Low Denisity Polyethene - a polymer made from the Ethene monomer with a higher/more dense amount of ethene molecules (high density).
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What is HDPE?
High Density Polyethene - a polymer made from the Ethene monomer with a smaller/less dense amount of ethene molecules (low density).
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What is the main use of substances obtained from crude oil?
Plastics.
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Explain how crude oil is separated into fractions/fractional distillation.
Crude oil is heated to over 400°C so turns to gas/vapour, the gas then enters the fractional distillation column and rises to the top to cool. It then mostly condenses into a liquid but a different points, and the liquids are piped off as fractions.
Why do some gases condense higher up the fractional distilation column than others?
Because they have lower boiling points so stay at the top where it is cooler.
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Describe how a polymer is made (polymerisation).
Lots of monomers which have double links turn their links to single link and attach to another monomer to form a long chain (polymer).
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Why has the formula for polypropene [C2H4]n got brackets around it?
It shows that the amount of monomers joined together to make polypropene is a pattern repeated n times.
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Describe what the boiling point of a hard and strong polymer would be compared to a soft and waxy polymer.
The hardnpolymer would have a high boiling point because the molecules are close together/have stronger forces so are harder to weaken, whereas the soft polymer would have a low boiling point as its molecules are far apart, less dense + weak forces
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How do branches affect the properties of polymers?
They keep the molecules apart so the forces between them are weak, therefore making the properties include a low density, low boiling point etc.
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What is a crystaline polymer structure?
A polymer where there are regular patterns of molecules lined up straightly and close together.
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What are plasticisers and cross links and what do they do to polymers?
Plasticisers are small molecules that fit between polymer molcules, keeping them apart and weakening the forces so polymer is softer + more flexible. Cross links join molecules so they become rigid + strong.
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What is nanotechnology?
Technology using nanoparticles which are very small particles/ use and control of structures that are very small.
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What are nanoparticles?
Tiny pieces of a material. e.g. gold, made of no more than a thousand atoms.
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Give an example of a nanoparticle and what it is used for.
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