Exothermic and endothermic changes
Exothermic and endothermic changes
During a chemical reaction, bonds in the reactants are broken and new bonds form in the products. That means energy is transferred between the reacting chemicals and the surroundings, usually as heat.
Step-by-step lessons covering Edexcel GCSE Chemistry Heat energy changes in chemical reactions for Foundation and Higher tier. Each lesson works through exam-style questions in Paper 1 and Paper 2 format. Nail the core quantitative topics — moles, balancing equations and calculations — early on, since they underpin higher-tier questions across every paper and topic.