C4 - Extraction Of Metals

Where is gold found in the Earth?

As pure metal (native), because it is very unreactive.

Why can gold be found as nuggets in the Earth?

Because gold does not easily react with other elements.

How are most metals found in the Earth?

As compounds, such as oxides (e.g. iron oxide, copper oxide).

What does a more reactive element do to a less reactive element in a compound?

It displaces the less reactive element.

Give an example of a metal displacement reaction.

Magnesium + Iron oxide → Magnesium oxide + Iron.

In terms of oxygen, what is oxidation?

Gain of oxygen.

In terms of oxygen, what is reduction?

Loss of oxygen.

In the reaction Magnesium + Iron oxide → Magnesium oxide + Iron, which element is reduced?

Iron (it loses oxygen).

In the reaction Magnesium + Iron oxide → Magnesium oxide + Iron, which element is oxidized?

Magnesium (it gains oxygen).

Why is carbon used to extract metals?

Because carbon is cheap and reactive enough to displace less reactive metals.

What is the general reaction when carbon reduces a metal oxide?

Carbon + Metal oxide → Carbon dioxide + Metal.

Which metals can be extracted using carbon?

Metals less reactive than carbon (e.g. zinc, iron, copper).

Why can't zinc extract calcium from calcium compounds?

Because zinc is less reactive than calcium.

Where is iron extracted industrially?

In a blast furnace.