Читать книгу Geochemistry - William M. White - Страница 53

While heat capacities at constant volume are readily measured for gases, they are difficult to measure for solids and liquids. In nature too, temperature changes tend not to take place at constant volume, so constant pressure heat capacities are of greater interest. equation 2.61 states that . Substituting this expression in to eqn. 2.66 we have:

(2.68)

Thus, enthalpy change at constant pressure may also be expressed as:

(2.69)