Problem 4 (Thermodynamic potentials, 6 pts). The energy E of a system is a function of the entropy S, volume V, and the number of particles N;E=E(S,V,N). Its total differential is dE=TdSpdV+dN a) Write the total differential dH of the enthalpy, H(S,p,N). b) Write the total differential dF of the free energy, F(T,V,N). c) Write the total differential d G of the Gibbs free energy, G(T,p,N)