Active learning ideas
Electrolysis is the process of using electricity to split ionic compounds into their constituent elements. Students learn about the movement of ions to the anode and cathode and how to predict the products of electrolysis for both molten and aqueous solutions. This topic includes the industrial extraction of aluminium and the electrolysis of brine.
Activity 01
Mark out an 'anode' and 'cathode' on the floor. Students act as positive and negative ions, moving toward the correct electrode when the 'power' is turned on and explaining what happens to their charge.
What is the process of electrolysis?
Activity 02
Groups perform the electrolysis of copper chloride and sodium chloride solutions. They use indicator paper and observations at the electrodes to identify the gases produced and test their predictions.
Why must the electrolyte be molten or dissolved in water?
Activity 03
Give pairs a list of aqueous solutions. They must use the 'reactivity of hydrogen' rule to predict which element will form at the cathode and share their reasoning with another pair.
How do we predict the products at the anode and cathode?
Templates
Drop them into your lesson, edit them, and print or share.
A few notes on teaching this unit
Watch Out for These Misconceptions
Students often think that electrons flow through the electrolyte solution.
Clarify that current in the solution is carried by moving ions, not electrons. Electrons only flow through the external wires. Using a diagram-labelling activity helps students distinguish between the two types of charge carriers.
There is a belief that the metal always forms at the cathode in aqueous solutions.
Explain that if the metal is more reactive than hydrogen, hydrogen gas will form instead. Using a 'decision tree' poster during practical work helps students apply this rule consistently.
Methods used in this brief
Quantitative Chemistry
An introduction to the conservation of mass, relative formula mass, and the mole concept. Students will perform calculations to determine the amounts of substances in chemical reactions.
8 methodologies
Chemical Changes and Reactivity
Students investigate the reactivity series of metals and their reactions with acids and water. The topic includes the extraction of metals and redox reactions.
8 methodologies