Question

For all cycles in this section, assume that you have exactly 1.000 moles of gas and that the cycle is run reversibly. The known state parameters for the cycle will be given as the reduced temperature T_r ≡ T /T_c and reduced pressure P_r ≡ P/P_c, where T_c and P_c are the critical temperature and pressure of assigned diatomic molecule (N₂). Assume the gas is a diatomic van der Waals gas.

1. You have a Carnot cycle that begins with an adiabatic expansion from an initial state defined by a temperature of T_r = 1.75 and a pressure of P_r = 2.00 to a pressure of P_r = 1.75. The system then undergoes an isothermal expansion to a pressure of P_r = 1.25, followed by an adiabatic compression and then an isothermal compression back to the initial state. Calculate w, q, ∆U, ∆S, ∆S_sur, ∆H, ∆A and ∆G for each step in the cycle and for the total cycle.

(entropy S, enthalpy H, Gibbs energy G, and Helmholtz energy A.)

Answer 1