Use the formula: H = U + PV
Identify the internal energy, pressure, and volume
For a process, calculate the change in enthalpy: ΔH = ΔU + PΔV
At constant pressure, use: ΔH = q_p
For reactions, use: ΔH = ΣH(products) – ΣH(reactants)
Use standard enthalpies of formation: ΔH°rxn = ΣnΔH°f(products) – ΣnΔH°f(reactants)
Use Hess’s law to add known enthalpy changes
Use calorimetry if heat transfer is measured: q = mcΔT
Convert units consistently before calculating
Report the final answer in kJ or J as required