Two moles of an ideal gas (C v,m = 1.5R) is subjected to the following changes in states: A (500 K, 5 bar) →(Reversible Isothermal Expansion) B →(Isochoric Cooling) C (250 K, 1 bar) →(Single stage adi

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Two moles of an ideal gas (C v,m = 1.5R) is subjected to the following changes in states: A (500 K, 5 bar) →(Reversible Isothermal Expansion) B →(Isochoric Cooling) C (250 K, 1 bar) →(Single stage adiabatic compression) D (3 bar) The correct statement(s) is/are

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B to C is at constant V, so P B /T B = P C /T C gives P B = 1 × 500/250 = 2 bar: (a) true. For C to D, the single-stage compression is against P ext = 3 bar, q = 0: nC v (T D - 250) = -P ext (V D - V C ). V C = 2R(250)/1 = 500R, V D = 2RT D /3. So 3R(T D - 250) = -2RT D + 1500R, 5T D = 2250, T D = 450 K: (b) true. Δ H CD = 2(2.5R)(200) = 1000R: (c) true. Δ U BC = 2(1.5R)(-250) = -750R, not 375R: (d) false. Ans: (a), (b), (c).

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