The problem reads: Consider a gas with constant specific heat cv and the van der waals equation of state (P+ a/v2)(v-b)=RT , where v=V/n A) Find du and the specific internal energy u=U/n B) Find ds and the specifi entropy s=S/n Here's what I've tried so far: A) I took the initial equation and subbed in the v=V/n : (P+ a/(V/n)2)(V/n-b)=RT I know that du= cvdT which can be rearranged cv = du/dT so that is where I can find the du is from the specific heat. However, I don't understand how the van der waals equation can be related mathematically to specific heat? I know that a=a measure of attraction between particles and b=the volume excluded by a mol of particles. Do I need to solve for these first? Any help is appreciated!