4.3.3 Using Electrolyisis To Extract Metals Flashcards
1
Q
Why do you use electrolysis to extract some metals?
A
- If the metal is too reactive to be extracted by reduction
- If the metal reacts with carbon
2
Q
Bauxite
A
Aluminium ore
3
Q
Aluminium ore
A
Bauxite
4
Q
Compound by which aluminium is extracted?
A
Aluminium oxide
5
Q
What must be done to aluminium oxide before it can undergo electrolysis?
A
Must be melted
6
Q
Why is extracting aluminium expensive?
A
- Takes a lot of energy
- This is expensive
7
Q
Why is cryolite added to aluminium oxide?
A
To lower the melting point
8
Q
What is the electrolyte aluminium is extracted from?
A
Aluminium oxide in cryolite
9
Q
Why must the positive electrode (anode) constantly be replaced?
A
It burns away as the carbon anode reacts with oxygen to produce CO2
10
Q
Why can’t aluminium be extracted using carbon?
A
It is more reactive than carbon
11
Q
Bauxite symbol
A
Al2 O3
12
Q
Why is a mixture used as the electrolyte for extracting aluminium? (2p)
A
- Cryolite is added to reduce the melting point
- So less energy needed to melt it
