there's just one group attached and
because there's just one a group
attached is thought of always going to
be carbon number one where that's
attached and you actually don't need the
number so this would just be methyl
cyclo propane because there's only one
group attached so wherever that group is
attached just gonna be considered a
carbon number one when you have multiple
groups attached like we do here you do
have to give the number so that's why we
gave the number and the guy on the
bottom but the guy on the top does not
necessarily need the number or doesn't
really need the number because there's
only one group attached and again
wherever that group would be would be
considered carbon number one this is
what sometimes referred to as being mono
substituted means one group attached
it's got in the bottom die substituted
which means there's two groups attached
and that's what we see here again in
each of these here we just have one
group attached so that's a methyl group
and this is a six carbon ring which
would be cyclohexane
so that's methylcyclohexane here is a
long group of four carbons and that's
butyl group and this would be
cyclopentane again no number here
because there's just one group attached
so you don't need the number only any
numbers again when there's multiple
groups attached and that's what we did
here in this case this particular one
here we would want to go 1 3 and it
doesn't really matter which way you go
on this particular one because both
groups attach our methyl groups the only
thing you would not want to do is like
number this way 1 2 3 4 5 6 and again
this is why it says not 1 5 because
obviously that's a much larger number if
you went that way so we would want to go
clockwise in this case
given us one and three we still have
dimethyl because there's two methyl
groups in it and again we do have
numbering because there's more than one
group attached now what's a guy we just
did I think all right so let us just
talk a little bit about properties to
finish up here just to make sure we sort
of covered that part of it
alkanes are nonpolar and basically
alkanes are all carbon-carbon bonds and
carbon hydrogen bonds so those are
nonpolar bonds and they're going to use
those dispersion forces as their main
sort of source and that means that
they're not soluble in water because
it's like dissolves like so organic guys
typically will not be soluble in water
so if you put an organic guy in with
like water in a test-tube you will see
different layers you see the organic
layers on top as it's less dense the
water layer if you will is on the bottom
and they will not basically mix with
each other and for example oil is pretty
much all organic carbon carbons long
chains of carbons attached to carbons
and hydrogen's and if you ever seen an
oil spill usually will just float on the
water and again organic guys like out
cans being nonpolar
that also means because they're only
using those dispersion forces they
typically have very low melting points
and boiling points because they don't
have a very strong intermolecular force
like we talked about with a hydrogen
bonding or dipole-dipole interaction so
here you can see in terms of boiling
point they all use dispersion forces the
highest boiling point here in terms of
all these alkanes is the guy with more
carbons and if you remember when we
talked about intermolecular forces the
more molar mass there is they're more
carbons or is the stronger the
dispersion forces that you will get so
in comparison of alkanes the one that is
larger in terms of molar mass would have
more electrons in a higher boiling point
but they have a much lower boiling point
than other organic groups as well and in
term
reactions typically organic guys will go
through a combustion reaction and a
combustion reaction the traditional
organic combustion reaction looks
something like this but it basically is
an organic guy plus some o2 and it makes
co2 Plus water and that is your typical
combustion reaction remember in a
combustion reaction we talked about in
that chapter your typical products are
always co2 and water and oxygen involved
and with an organic guy that's like when
you light a Bunsen burner the gas comes
out they're very flammable right and
you'll get this combustion reaction
obviously we releases a lot of energy
like when you do a Bunsen burner
combustion engine right you know those
things give off a lot of energy as well
so here's another example of combustion
reaction again methane co2 we see CO and
h2o this is what is sometimes referred
to as an incomplete combustion so in a
combustion reaction we typically always
get co2 and water if somebody ever says
it's an incomplete combustion the only
difference is you get carbon monoxide
instead of co2 alright so I think that
is good I think we're gonna call it a
day I got one more slide I guess we
could look at this light real quick I
guess but basically the other type of
reaction that occurs with an alkane is
what is known as a halogenation reaction
and this was known as a substitution
reaction and basically what happens in a
substitution reaction is as we could
kind of see in this picture here one of
the hydrogen's come off and this is BR 2
which is basically to be ours and one of
these BRS goes in or on I guess so in a
substitution reaction with an alkane
which is really what happens basically
you take off a hydrogen you can actually
take off any hydrogen you want and it
gets replaced with one of the halogens
so if you had something like this
and you added it to be r2 which is this
again you could choose any hydrogen you
want you're just gonna take it off and
one of these guys are gonna come on in
this place and really nothing else
changes so you could draw it exactly the
way it looked before so if I just draw
it really quick here just exactly the
way it looked the only difference is the
hydrogen that comes off gets replaced by
the bromine that comes in and if you
think about what came off you have a
hydrogen that came off and you have a
bromine and basically what those guys
will come together will give you hbr so
that's the last sort of thing just to
kind of finish off this slide here and
I'll get your question here in just a
second the hydrogen the bromine will
come together to make HBR all right any
questions on that all right so that that
does officially end chem 2A in terms
of lectures congratulations should be
proud of yourself for hanging in there
and continue to come and participate
under these sort of these circumstances
that we had a couple reminders and again
I'll get to your question which is where
we're going to talk about here our final
is on Monday and it is once the eight
o'clock is scheduled and that's when you
probably should take it again so you
don't run into any sort of conflicts
with any other classes that you may be
taking so it will start at a 8 for
you to take it it will cover all the
chapters that we talked about so
everything including through what we
talked about today it's all sort of fair
game so there's a lot of material but
you just want to kind of think about
other exams the stuff that we took in
sort of the topics when you think back
on those sort of the big topics you know
things like nomenclature things like
stoichiometry conversions obviously gas
laws you know those type of things we
think back oh you know it's kind of
important topics they probably will come
back again
I'm not going to focus on any particular
chapter in particular any more than any
other chapter so I honestly haven't
written it yet so it will probably be
usually will end up being fairly I don't
want to see perfectly spread out but you
know it will be pretty comprehensive in
terms of everything that we talked about
this semester you know it won't be like
perfect but it will be pretty evenly
overall the topic so again I'm not gonna
focus more say on this chapter versus
the other or anything like that
I first off any questions on the final
before I get to your question there
again I honestly don't know truth who I
haven't written yours
I got one tomorrow I'm gonna start with
that one first that's if that's alright so I
really haven't written yours yet so I
don't know it may be similar to a
regular exam maybe have a few more
questions but truthfully I haven't
really written it or anything like that
yeah so again you do want to start
reviewing all that stuff from way back
when I don't remember when we started
the semester anymore but you know all
that stuff that we did talk about so you
want to review all those things and
again you should want to think about
obviously is a lot of material so you
want to think it when you think back on
things or you look at chapters you think
oh this chapter you know this was sort
of the main kind of big stuff that we
talked about in terms of maybe
calculations or stuff like that so those
are the things you want to kind of look
at now in terms of your question about
the homework I did sort of make a
mistake in that sense when I pulled it
over for sampling I forgot I did extend
the due dates on those homework
assignments so obviously you still have
the opportunity to do those homework
assignments and when you do those
homework assignments obviously in the
end it would be updated in terms of in
terms of those grades I just remind them
over because I take it from sampling
kind of by hand and move them over I did
sort of forget I think I did extend
those so you still have the time to do
those assignments if you have not
completed them and in the end those
those points will be readjusted
obviously accordingly so that should
answer that yeah and well I might do I
was go I'll take them maybe those scores
they don't offer good canvas for now but
that does sort of do yeah I like when I
pulled them over I just I sort of I was
thinking in my head we were a took the
sort of exam on that but I forgot I did
extend them so you still definitely have
time for that also remember there if
there might be another assignment or two
up there that you need to complete as
well so make sure that you do make sure
that you do finish all that online
homework you know obviously by the due
date and like I said even if it reflects
now zero and it's one of those
assignments that hasn't been due yet it
will be changed for sure at the end now
in terms of grades and all that I've
gotten some emails us up on that just so
we're all clear we are still going with
whatever it said on the on the syllabus
in terms of grades and grade breakdown
and anything that you're allowed to do
so again whatever it says on the
syllabus is what
going to be following and just off the top
of my head so again refer to the
syllabus for specifics because I teach
five classes but off the top of my head
I believe you'll get to opportunity I
think drop your lowest quiz if I'm not
mistaken and I believe you'll also have
the opportunity if it does say so on the
syllabus which I think it does that if
your final is again a higher score than
perhaps one of your exams you'll get to
replace that as well with your final
score your lowest exam so again I
believe that's what it says on the
syllabus and if it does say that that is
again we're still following obviously
whatever is posted right now has not
been adjusted or anything like that so
you know what you're looking at probably
right now would be I guess your worst
case scenario your real grade it's
probably a little bit higher than what
you see right now again after those
adjustments are made and they're not
going to be made obviously until the
very end because it's just a pain to do
so I can't adjust and readjust and stuff
like that so what you see now is sort of
like your raw score up there and all
that and you know it probably will be a
little bit different but whatever it
says on the syllabus in terms of grade
breakdown and what you get to do in
terms of dropping or replacing we will
still do that all right any other
questions on anything like that so again
congratulations on finishing here you
still have one more thing to do
obviously the final make sure you can
take care of all that homework I enjoyed
having everybody in the class when I was
able to see you in person and online as
well and I do thank you for continuing
to show up and attending lecture and
stuff like that I wish you the best of
luck on our final and all the rest of
your finals and everything like that and
again if you do have any questions
between now obviously a Monday you know
you're welcome to email me and
everything like that all right all right
with that I guess we will officially end
the last lecture of the season here
again congratulations have a good rest
of your day a good summer and all that
good stuff and you know if you need
anything feel free to email me have a
good one
you
