C6 Electrolysis

Question 1

What is electrolysis

Answer 1

The breaking down of a substance using electricity.

Question 2

What is an electrolyte

Answer 2

-The compound that is broken down by electrolysis.
-They are ionic compounds that are in the molten state, or dissolved in water

Question 3

How does electrolysis work

Answer 3

Positive ions move to the cathode (negative electrode), while negative ions move to the anode (positive electrode). Metals form at the cathode whilst non-metals form at the anode

Question 4

What happens during the electrolysis of molten salts

Answer 4

A metal forms at the cathode and a non-metal forms at the anode

Question 5

What are the products of electrolysis of molten aluminium oxide c

Answer 5

Aluminium will form at the negative electrode and oxygen will form at the positive electrode

Question 6

What happens when ions reach an electrode

Answer 6

They gain or lose electrons. As a result, they form atoms or molecules of elements.
-positive ions gain electrons from the cathode
-negative ions lose electrons at the anode.

Question 7

What do lead and bromine form during electrolysis

Answer 7

Molten lead bromide

Question 8

What are cations

Answer 8

Positively charged ions
Cations are pussitive

Question 9

What are anions

Answer 9

Negatively charged ions

Question 10

How is aluminium extracted from its ore

Answer 10

1.Bauxite
(purified-aluminium oxide is separated from ore)
2.Aluminium oxide
(Extracted by electrolysis)
3.Aluminium

Question 11

How is aluminium made able to be electrolysed

Answer 11

The aluminium oxide is mixed with molten cryolite, the molten mixture can be electrolysed at about 850°C. This is done so that the mixture melts at a lower temperature than aluminium oxide which reduces the cost of heat energy

Question 12

What is aluminium oxides boiling point

Answer 12

2050°C

Question 13

In the electrolysis of aluminium oxide what forms at the cathode and anode

Answer 13

-Aluminium forms at the cathode (negative electrode)
-Oxygen forms at the anode (positive electrode)

Question 14

Why is aluminium expensive

Answer 14

High cost of electricity but also due to the cost of heat and replacement electrodes

Question 15

Why do the positive electrodes (anodes) have to be replaced at regular intervals

Answer 15

The graphite burns as it reacts at high temperature with the oxygen produced on its surface.