Proving (dU/dV)T=0 and (dH/dP)T=0 for ideal gases

[Hong1111]

How to prove that

(a)(dU/dV)_T=0
(b)(dH/dP)_T=0

for an ideal gas.

Where U is internal energy per unit mass, V is volume, T is temperature (which is held constant for above 2 question), H is the enthalpy per unit mass, and P is the pressure.

I found this in a thermodynamics textbook. This is not a homework question. I just want to know how does this apply to ideal gas and how to derive the both equations. And in the end, I got warning from moderator.

Thanks.

 

[physman55]

For an ideal gas you should find that the internal energy is only a function of T, hence dU/dV is definitely zero.

Same applies for the enthalpy, define H = U + PV, use the ideal gas equation to substitute for PV and you'll see that H is only a function of T as well, so dH/dP is zero.

I don't see the point of those equations though =/