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7. Diagram 1 shows a reversible chemical reaction.

What are process X and Y?X Y

A. Polymerisation DepolymerisationB. Depolymerisation PolymerisationC. Depolymerisation HydrolysisD. Polymerisation Condensation

8. Natural rubber is soft, elastic and not heat resistant. How can it be made harder, moreelastic and more heat resistant?

A. Heat it with carbonB. Add vinegar with it

C. Immerse it in ammonia solutionD. Heat it with sulphur

9. Why is polystyrene suitable as food containers

A. It is thermoset plasticB. It can be moulded and recycled repeatedlyC. It is heat resistantD. It is non-flammable

10. Which is a natural polymer?A. PerspexB. ProteinC. PVCD. Neoprene

Molecules of aminoacids

X

YProtein

Diagram 1

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PAPER 2SECTION A + B

1. The figure below shows the making up of synthetic monomers into polymers

a) Give the definition of [2 marks]i) polymer

________________________________________________________________

ii) monomer

________________________________________________________________

b) Identify process X [1 mark]

______________________________________________________________________

c) Name two plastics which have linear polymers as shown in the diagram. State oneuse for each of the plastics named. [4 marks]

Plastic A:_______________________________________________________________

Plastic B :______________________________________________________________

d) Name both monomer and polymer for natural rubber? [2 marks]i) Monomer:

_______________________________________________________

Synthetic monomers

X

Polymers

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ii) Polymer:

_______________________________________________________

2. a) Differentiate between thermoplastics and thermosetting plastics in terms of theircapacity to be moulded. [ 2 marks]

Thermoplastic Thermosetting plastic

b) What is the reason for this difference in property between these two classes ofplastics? [2 marks]

______________________________________________________________________

c) Give one example of the thermoplastic and one for thermosetting plastics. [2 marks]

Thermoplastic Thermosetting plastic

d) State two ways in which plastics may cause pollution to the environment. [ 2 marks]i)

________________________________________________________________

________________________________________________________________

ii)_______________________________________________________________

_______________________________________________________________

SECTION C

1. (a) List down four products made up by synthetic rubber. [4 marks](b) Name a process to improve the quality of natural rubber. Lists 2 of its

Improvement. [3 marks].(c) Lists down 3 characteristics of a synthetic rubber. [3 marks]

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MODULE 14 - ANSWERS

PAPER 11. B2. C3. D

4. B5. C6. A7. A8. D9. B10. B

PAPER 2SECTION A + B

1. (a) (i) a combination of monomers which bound together

(ii) a small unit of molecule(b) Polymerisation(c) Plastic A: Thermoplastics : plastic mineral bottles, plastic bag, plastic wrapping

Plastic B: Thermosetting plastics: melamine plates, mugs and protective coveringsof electrical appliances

(d) i) isopreneii) polyisoprene

2. a.Thermoplastic Thermosetting plastic

Can be remoulded more than

once/repeatedly

Only can be remoulded once

b. Thermoplastics do not cross links between the polymers, so that it can easily slideThermosetting plastics have cross links between polymers, so it will restrict their

ability to slide over one anotherc.

Thermoplastic Thermosetting plastic

Polythene/ Perspex Bakelite/ Epoxy glue

d. It produces toxin gases when burnt They can choke drains and other drainage system

Most of them are non-biodegradable, thus it can pollute soil and water

Section C1 (a) Gloves, raincoat, hoses, gaskets and fan belt.

(b) Vulcanisation. Much harder, more resistant or more durable to chemical changes.(c) Elastic, heat resistant, water resistant, chemical resistant, oil resistant, strong