extracting aluminium Flashcards
1
Q
when an aluminium ore is treated what is produced?
A
aluminium oxide
2
Q
what is powdered aluminium oxide dissolved in to lower melting point?
A
molten cryolite
3
Q
why does aluminium oxide’s melting point have to be lowered?
A
so less energy is required to break it’s strong ionic bonds and so it’s cheaper
4
Q
what happens at the cathode?
A
aluminium ions gain electrons and form aluminium atoms
5
Q
what happens at the anode?
A
at the anode, oxide ions lose electrons and form oxygen gas
6
Q
why do the anodes have to be replaced frequently?
A
The oxygen reacts with the carbon anodes, forming carbon dioxide. So the anodes are gradually oxidised. They must be replaced frequently.
