Those other forms of work

A and B, and this means allowing dS and dV to take on infinitesimal values and performing a summation, symbolized by the / symbol. This is written 

The calculation of this difference follows the reversible path shown on the USV surface - a continuous succession of equilibrium states, because that s what integration implies. However, the calculated AU is the same no matter how the change from A to B is actually carried out. 

Even though we hardly ever need to include other kinds of work in our fundamental equation, it will prove useful to have a brief look at what this equation looks like when they are included. Because many work terms don t make much sense in the molar form, we use the total energy form of the fundamental Equation (4.8). A very general formulation, including all forms of work, is 

For the tensile force and surface tension forms of work we would have 

The chemical work term that we mentioned in 3.4.1 is -Ad, where A is the affinity and is the progress variable, resulting in 

---