Addition Polymerisation

Question 1

What is a polymer

Answer 1

A polymer is a Marcomolecule linked together by many small repeating units known as monomers. This process is known as polymerisation

Question 2

Alkenes undergo addition polymerisation

Answer 2

It involves joining many unsaturated monomers(simple molecules), which contain C=C bonds together to form a polymer(marcomolecule) as the only product.

Conditions:
High temperature and pressure, catalyst

Question 3

Using ethernet as an example:

Answer 3

Ethene is monomer, and the resulting addition polymer is poly(ethene).

Question 4

Uses of polyethene:

Answer 4

High-density poly(ethene): HDPE: usee to make plastic toys and water pipes
Low-density poly(ethene): LDPE: used to make plastic bags and clingfilm

Question 5

Differences between Ethene vs poly(ethene)

Answer 5

Ethene Poly(Ethene)
———
Empirical formula: CH2. Empirical formula: CH2
Relative molecular mass: 28. Greater than 15000
Number of atoms per molecule: 6. At least 3000
Melting point: very Low. Munch higher than ethene(above rtp)
State at r.t.p: gas. Solid
Reaction with aqueous: rapid addition with bromine. - No reaction
Combustion in air: burns to form CO2 and H2O. - burns to form CO2 and H2O

Question 6

Uses of common polymers
Poly(chloroethene) or
PVC

Answer 6

For water pipes, waterproof plastic sheet, insulation for electric cables and wires

Question 7

Poly(phenylethene) or polystyrene

Answer 7

For packaging and containers for electrical goods, disposable cups and food containers used in fast food restaurants.

Question 8

Poly(tetrafluoroethene) or PTFE

Answer 8

Used to coat ‘non-stick’ pots and pans as it is chemically inert, heat resistant and repels water.

Question 9

Problem of plastics:

Answer 9

Plastics are non-biodegradable( cannot be broken down by bacteria in the soil)

Question 10

Advantages and disadvantages of plastics

Answer 10

Advantages- disadvantages
Common and cheap materials- plastics burns; a fire risk in buildings and vehicles
Corrosion resistant and durable- produce poisonous gases like carbon monoxide when burnt
Light and easily moulded into a variety of shapes- non biodegradable:pollutes the environment

Question 11

Plastics can be disposed by dumping or by incineration

State an advantage of disposing plastics by dumping over disposing by incineration

Answer 11

Reduces air pollution caused by the poisonous gases formed during incineration

Question 12

State two advantages of disposing of plastics by incineration, over disposing by dumping

Answer 12

1) Reduces land pollution caused by the landfill sites occupied by dumping
2) Heat produced from incineration can be used to generate electricity