Enthalpy is the heat or energy content stored in a system. The chemical symbol representing enthalpy is H. Enthalpy can be lost or gained in a system, dependant on whether the overall reaction is exothermic or endothermic. The International System of Units of enthalpy is joules. Enthalpy (H) is equal to the internal energy (U) plus the sum of the pressure (P) multiplied by volume (V); H = U + PV.
- ↑ G.J. Van Wylen and R.E. Sonntag (1985), Fundamentals of Classical Thermodynamics, Section 5.5 (3rd edition), New York, NY, John Wiley &amp;amp;amp; Sons Inc.