C6

Question 1

What does electrolysis mean?

Answer 1

Splitting up with electricity

Question 2

What happens during electrolysis?

Answer 2

1) A current is passed through an electrolyte and the ions move towards the electrodes where they react and the compound decomposes.

Question 3

What do the positive ions move towards and what do they do?

Answer 3

Cathode(- electrode) and gain electrons

Question 4

What do they negative ions move towards and what do they do?

Answer 4

Anode (+ electrode) and lose electrons

Question 5

What is the differnece between an electrolyte and electrode?

Answer 5

• Electrolyte is a liquid or solution that conducts electricity
• An electrode is a solid that conducts electricity

Question 6

After they have oxidised or reduced what happens?

Answer 6

There is a flow of charge through the electrolyte and the ions travel to the electrodes

Question 7

What happens when an ion gains or loses an electron?

Answer 7

They form an uncharged element and are discharged from the electrolyte

Question 8

What forms elements?

Answer 8

Electrolysis of molten ionic solids

Question 9

Why can’t an ionic solid be electrolysed?

Answer 9

The ions are in fixed positions and can’t move

Question 10

Why can molten ionic compounds be electrolysed?

Answer 10

The ions can move more freely and conduct electricity

Question 11

What happens at the cathode?

Answer 11

Positive metal ions are reduced

Question 12

What happens at the anode?

Answer 12

Non metal ions are oxidised

Question 13

How can metals be extracted from their ores?

Answer 13

By using electrolysis

Question 14

What happens if an element is more reactive than carbon?

Answer 14

You have to use electrolysis to extract the metal

Question 15

Why extracting metals expensive?

Answer 15

You need a lot of energy

Question 16

What is used to lower the melting point?

Answer 16

Cryolite

Question 17

Why does the positive electrode need to be continually replaced?

Answer 17

Oxygen is formed which reacts with carbon and will make carbon dioxide

Question 18

What ions are in the water?

Answer 18

H+ and OH-

Question 19

What happens if H+ ions and metal ions are present?

Answer 19

Hydrogen gas will be produced if the metal ions are more reactive than hydrogen

Question 20

What happens if the metal ion is less reactive than hydrogen?

Answer 20

A solid layer of the pure metal will be produced

Question 21

At the anode what happens if OH- and halide ions are formed?

Answer 21

The halide ions will be formed

Question 22

What are the halide ions?

Answer 22

Cl-,Br-,I-

Question 23

What happens if no halide ions are formed?

Answer 23

OH- ions are discharged and oxygen will be formed

Question 24

What is the oxygen equation?

Answer 24

4OH- —> O2 + 2H2O + 4e-

Question 25

What is the test for chlorine?

Answer 25

Bleaches Damp litmus paper = white

Question 26

Whats the test for hydrogen?

Answer 26

Squeaky pop with lighted splint

Question 27

Test for oxygen?

Answer 27

Relight glowing splint

Question 28

What’s the equipment for electrolysis?

Answer 28

Test tubes.
Electrolyte solutions.
100 cm3 beaker.
Stand and clamp.
Two carbon rod electrodes.
Two crocodile / 4 mm plug leads.
Low voltage power supply.
Blue litmus paper

Question 29

What’s the method for electrolysis?

Answer 29

1) Set up the apparatus
2) Add the aqueous solution to the beaker
3) Add to graphite rods and connect them to the power supply with the crocodile teeth
4) turn on power supply
5) Record results in a table and repeat for another solution and see if any metal has been formed
6)

Question 30

What ore is aluminium extracted from?

Answer 30

Bauxite