J Brewin Deer Park School Electrolysis 25 June 2013 J Brewin Deer Park School

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. J Brewin Deer Park School

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 Relights a glowing splint Anode Splitting a substance using electricity Cathode Electrolysis Negative electrode J Brewin Deer Park School

Electrolysis is splitting up substances using electricity (Lysis is latin for splitting) J Brewin Deer Park School

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 J Brewin Deer Park School

Positive Anode Negative Is Cathode Don’t get stressed in the exam: Remember PANIC J Brewin Deer Park School

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 J Brewin Deer Park School

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- J Brewin Deer Park School

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- J Brewin Deer Park School

The positively charged zinc ions are attracted to the negative electrode + - Zn+ Zn+ Cl- Cl- Cl- Cl- Zn+ Zn+ Cl- Zn+ J Brewin Deer Park School

The negatively charged chloride ions are attracted to the positive electrode + - Zn+ Zn+ Zn+ Zn+ Cl- Zn+ Cl- Cl- Cl- Cl- J Brewin Deer Park School

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. J Brewin Deer Park School

Compound Anode Cathode Sodium Bromide Potassium Iodide Calcium Fluoride Magnesium Oxide Lithium Chloride J Brewin Deer Park School

= bromide ion = lead ion Anode Cathode J Brewin Deer Park School

O.I.L.R.I.G. Oxidation is loss of electrons Reduction is gain of electrons J Brewin Deer Park School

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 J Brewin Deer Park School

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 J Brewin Deer Park School

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. J Brewin Deer Park School