Polymers

Question 1

Monomer

Answer 1

Small molecular unit that can bond together to form a big long chain (polymer) e.g. alkenes

Question 2

Polymer

Answer 2

commonly known as plastics

Formed by a chemical reaction (addition or condensation polymerisation)

from monomer units that join together to form a big long chain

Question 3

How can we affect Polymer properties

Answer 3

Properties depend on two factors:

• Conditions they are made in
• The monomer that has been used.

Example: High density and low density poly(ethene) are made using different catalysts and conditions.

Question 4

Explain why Thermosetting polymers have higher melting points and are stronger.

Answer 4

Polymer chains with cross-links between them

strong intermolecular forces between the chains

require lots of energy to break.

Question 5

Explain why Thermosoftening polymers have lower melting points and are softer.

Answer 5

Consists of individual, tangled polymer chains

with no cross links between chains.

weak intermolecular forces between the chain

require little of energy to break.

Question 6

Repeat unit

Answer 6

Summary of the repeating section in a polymer chain

n CH2=CH2 → -(-CH2-CH2)n