Extraction and Uses of Metals

Question 1

What is roasting?

Answer 1

A process in which a metal ore is heated in air to convert it into a metal oxide

Question 2

What economic factors are taken into consideration while extracting metals from their ores?

Answer 2

• Cost of energy

- Cost of reducing agent

Question 3

The benefit of adding molten cryolite to aluminum oxide:

Answer 3

• Reduces the melting point to 1000⁰C

- Increases the electrical conductivity of the electrolyte

Question 4

What is an alloy? Give examples

Answer 4

An alloy is a mixture of metal with other elements or carbon

Example: brass, bronze, cupronickel, and steel

Question 5

Why are alloys harder than pure metals

Answer 5

because they contain atoms of different sizes which distorts the regular arrangement of lattice.
This makes it more difficult for the layers to slide over each other, making it harder and stronger than pure metal

Question 6

Why is aluminum resistant to corrosion?

Answer 6

Because it has a very thin but very strong layer of aluminium oxide which prevents anything else reaching and reacting with the surface

Question 7

What are the disadvantages of mild steel?

Answer 7

• Rusts

- Denser than aluminum

Question 8

Properties of high-carbon steel:

Answer 8

Harder, not as malleable and ductile but more brittle

Question 9

What is stainless steel?

Answer 9

An alloy of iron with chromium and nickel

Question 10

Uses of stainless steel:

Answer 10

• Kitchen sinks, knives, saucepans, gardening tools, and as vessels in the brewing, dairy, and chemical industries