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- Let's say we have some chloroethene here, and you
- wouldn't have to call this 1-chloro-eth-1-ene, because if
- you just go with chloroethene, there's only
- one way to draw this.
- And the common name for
- chloroethene is vinyl chloride.
- So let's say we have a bunch of chloroethene molecules
- along with or mixed with some hydrogen chloride.
- And I've drawn all of the valence electrons for the
- chlorine atom and I've drawn a little magenta electron, the
- one that the hydrogen atom brought to the table.
- So we've seen something like this before.
- What is likely to happen?
- Well, maybe one of these carbons is willing to give up
- an electron.
- That electron goes to the hydrogen because this electron
- is already being hogged by the chlorine, so this hydrogen has
- a partially positive charge.
- Chlorine has a partially negative charge, so that
- electron would be attracted to the hydrogen.
- Then this electron can be completely
- hogged by the chlorine.
- And if we had to decide which of these carbons is more
- likely to give up the electron, you just have to say
- which one is bonded to things that it can share electrons a
- little bit with.
- This carbon is only bonded to hydrogens, so it's already
- hogging their one electron each, and there are no more
- electrons to share with it.
- This guy is bonded to a chlorine, so the chlorine has
- a bunch of valence electrons.
- It might be able share a little bit with this carbon if
- this guy became a carbocation.
- So this guy will lose an electron.
- This carbon will form the bond with that hydrogen.
- So let's draw it out.
- So let's say this carbon's electron is that blue thing
- right there.
- Well, we could draw it like this.
- It goes to the hydrogen, and then the hydrogen's magenta
- electron goes to the chlorine.
- This is just a plausible mechanism.
- Now, once that happens, what will our setup look like?
- What will it look like?
- It will have this carbon over here bonded to two hydrogens.
- It has its single bond to that other carbon that just lost
- its electron, which is bonded to a hydrogen and a chlorine.
- And now this carbon on the left, it is now
- bonded to the hydrogen.
- That electron went to the hydrogen and it formed a bond
- with it, so then it forms a bond.
- So that little blue electron is at this end of the-- I want
- to make it blue.
- That little blue electron is at this end of the bond, and
- it is now the hydrogen's electron.
- And that magenta electron went to the chlorine, so now it is
- a negative ion.
- It is a chloride ion.
- So we have a chloride ion.
- It has its standard seven valence electrons that it
- started off with, but now it took that magenta electron
- from the hydrogen, and so now it has
- eight valence electrons.
- It gained an electron.
- It now has a negative charge.
- This guy over here lost an electron.
- He now has a positive charge.
- Now, the next thing that you might expect to happen, if we
- just followed the pattern of the last several videos, is
- you would say, hey, this guy will now take an electron from
- the chlorine, which is-- or the chloride anion, I should
- say, which is completely plausible, but there's also a
- bunch of the chloroethane.
- This isn't the only molecule of chloroethene.
- I should say chloroethene, not chloroethane.
- Chloroethene sitting around.
- So let's let us throw another one of those in there.
- So we have more molecules of this.
- So he could take an electron from this chloride ion, or he
- could take an electron from this guy over here.
- Remember, this guy, just like this guy, who was this guy,
- this guy is OK.
- It doesn't require a super amount of energy to make this
- guy lose his electron.
- He's bonded to other things that are willing to share with
- him a little bit.
- Maybe he's willing to lose his electron as opposed to the
- chloride ion.
- So this guy has-- let me draw it in-- so this end of this
- bond is green.
- And then this goes and bonds with this carbon.
- So this will be a long bond right here.
- So this goes and bonds with that carbon, essentially
- giving that electron to that carbon.
- And then what will our setup look like?
- So after that happens, we'll look like this.
- I probably should have copied and pasted this
- from the get go.
- Actually, let me do that before I-- let me copy and
- paste this.
- So now let me just draw, copy and paste this whole thing.
- Nope, that's not what I wanted to do.
- Let me select it again.
- All right.
- Copy and then paste.
- There you go.
- So then we have that thing.
- And let me redraw what I had erased, so that I
- could copy and paste.
- And then we have this guy went over to this carbocation, so
- he's no longer a carbocation, so let me erase this, because
- now he's gained an electron.
- He gained that green electron right there.
- He gained that green electron.
- I'll just draw it right there.
- And now he's formed a bond with this carbon.
- And I'll make it blue, just so we know which carbon we're
- talking about.
- He's formed a bond.
- This bond now moved over to that carbon because the
- electron went with it.
- So now that bond is to this carbon right here.
- That carbon right over there, which is bonded to two
- hydrogens, and now has a single bond to the electron
- that gave up the carbon, has a single bond to that character
- right over here, who is bonded to a hydrogen and a chlorine.
- And since he now lost an electron, he now has a
- positive charge.
- So if you look at this setup right here, it looks very
- similar to this setup, although we've added one more
- vinyl chloride to the mix.
- And the one that we added lost its electron, or this carbon
- lost it electron, and now it's a carbocation.
- So what could happen next?
- Well, we have more of this vinyl chloride sitting around.
- Let me draw another vinyl chloride.
- So I have a carbon, a hydrogen, a hydrogen, and then
- it is double bonded to a carbon, a
- hydrogen, and a chlorine.
- And let me copy and paste this.
- I think you see where this might be going, how this could
- keep on going and going and going.
- So copy.
- Well, I just copy that for now.
- So what's going to happen now?
- This guy could go and give an electron to this guy and form
- a bond, or we could have the same process happen over and
- over and over again.
- Let me get my pen tool going.
- So this electron could be given to this carbocation
- right there.
- And then what happens?
- Well, if that happens, then we're going to get-- I'll move
- to the left now.
- We have our original molecule.
- I'm going to run out of space soon.
- We have this original molecule, and now this guy has
- bonded to that.
- So this carbon right here is going to be this carbon, and
- now it is bonded to this guy.
- That orange electron is now given to
- this guy who was positive.
- So he now has-- let me make it a little bit neater.
- I can do a better job than that.
- So the carbon's here.
- The bond goes to this guy.
- He now has the orange electron.
- He no longer has a positive charge.
- He's got all of his valence electrons now.
- And now this guy is bonded to two hydrogens.
- That guy is bonded to two hydrogens.
- And he has a single bond, this single bond right here to the
- carbon that just lost his electron, who's bonded to a
- hydrogen and a chlorine.
- And because he lost his electron, he now is the
- carbocation.
- He is now a carbocation.
- So I think you see where we're going.
- We can just keep adding and adding and adding to this
- chain of vinyl chloride.
- So if this process just went on and on and on, we could
- make it like this.
- It would look something like this.
- Let me see how well I can draw it.
- So it would look like this.
- So this is a CH3.
- So I'll just draw it as H3C, and then this is bonded to a
- carbon, that is bonded to a-- well, maybe I'll call it a CH,
- which is bonded to a chlorine.
- So we're that far in the molecule.
- And then we have-- let's see the part that repeats.
- This part right here is going to keep repeating.
- That part right there is going to keep repeating, and I'm
- going to do it like this.
- So I'm just going to draw one of them, so you have a CH2.
- That's that right there, connected to a CH, which is
- that right there, which is connected to a chlorine.
- And so that part right there will keep repeating.
- And then maybe the very last one, so you have this guy
- right here, but maybe the very last one that joins on-- I
- mean, this can happen millions of times.
- I just it made it happen two or three times.
- It could happen millions of times and form a super long
- chain or a polymer.
- And what we are describing in this video is actually a
- polymer that you have probably dealt with at some
- point in your life.
- In fact, I guarantee there's some of it in
- your house right now.
- So then we'd have that part right there.
- And we could just make that as CH2, CH, Cl.
- And now, the way we've drawn it, it's a carbocation, but
- maybe we've run out of all of the vinyl chloride molecules,
- or we could also call them chloroethene molecules.
- And now finally, when everything is said and done,
- this last guy, since he's run out of vinyl chloride
- molecules to take their electrons from, he now finally
- takes it from the chlorine.
- So you can imagine this happens many, many times.
- So this repeats many times.
- After this repeats many times, then finally, one of these
- electrons from the chlorine go to that final carbocation,
- because they've run out of other vinyl chlorides, and
- then he attaches right over here to the chlorine.
- Now, this is called-- so when we say that this might happen
- many times, you might write an N here, just to show that it
- repeats many, many times.
- If you know how many times it repeats, if you know that
- there were a thousand molecules here, you would
- write a thousand repetitions, but this is called a polymer.
- And the name for this molecule right here is-- each of these
- units is vinyl chloride, right?
- Vinyl chloride.
- I guess the official name is chloroethene, but the typical
- name, the one people actually to use, is vinyl chloride.
- That's for each of these units.
- It's a polymer.
- We have many of them, so we'll put a poly- in front of it.
- So this molecule right here is polyvinyl chloride, or, and
- now I think it'll ring a bell, or PVC for short.
- And you've probably heard of PVC piping.
- It's what most people have for their plumbing.
- It's those plastic pipes.
- And that's what it is.
- It's polyvinyl chloride.