ρ* *and *T* as state variables

In some cases the molar density ρ is used instead of *v*. In this case *V* is readily replaced by ρ:

(79)

And:

(80)

As in Equation (64)

(81)

and make it molar by dividing by the total number of moles *n**T*

(82)

Because *x* as well as ρ are again functions of *n*: