GCSE Chemistry: Monomers and Polymers
Hey everyone and welcome to this video on monomers and polymers there are thousands of different polymers in our world like naturally occurring polymers that you can find in your food and bodies there's also synthetic polymers that some of your clothes are probably made of.
To understand more about polymers we'll define what a monomer is and also what a polymer is then we'll look at how we represent polymers and finally discuss some of the properties and bonding of polymers so let's get started so first of all what are monomers and polymers i know this is chemistry.
But let's take a real quick greek lesson if we break down the word monomer into two parts we get mono which means one and mer which means part so a monomer is one part or a single structural unit of a much larger molecule called a polymer.
Breaking down the word polymer in the same way we get poly which means many and mer which still means parts so if we put this together in one definition polymers are large molecules made up of many repeating units of a small molecule called a monomer okay.
So to make this a little clearer imagine a chain and each individual link is one monomer it's one part of the giant chain that we're going to end up with let's say the monomer is a molecule of ethene which is an alkene because it has a carbon-carbon double bond.
Alkenes are common monomers used to make polymers because of this double bond when we join a bunch of these monomers together we get a long chain of ethene molecules which we call polythene you might not realize it but you've probably come across polythene before it's one of the most common plastics in.
The world used to make up things like plastic bags and bottles overall this chain analogy should highlight that polymers involve many many tiny monomers combining together over and over to make a really large polymer what we've ended up with is a really long chain of carbon molecules all.
Strung together the reason we have so many different polymers in our world is because we can make polymers using different monomers for example when we use the monomer propene instead of ethene we get different kinds of linkages which results in a different polymer so now that we understand polymers are.
Incredibly large molecules we can look at how we represent polymers they're so large that if we drew them out we'd be writing forever so there's a way we represent polymers using their monomers let's continue to use ethene as an example of a monomer we know that polythene is just heaps of.
Ethene molecules that go on and on so in order to write this we draw brackets around the monomer the double bond of the alkene actually breaks when it becomes part of the polymer so that it can bond to other monomers to form the chain so in this case we draw the monomer with.
The carbon-carbon single bond then the two single bonds which extend outside the brackets indicates that more monomers can join over and over for the polymer the n in the bottom right corner indicates how many times this monomer repeats itself in the polymer for example this could be 500 and this.
Would mean that there are 500 euthene monomers making up this particular polyphene polymer note that the number of monomers which make up a polymer often isn't fixed instead the precise number varies depending on the situation however the specifics of a particular.
Polymer is not the key point here the takeaway is that we represent polymers using their monomers so now that we know about polymers and how we represent them let's study some of the properties of polymers the fact that they're really long molecules gives them most of their distinctive.
Properties there is some variation in the properties of polymers due to the unique structures and monomers of each polymer but overall most polymers have very strong covalent bonds joining them together being incredibly long there are strong forces of attraction between polymers.
This is because longer molecules have greater intermolecular forces for reasons we don't need to get into just remember that being large molecules with a high molecular mass gives polymers relatively strong intermolecular forces so these strong intermolecular forces.
Mean that polymers are often solids at room temperature this is because these strong intermolecular forces would require lots of heat energy to be broken and so polymers often have to be heated to turn from a solid to a liquid this means that they're generally quite strong rigid and hard substances.
Of course there are some variations and exceptions to this but on the whole plastic polymers are a good example of how polymers are rigid and hard substances and all right that's the end of this video we've defined a monomer as a single structural unit of a much larger molecule called a polymer.
Meanwhile polymers are large molecules made up of many repeating units of a small molecule called a monomer we represent polymers by drawing brackets around the monomer and indicating how many times it repeats in the polymer finally we talked about how polymers generally have strong intermolecular.
Forces so they're generally solid strong and rigid at room temperature but there are some exceptions but that's all we've got time for today i'll see you next time you