Chemistry 157 – Energy Enthalpy and Thermochemistry : Enthalpy , a property of a thermodynamic system, is equal to the system’s internal energy plus the product of its pressure and volume.[ In a system enclosed so as to prevent matter transfer, for processes at constant pressure, the heat absorbed or released equals the change in enthalpy.
The unit of measurement for enthalpy in the International System of Units (SI) is the joule. Other historical conventional units still in use include the British thermal unit (BTU) and the calorie.
Contents • 9.1 The Nature of energy • 9.2 Enthalpy • 9.3 Thermodynamics of Ideal Gases • 9.4 Calorimetry • 9.5 Hess’s Law • 9.6 Standard Enthalpies of Formation • 9.7 Present Sources of Energy • 9.8 New Energy Sources