Course Introduction This course covers Topic 5.4: Chemical Changes apart from 5.4.2 Reactions of Acids, which is covered in Reactions of Acids: GCSE AQA Chem for Comb Science.   This course is examined on Chemistry Paper 1 of the GCSE AQA Chemistry for Combined Science Course. Topics covered include: 5.4.1 Reactivity of metals 5.4.3 Electrolysis This course contains one required practical: Required practical activity 9: Investigate what happens when aqueous solutions are electrolysed using inert electrodes. The following information, included in this course, is assessed at Higher Tier only: Representation of reactions at electrodes as half equations