Enthalpy
A thermodynamic potential defined as internal energy plus the product of pressure and volume, representing total heat content under constant pressure conditions.
Governing formula
H = U + P V, ΔH = Q_p
SI unit
J
In depth
In constant-pressure processes, enthalpy change ΔH equals the heat transferred to or from the system, making enthalpy essential for chemical reaction energy accounting.
Examples in the real world
Endothermic chemical reactions absorbing enthalpy (+ΔH) from surroundings, or combustion releasing exothermic enthalpy (-ΔH).