Physics Help Forum Entropy as a State function

 Nov 21st 2009, 04:14 PM #1 Junior Member   Join Date: Nov 2009 Posts: 3 Entropy as a State function Here is the question i am having trouble with - Calculate the entropy of an ideal gas as a function of U, V and n at constant mole number solely by using the conditions: pV=nRT (1) U=3/2*nRT (2) dU=Tds-pdV at n=const. (3) I Have gotten to the point where I have dS=(1/T)dU+(p/T)dV+(u/T)dn I know that I need to integrate but not sure what to do from here. Any help would be greatly appreciated
 Nov 21st 2009, 11:03 PM #2 Senior Member   Join Date: Sep 2009 Location: india Posts: 409 answering this solely by mathematics(without knowing physics) dS=(dU + P dV)/T=dU/T +P/T dV=3/2 nR dT/T + nRdV/V integrating, S=3/2 nR lnT +nRlnV +C=nR ln(T^3/2V) + C

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