chemistry - separate chemistry 2: polymers (9.17 - 9.25)

9.17 polymer - mass, made of

substance of high average relative molecular mass

made up of small repeating units

9.18 ethene molecules combining - type of reaction, product

ethene molecules (monomers) combine together in polymerisation reaction (addition polymerisation)

addition polymer formed called poly(ethene)

9.19 how is addition polymer poly(propene) made?

propene monomer molecules combine together

9.19 how is addition polymer poly(chloroethene) (PVC) made?

chloroethene monomer molecules combine together

9.19 how is addition polymer poly(tetrafluoroethene) (PTFE) made?

tetrafluoroethene monomer molecules combine together

9.20 deduce structure of monomer from structure of addition polymer

remove brackets & extension bond lines

draw double bond between carbon atoms

9.20 deduce structure of addition polymer from structure of monomer

add brackets & extension bond lines

draw single bond between carbon atoms

9.21 uses of poly(ethene)

flexible, cheap, good insulator

plastic bags, bottles, cling film, polytunnels

9.21 uses & properties of poly(propene)

flexible, doesn’t shatter

buckets, bowls, crates, ropes, carpets

9.21 uses & properties of poly(chloroethene) (PVC)

tough, good insulator, can be made hard/flexible

window frames, gutters, pipes, insulation for electrical wires

9.21 uses & properties of poly(tetrafluoroethene) (PTFE)

tough, slippery

non-stick coating for frying pans & kitchen utensils, burette taps, stain-proofing clothing & carpets

9.22 why are polyesters condensation polymers?

polyesters made by condensation polymerisation

monomers join together & eliminate small molecule (e.g. water)

9.22 how is polyester formed?

monomer containing 2 carboxylic acid groups reacts with monomer containing 2 alcohol groups

in presence of catalyst

water produced

9.22 how is molecule of water formed each time ester link formed?

atoms in red oval join together to form water

leave other atoms available to bond to form ester link

9.23 problems with polymers - availability of starting materials

monomers needed to make synthetic polymers obtained from crude oil (finite, non-renewable resource)

9.23 problems with polymers - persistence in landfill sites

stay in landfill sites - non-biodegradable

9.23 problems with polymers - gases produced during disposal

disposed by combustion - produces CO₂ (greenhouse gas) & toxic substances

9.23 problems with polymers - requirement to sort polymers

need to sort polymers - melted & reformed into new product

9.24 advantages of recycling polymers

monomers needed to make synthetic polymers obtained from crude oil (finite, non-renewable resource) → recycling conserves crude oil supplies

disposed by combustion - produces CO₂ (greenhouse gas) & toxic substances → recycling reduces greenhouse gas emission by combustion

9.24 disadvantages of recycling polymers

many steps needed to obtain new item - difficult & expensive (to sort polymers)

9.25 DNA - what is it & what is it made from?

polymer

made from 4 diff. monomers called nucleotides

9.25 starch - what is it & what is it based on?

polymer

based on sugars

9.25 proteins - what are they & what are they based on?

polymers

based on amino acids