Topic 6 - electrolysis

Question 1

What does electrolysis do?

Answer 1

Breaks down a substance using electricity

Question 2

Ionic compounds can only be electrolysed when…?

Answer 2

They are molten or dissolved in water

Question 3

Why are ionic compounds electrolysed in water?

Answer 3

Their ions are then free to move and carry their charge to the electrodes

Question 4

In electrolysis, positive ions move to the…?

Answer 4

Cathode (negative electrode)

Question 5

In electrolysis, negative ions move to the…?

Answer 5

Anode (positive electrode)

Question 6

What happens at the positive electrode (anode)?

Answer 6

The negative ions lose their extra electrons and become oxidised

Question 7

Either hydrogen or the metal is produced at which electrode?

Answer 7

Cathode

Question 8

Oxygen gas is given off, discharge hydroxide ions produced from water happens at which electrode?

Answer 8

Anode

Question 9

From the ore bauxite, what is electrolysed?

Answer 9

Aluminium oxide

Question 10

Why is aluminium oxide mixed with molten cryolite?

Answer 10

To lower the melting point, reducing the energy needed to extract the aluminium