Energetics
The resources in this list look at the energy changes associated with chemical reactions. The list includes experiments and other resources which can help students identify exothermic and endothermic reactions and explain why energy changes happen in terms of bond breaking and bond making.
Higher tier students are required to develop the above qualitative idea further and use bond energies to calculate the enthalpy change for a given reaction.
Whilst this list provides a source of information and ideas for experimental work, it is important to note that recommendations can date very quickly. Do NOT follow suggestions which conflict with current advice from CLEAPSS, SSERC or other recent safety guides. eLibrary users are responsible for ensuring that any activity, including practical work, which they carry out is consistent with current regulations related to Health and Safety and that they carry an appropriate risk assessment. Further information is provided in our Health and Safety guidance
Endothermic solid-solid reaction
In this demonstration or class experiment students observe an endothermic reaction between solid hydrated barium hydroxide and solid ammonium chloride. The reaction produces a liquid that evolves into ammonia gas with a dramatic drop in temperature to about –20 °C.