Oxidation (Form 1).

Question 1

Define rusting.

Answer 1

Corrosion of a material containing iron by the formation of iron oxide.

Question 2

State the word equation for rusting.

Answer 2

Iron + oxygen + water → iron oxide (rust).

Question 3

Rusting cannot be reversed. Name 3 ways of preventing rusting.

Answer 3

• Painting.
• Galvanising.
• Electroplating.

Question 4

What can you coat iron with to avoid oxygen coming in direct contact with the iron?

Answer 4

By coating iron with oil, grease, or paint, the oxygen cannot come into direct contact with the iron.

Question 5

What is the disadvantage of the painting to prevent rusting method?

Answer 5

The disadvantage of this method is that the protective coat must be renewed frequently.

Question 6

Describe galvanising.

Answer 6

Iron can also be protected against rusting by coating it with a thin layer of another metal that does not react with oxygen, for example, zinc.

Question 7

Describe electroplating.

Answer 7

In electroplating, an electric current is used to deposit a thin layer of non-corroding metal onto the surface of an iron or steel object.

Question 8

Fill in the missing answers:
Electroplating is done by a chemical process called ______. For _____ to happen three components are needed: a ______ source, ________, and _______.

Answer 8

Electroplating is done by a chemical process called electrolysis. For electrolysis to happen three components are needed: a power source, electrodes, and electrolyte.

Question 9

Define electrolysis.

Answer 9

Electrolysis is the breakdown of a compound into its elements when an electric current passes through a solution containing that compound.