Question

Consider a collection of N indistinguishable molecules with only two energy levels:

E₂ = E _________________ g = 4

E₁ = 0 _________________ g = 2

Derive an expression for S, the entropy of this system. Be sure to indicate clearly all of the important steps in the derivation.

Answer 1

H = E + PV delta H = delta E + P delta V + V delta P G = H - Ts delta G = delta H - T delta s - s delta T delta G = delta E + P delta V + V delta P - T delta S - s delta T (4 - 2) = (E - 0) + P delta V + V delta P - T delta S - S delta T 2 = E + P delta V + V delta P + T delta S + S delta T 2 = H - TS TS = H - 2 S = H - 2/T