Chemistry / Science GCSE: Investigate electrolysis of aqueous solutions using inert electrodes

A demonstration of the key points of the required practical to investigate electrolysis of aqueous solutions using inert electrodes for GCSE chemistry and combined science.

This short film shows that there are several ways to carry out electrolysis and highlights the common features of each method. It explores the science behind the practical method, including demystifying some of the key scientific terminology, and supports students to predict what will form at each electrode.

Teacher Notes

The practical allows development of Apparatus & Techniques Chemistry 3 and 7 (DfE GCSE subject content guidance, Appendix 4).

This short film could be used before or after the investigation is carried out. If used before, students should first study some of the theory behind electrolysis.

The film can then be used to rehearse some of the key elements and key terminology used in electrolysis.

If used after the investigation, it could be used to highlight a range of methods to investigate separation by electrolysis and to support predicting what will form at each electrode.

Points for discussion:
Even where the process of electrolysis is familiar to students and they can recall the method, the purpose of the apparatus and method steps are often more challenging.

This film shares the common features of electrolysis systems which will support students it apply their knowledge to unfamiliar methods and contexts. If it is not possible to demonstrate micro-scale electrolysis or the Hofmann voltameter directly with students, this film could be used to introduce them to these methods.

Questions linked to the science behind the practical are also often challenging and this film highlights how to predict what will form at each electrode.

Students should be encouraged to draw the apparatus for electrolysis and to practise identifying the key elements in a variety of electrolysis methods.

Suggested activities:
Students should practise explaining the purpose of the apparatus used in several different electrolysis systems so that they can apply key learning of the process.

Working scientifically criteria states that students should, ‘apply a knowledge of a range of techniques, instruments, apparatus and materials to select those appropriate to the experiment’ (DfE GCSE subject content guidance, Working scientifically).

Curriculum Notes

Suitable for teaching chemistry and combined science at Key Stage 4 and GCSE in England, Wales and Northern Ireland, and at National 4 and 5 in Scotland.

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