Question: In the system A + B, activity coefficients can be expressed by the one-parameter Margules equation with A12 = 0.5. The vapor pressures of A and B at 80oC are PAsat = 900 mmHg, PBsat = 600 mmHg. Is there an azeotrope in this system at 80oC, and if so, what is the azeotrope pressure and composition?

Prompt/Given Information: Consider a reversible isothermal expansion of vapor benzene at 450 K from 1 to 0.1 MPa. Assume that the PVT behavior of benzene obeys van der Waals equation of state.                                      P = (RT)/(V - b) - a/V2            for benzene: a = 1884514 (cm6 * MPa)/mol2 and                                  b = 119.47 cm3/mol For your convenience, at 450 K and 0.1 MPa the volume of vapor benzene is 37025 cm3/mol, and at 450 K and 1 MPa it is 3312.4 cm3/mol. R = 8.314 (MPa*cm3)/(mol*K). Note: 1 cm3*MPa/mol = 1 J/mol   Question: Calculate the work done to the system? Calculate the work for the system if the gas was ideal?

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Prompt/Given Information: Consider a reversible isothermal expansion of vapor benzene at 450 K from 1 to 0.1 MPa. Assume that the PVT behavior of benzene obeys van der Waals equation of state.                                      P = (RT)/(V - b) - a/V2            for benzene: a = 1884514 (cm6 * MPa)/mol2 and                                  b = 119.47 cm3/mol For your convenience, at 450 K and 0.1 MPa the volume of vapor benzene is 37025 cm3/mol, and at 450 K and 1 MPa it is 3312.4 cm3/mol. R = 8.314 (MPa*cm3)/(mol*K). Note: 1 cm3*MPa/mol = 1 J/mol   Question: What is the change of internal energy? What would be the change of internal energy if the gas was ideal?