iGCSE Scheme of Work Year 10 July 2011 Electrolysis Lesson Learning Activities Assessment Safety Other Objectives emphasis STARTER This practical produces chlorine Ask students to work in pairs to predict the Predict describe – gas (CLEAPSS Lesson 4 products of electrolysis of molten sodium chloride experiments to Hazcard 22 – and a solution of sodium chloride. Students should investigate could irritate also complete half equations to show the formation of electrolysis, asthmatics) and Electrolysis the products. (10 minutes) should only be using inert of solutions completed in a electrodes, of well-ventilated aqueous area, and once solutions such MAIN the products have as sodium Students can complete their own electrolysis of been tested the sodium chloride and test for products. They should equipment should chloride, be switched off. copper(II)sulfate record their observations in a diagram of the The solution and dilute apparatus Drawn before they start the practical). produces sodium sulfuric acid and Pupils should also add the half-equations for each hydroxide and this predict the electrode. (20 mins) is why gloves should be worn to products collect the gas by Discuss what is left in solution after the electrolysis and displacement. write ionic why? representing the reactions at the PLENARY electrodes during Spot the errors Show the pupils the ‘electrolysis errors’ electrolysis diagram and get pupils to correct the diagram in the back of their books.
iGCSE Scheme of Work Year 10 July 2011 Electrolysis Lesson Learning Objectives Activities Assessment Safety Other emphasis Lesson 4 Electrolysis of solutions describe experiments to investigate electrolysis, using inert electrodes, of aqueous solutions such as sodium chloride, copper(II)sulfate and dilute sulfuric acid and predict the products write ionic representing the reactions at the electrodes during electrolysis STARTER Predict – Ask students to work in pairs to predict the products of electrolysis of molten sodium chloride and a solution of sodium chloride. Students should also complete half equations to show the formation of the products. (10 minutes) MAIN Students can complete their own electrolysis of sodium chloride and test for products. They should record their observations in a diagram of the apparatus Drawn before they start the practical). Pupils should also add the half-equations for each electrode. (20 mins) Discuss what is left in solution after the electrolysis and why? PLENARY Spot the errors Show the pupils the ‘electrolysis errors’ diagram and get pupils to correct the diagram in the back of their books. This practical produces chlorine gas (CLEAPSS Hazcard 22 – could irritate asthmatics) and should only be completed in a well-ventilated area, and once the products have been tested the equipment should be switched off. The solution produces sodium hydroxide and this is why gloves should be worn to collect the gas by displacement.