Polymers - Topic 9

Question 1

Polymer:

Answer 1

a substance of high average relative molecular mass made up of small repeating units (monomers)

Question 2

Polymerisation:

Answer 2

• the joining up of many small molecules (called monomers) to form extremely long chains (called polymers)
• the repeat unit has the same atoms as the monomer because no other molecule is formed in the reaction

Question 3

General equation for polymerisation:

Answer 3

n M → —————M-M-M-M-M-M——————-

Question 4

What is the addition polymer formed called?

Answer 4

polythene

Question 5

Change in structure from alkene to poly(alkene):

Answer 5

all atoms coming off carbon must be vertical to C

Question 6

How can other addition polymers be made?

Answer 6

by combing together other monomer molecules containing C=C to include ply(propene), poly(chloroethene), (PVC) and poly(tetrafluoroethene)

Question 7

Properties of poly(ethene):

Answer 7

• flexible
• cheap
• electrical insulator
• inert/unreactive
• waterproof/weatherproof
• light

Question 8

Uses of poly(ethene):

Answer 8

• plastic bags and bottles
• coating on electrical wires

Question 9

Properties of poly(propene):

Answer 9

• flexible
• strong

Question 10

Uses of poly(propene):

Answer 10

• buckets
• crates

Question 11

Properties of poly(chloroethene)/PVC:

Answer 11

• tough
• cheap
• long lasting/durable
• good insulator
• waterproof/weatherproof
• inert/unreactive

Question 12

Uses of poly(chloroethene)/PVC:

Answer 12

• window frames
• gutters
• water pipes
• insulation for electrical wires

Question 13

Properties of PTFE:

Answer 13

• slippery
• non stick
• tough
• high mp/high resistance
• inert/unreactive

Question 14

Uses of PTFE:

Answer 14

non-stick coating on pans

Question 15

Problems with polymers:

Answer 15

• availability of starting materials
• persistence in landfill sites, due to non-biodegradability
  
  • don’t break down in the environment via natural processes
  • end up with a build-up of non-disposable plastics
  • fill up/new landfill sites needed
  • harmful to animal habitats
• toxic gases produced during disposal by combustion/burning
  
  • HCl acid/gas produced from burning of PVC
  • CO2 released contributing to global warming
  • CO released
  • toxic ash/solids formed
• requirement to sort polymers so that they can be melted and reformed into a new product

Question 16

Advantages of recycling polymers:

Answer 16

• don’t need to make as many new polymers - saves crude oil, conserving finite resources
• reusing waste materials is better for the environment than burning them (as won’t release toxic emissions) or putting them in landfills (as they are non-biodegradable)
• more economically viable instead of making more polymers

Question 17

Disadvantages of recycling polymers:

Answer 17

• difficult and expensive to first separate the different polymers - need to be sorted into types which is time-consuming
• transport to collection area/recycling point uses fuel
• slow process
• degrading - each time you recycle a plastic you degrade some of its qualities
• collection point may cause litter/eyesore

Question 18

What is DNA and what is it made from/of?

Answer 18

DNA is a polymer made from 4 different monomers called nucleotides

Question 19

What is starch and is it made up of?

Answer 19

starch is a polymer based on sugars

Question 20

What are proteins and what are they made up of?

Answer 20

proteins are polymers based on amino acids

Question 21

Why are polyesters condensation polymers?

Answer 21

• In condensation polymerisation, a small molecule is formed as a by-product each time a bond is formed between two monomers
• Alcohol and carboxylic acid functional groups react, losing a small molecule – water
• This is an ester – therefore a polyester is a lot of these monomers (esters)

Question 22

Condensation polymers:

Answer 22

• polymers formed from condensation reactions between monomers
• a small molecules (often water) is produced as well as the polymer

Question 23

What must each monomer unit have to make condensation polymers?

Answer 23

• each monomer unit must have 2 functional groups that can react with the other monomer
• in the process of reaction a 2nd molecule e.g. water, is eliminated

Question 24

2 main types of condensation polymers:

Answer 24

• polyesters
• polyamides

Question 25

How are esters formed?

Answer 25

- esters formed on reaction between carboxylic acids and alcohols with the loss of a water molecule - esterification - in a condensation reaction the 2 molecules join a produced a larger molecule whilst eliminating a small molecule - during esterification this small molecule is water

Question 26

Properties of esters:

Answer 26

- characteristic smells - often used in perfumes - insoluble in water

Question 27

Ester link:

Answer 27

the functional group -COO

Question 28

How is a polyester formed when a monomer molecule containing 2 carboxylic acid groups is reacted with a monomer molecule containing 2 alcohol groups?

Answer 28

- the dicarboxylic acid loses the OH group off of each COOH group - the di-alcohol loses the H off of each OH group - the remaining molecules join together to make a polyester (the alcohol group combines with a carboxylic acid group) and an ester link is formed - a water molecule is eliminated - so basically if a dicarboxylic acid reacts with a diol, a polymer called a polyester is formed and water is released

Question 29

How is a molecule of water formed each time an ester link is formed?

Answer 29

the OH and H groups combine to make H2O

Question 30

What type of polymer is DNA?

Answer 30

condensation polymer

Question 31

Peptide bond formation:

Answer 31

Question 32

Protein/polypeptide:

Answer 32

Question 33

How is polymer formed from an alkene?

Answer 33

- double carbon bond is broken - many monomers link together to form a long chain

Question 34

Do polymers of alkenes decolorise bromine water?

Answer 34

no - polymers do not decolorise bromine water