Recap GCSE theories about endothermic reactions and exothermic reactions. At this point, move from using the word energy here and use enthalpy.
Find and use standard enthalpies of combustion and formation. Use these when using Hess’s laws.
Required practical 2 – Measuring an enthalpy change. Use q=m c ΔT then find the number of moles involved. There are lots to try but I always do combustion of alcohols. This way we find energy transferred, mass -> moles of alcohol burned to get enthalpy of combustion. We can then look at experimental errors and equipment inefficiencies
Use bond enthalpies to calculate the enthalpy of a reaction. This involves Hess’s law but it can be simplified, however, you need to be able to calculate any specific enthalpy. not just the overall reaction. E.g. the enthalpy of a C=O bond.