a) Show that the Helmholtz potential of a mixture of simple ideal gases is the sum of the Helmholtz potentials of each individual gas:
F(T,V,N1,…,Nr)=F(T,V,N1)+⋯+F(T,V,Nr)
Recall the fundamental equation of the mixture, as given in equation 3.40.
An analogous additivity does not hold for any other potential expressed in terms of its natural variables.