Chem 110A, F09 Problem Set 9 1. At room temperature, ethanol has an equilibrium vapor pressure of 0.0787 atm. Use this value to calculate the difference between the standard free energies of formation of liquid and gaseous ethanol at room temperature. How does your result compare with the values listed in Table 4.1? HINT: Treat the vaporization of liquid ethanol like a chemical equilibrium problem, in order to relate the standard free energy of vaporization of ethanol to the corresponding equilibrium quotient expression (i.e., the equilibrium vapor pressure). 2. At the normal boiling point (373K) of water, H vaporization = 40.7 x 10 3 J/mole, and the coexisting liquid and gas densities are 959 kg/m 3 and .590 kg/m 3 . Calculate the slope of the liquid-vapor coexistence curve, ( dP dT ) vaporization S m vap V m vap , with and without the approximation V m vap V m gas . What is the fractional error involved in making this approximation? 3.
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