Isomers | Properties of carbon | Biology | Khan Academy
0 (0 Likes / 0 Dislikes)
many times in chemistry will see
different molecules
that have the same constituent atoms for
example these two molecules here
they both have four carbons 1234
1234 so far right their chemical formula
BCE for and then they both have
123 456 789 10
123 456 789 10 hydrogens
so both love them both of them have the
chemical formula
c4 each 10 c4 h10
but they're still fundamentally
different molecules and you can see that
because they have different bonding
for example over here we have a carbon
that is bonded to three other carbon and
hydrogen
or rear can't find any carbon that's my
2 three other car but I can find one
that about two two other carbons but not
one that bond at three other carbons
so how we've put the atoms together is
actually different they're bonded
two different things and so when we have
the situation where you had the same
constituent atoms we had the same
chemical formula
but you're still dealing with different
different molecules because a
either what their how their how their
bonds are made
or how they're what their shape is we
call those
isomers so isomer isomer
you have the same chemical formula
the chemical formula
formula but you could have different
bonding
but different different
bonding bonding
or shape bonding shape
or orientation corriente Asian
so over here you have just different
bonding in this type of isomers called a
structural isomer
so these characters are structural
isomers team constituent atoms
but different bonding structural isomers
so that structural isomers right right
over there
now when you look at this pair this
period the way those look like
structural isomers only had the same
constituent
both of these for example have four
carbons four carbons
today both at 12 345 sick
123 for 5678 and they both have
8 hydrogens so we could both these are
both see
for each 8 a jade
it looks like they're bonded similarly
for example I mean though the left-hand
side here these
look identical on the right hand side
you have a carbon bonded to another car
been at that spot at three hundred and
carbon bonded to another carbon
responded to three hundred in Skyrim
bonded to hydrogen carbon by did bonded
to hire did
so looks like the struck the the bonding
that everything is bonded to the same
things
but you might notice a difference over
here on
the right hand side this ch3 is on the
bottom right
well over here to on the its on the
top right and went okay well we know
what's the big deal there these you know
all these molecules are all moving
around maybe they're rotating with
respect to each other
and these things could disk thing could
have rotated down to become what we have
appear
if this was a single bond a Cinnabon
would allow for that type of rotation
it would allow for these things to
rotate around each other for the think
the model to rotate around that bond
but a double bond it does not allow that
rotation
so this fixes these two things this
fixes
these two things in place and because of
that
these are actually two different
molecules over here on the top
you have the CH three groups they're
both they're both
on they're both I guess you could say
facing down or the both on the same side
love the double bond well over here
they're on different sides
they are on different sides the double
bond
and so this type love isomer -ism where
you have
the same positions and you know the same
bonding this is called
diário isomerism so we're here we're
carrying much more about how things
sit in three dimensions now we don't
just care about what's bonded to water
the constituents
actually this one is we'll see this is
also steer I summer because with this
does carbon is bonded to the same things
in either case
so these are both these are both
situations these are both sterio isomers
sterio sterio isomers
and this particular view
creation to steer isomers called assist
transacted summer
sis is when you have the two groups on
the same side
sis and transit when you have the two
groups on the opposite sides of the
double bond
sis trans isomers sis
trends isomers
isomers and these are often called a
geometric isomers
geo metric geometric
isomers so that a subset so when I
what's the strands are geometric I'm
talking about these two characters a
year
they are a subset love sterio isomers
now what's going on over you have no
double bond I'm not talking about sis
and trans
a carbon as I just said is by the
fluorine chlorine bromine and hydrogen
chlorine bromine chlorine and hydrogen
Howard these two things different
and though the way that they're
different is if you were actually tried
to superimpose them
on each other you'll see that it is
impossible they are mirror images of
each other
because it's four different constituency
you can actually not you cannot
superimpose
this molecule onto this molecule over
here and actually because %uh that
they actually have different chemical
properties and so this over here these
these two characters which is a subset
sterio isomers
cirrus rumors are concerned with how
things are are are positioned in three
dimensions not just
there the how their body is different
but this subset where you have these
mirror images that cannot be
superimposed
we call these and then Shurmur's so
these two characters
these are financial MERS nan schumer's
and an end show comes from Greek the
Greek word or the recruit opposite
so these are opposites of each other and
they cannot be super oppose the mirror
their mirror images so all these are
different variations love
isomers and once again you might okay
these are clearly two different
molecules I have different bonding
but even sis trans isomers will have a
different molecular
will have different chemical properties
these two in particular they aren't that
different but they do have different
chemical properties but sometimes
they're so different that one might be
able to exist in a biological system
while the other is not one might be okay
for your health and the other might not
be okay for your help
same thing for an answer MERS 1
might be biologically active in a
certain way and the other one might not
be about Jack Bauer biologically active
in that same way