Chapter 20 - Polymers

Question 1

What is a polymer?

Answer 1

A very large organic molecule built up from many small units known as monomers

Question 2

What is polymerisation?

Answer 2

Process of joining together a large number of monomers to form a polymer. The monomers are joined by covalent bonds

Question 3

Does polyethene have a large or small molecular mass?

Answer 3

Very large - thousands of C atoms in each polyethene molecule

Question 4

What is addition polymerisation?

Answer 4

Occurs when unsaturated monomers join together without losing any molecules or atoms to form addition polymers

Question 5

Why is it possible for alkenes to undergo addition polymerisation?

Answer 5

The monomer used for addition polymerisation is usually unsaturated (contains a C-C double/triple bond). Hence at high temperature and pressure, thousands of alkene molecules join together to form polymers

Question 6

What is the simplest addition polymer?

Answer 6

Poly(ethene) aka polyethylene. Produced by the addition polymerisation of ethene monomers

Question 7

Describe how poly(ethene) is formed

Answer 7

1) At high temperature and pressure and in the presence of a catalyst, the C-C double bonds of the ethene molecules(monomers) break
2) Each monomer forms single bonds with two other monomers. Polymer poly(ethene) is formed

Question 8

A polymer is usually made up of similar units joined together known as ____ ____

Answer 8

Repeating units

Question 9

What is the repeating unit of poly(ethene)?

Answer 9

H H
I I
H - C - C - H
I I
H H

Question 10

The formula of a polymer can be written using its repeat unit. Hence the formula of poly(ethene) is:

Answer 10

H H
I I
[ - C - C - ] n
I I
H H
OR ( - CH2 - CH2 - )n

Where n represents a large number