Using Materials

Question 1

Define corrosion

Answer 1

The destruction of material by chemical reactions with substances found in the material
When chemicals in the water dissolve in the rocks, causing then to break up (solution)

Question 2

How can corrosion affect a metal?

Answer 2

• appearance

- strength

Question 3

Define rusting

Answer 3

A corrosion process in which iron or steel reacts with oxygen and water

Question 4

What is the equation for rusting?

Answer 4

Iron + oxygen + water ——> hydrated iron oxide

Question 5

How can hydrated iron oxide be seen on rusty objects?

Answer 5

The orange-brown substance seen on the surface of rusty objects

Question 6

Rustyjbg experiment explained

Question 7

State what will happen to each of these test tubes (rusting)
Air and water
Water but no air
Air but no water

Answer 7

Air and water = rusting occurs
Water but no air = NO rusting
Air but no water = NO rusting
Rusting only can occur in the presence of both air and water

Question 8

How can rust be prevented?

What do these provide?

Answer 8

Coating iron and steel with: 
- paint 
- oil or grease 
- plastic 
- a less reactive metal
- a more reactive metal
These provide a barrier between iron and air / water