Chemistry - Thermochemistry - Enthalpy and enthalpy changes - Enthalpy Calculations

3 worked examples. Example 1: 'Calculate ΔH for: CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l). Given: ΔH_f°[CH₄]=-75, ΔH_f°[CO₂]=-394, ΔH_f°[H₂O]=-286 kJ/mol.' Work: ΔH = [1(-394) + 2(-286)] - [1(-75) + 2(0)] = -966 - (-75) = -891 kJ/mol. Very exothermic! (Natural gas burning). Example 2: 'Calculate ΔH for: 2