C2.2.4-6 How structure influences the properties and uses of substances

Question 1

What does conduction depend on?

Answer 1

The ability of delocalised electrons to move throughout the metal

Question 2

Why can some metals be bent and shaped?

Answer 2

The layers of atoms in metals are able to slide over each other

Question 3

What are alloys made from and why are they harder than pure metals?

Answer 3

• Two or more different metals

- Different sized atoms distort the layers (no sliding)

Question 4

Give an example of a shape memory alloy? What is an advantage of using them?

Answer 4

• Nitinol: nickel and titanium, dental braces, glasses

- They can return to their original shape after being deformed

Question 5

What two things do the properties of polymers depend on?

Answer 5

• What they are made from

- The conditions under which they are made

Question 6

What is different about the production of LDPs and HDPs?

Answer 6

They’re produced using different catalysts and reaction conditions

Question 7

Identify what the following polymers consist of:

a) Thermosoftening polymers
b) Thermosetting polymers

Answer 7

a) IINDIVIDUAL, TANGLED poloymer chains

b) Polymer chains with CROSS-LINKS between them

Question 8

Why do thermosetting polymers not melt when heated?

Answer 8

Due the strong intermolecular forces in the cross-links

Question 9

What size are nanoparticles in: nanometres and m

Answer 9

1-100nm

1.0 x 10^-9 m

Question 10

Do nanoparticles have a low or high surface area to volume ratio?

Answer 10

High

Question 11

What uses could nanoparticles be developed for? (up to 5)

Answer 11

• COSMETICS, sun tan creams/ deoderants
• New COMPUTERS
• Highly selective SENSORS
• Stronger and lighter CONSTRUCTION MATERIALS
• New CATALYSTS