Unformatted text preview: us with a useful formula for the entropy of an ideal gas that we will be using extensively in the future. We have δq = dU + P dV or δq/T = dU/T + P dV/T Now recall that dU = n CV dT and that T = (PV)/(Rn), which gives: δq/T = CV n dT/T + R n dV/V Assuming, for simplicity, that CV is independent of T, we get: S = ∫ δq/T = CV n ln T + R n ln V + constant Similarly, we can derive an expression for the entropy of an ideal gas as a function of P and T. Start with δ q = dU − δ W = Cv dT + PdV and write P dV = R n dT – V dP, which gives us: δq/T = ( CV +R) n dT/T  R n dP/P or S = CP n ln T  R n ln P + constant if we recall the connection between CV and CP . To write a log...
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This note was uploaded on 02/13/2014 for the course CH 353M taught by Professor Lim during the Spring '08 term at University of Texas.
 Spring '08
 LIM
 Physical chemistry, pH

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