1. Electrolysis

2. Learning Objectives By the end of the lesson I will be able to:
1) Understand the process of electrolysis.
2) Explain how we can use electrolysis to extract aluminium from its ore.

3. Match up the words with their descriptions
The substance being broken down
Test for Oxygen
Positive electrode
Test for Hydrogen
Makes a ‘popping’ noise when lit
Electrolyte
Splitting a substance using electricity
Anode
Relights a glowing splint
Cathode
Negative electrode
Anion
Positive ion
Cation
Negative ion
Electrolysis

4. Electrolysis is splitting up substances using electricity
(Lysis is latin for splitting)

5. What is electrolysis?
Electric current is used to breakdown a substance made up of ions
An electrolyte is the name for the substance being broken down

6. Video
Complete the fill in the gap sheet while you watch the video.

7. Positive Anode Negative Is Cathode Don’t get stressed in the exam:
Remember PANIC

8. Electrolysis Apparatus
Anode
(+ve electrode)
Electrolyte
Cathode
(-ve electrode)
power supply
Complete questions 1 & 2

9. Electrolysis Apparatus
Electrolyte: this is what will be electrolysed
Anode
(+ve electrode)
Cathode
(-ve electrode)
power supply

10. Aluminuim oxide electrolysis
Molten aluminium oxide is created by dissolving the aluminium in molten cryolite.
This forms the electrolyte, through which electricity can pass.
An electric current is passed through the electrolyte.
This causes the aluminium oxide to split into aluminium and oxygen.
Aluminium ions are positively charged (cations) and go to the..
Cathode
Oxygen ions are negative (anions) and go to the...
Anode

11. Electrolysis of Molten NaCl- +
ANODE
CATHODE
The metal goes to the cathode and the non metal goes to the anode. - +
Na+
Cl-
Cl-
Cl-
Na+
Na+
Na+
Cl-

12. molten zinc chloride (ions free to move)+ -
negative electrode
positive electrode
(anode)
(cathode)
Zn+
Cl-
Zn+
Zn+
Zn+
Cl-
Cl-
Cl-
Cl-
Cl-
Zn+
Zn+
Zn+
molten zinc chloride (ions free to move)
Cl-
Zn+
Cl-

13. The positively charged zinc ions are attracted to the negative electrode+ -
Zn+
Zn+
Cl-
Cl-
Cl-
Cl-
Zn+
Zn+
Cl-
Zn+

14. The negatively charged chloride ions are attracted to the positive electrode+ -
Zn+
Zn+
Zn+
Zn+
Cl-
Zn+
Cl-
Cl-
Cl-
Cl-

15. True or False
Electrolysis is the splitting of a substance using electricity.
The anode is negative.
Anions are negative
Aluminium oxide is found in bauxite.
Cathode is negative.
Cations are negative.

16. Compound
Anode
Cathode
Sodium Bromide
Potassium Iodide
Calcium Fluoride
Magnesium Oxide
Lithium Chloride

17. = bromide ion
= lead ion
Anode
Cathode

18. O.I.L.R.I.G. Oxidation is loss of electrons
Reduction is gain of electrons

19. A grade work = bromide ion At the cathode:
= lead ion
At the cathode:
Pb+ gains electrons to form lead metal.
It is REDUCED.
At the anode:
Br- loses electrons to form bromine gas.
It is OXIDISED.
Anode
Cathode
A grade work

20. Summary Cathode Negative Anode Positive Positive ions attracted
Negative ions attracted
REDUCTION happens here ( positive ions gain electrons)
OXIDATION happens here (negative ions lose electrons
Summary

21. Stand up sit down One person names a topic.
All pupils write a key word to do with the topic on a whiteboard
The person who chose the topic has 30 seconds to name as many key words to do with the topic as they can.
If the word the pupil has written down is said they have to sit down.
The aim for the topic chooser is to get everyone to sit down.
The aim for the pupils writing down a word is to out fox the topic chooser with a relevant but obscure word.