Endothermic Reaction

We demonstrate an endothermic reaction by mixing hydrated barium hydroxide with ammonium thiocyanate. When these two solids react they take heat from the surrounding air. Chemistry - Reactions - Learning Points. Breaking bonds takes in energy. Forming bonds releases energy. Exothermic reactions release more energy than they take in. Endothermic reactions take in more energy than they release. A Twig Experiment Film. Let students experience real experiments in lab conditions anywhere, from setup, method all the way through to analysis and real-world application.