Physical Chemistry Lesson of the Day – Enthalpy
January 10, 2014 Leave a comment
The enthalpy of a system is the system’s internal energy plus the product of the pressure and the volume of the system.
Just like internal energy, the enthalpy of a system cannot be measured, but a change in enthalpy can be measured. Suppose that the only type of work that can be performed on the system is pressure-volume work; this is a realistic assumption in many chemical reactions that occur in a beaker, a flask, or any container that is open to the constant pressure of the atmosphere. Then, the change in enthalpy of a system is the change in internal energy plus the pressure-volume work done on the system.