Problem 11.12:

a) Assuming that methanol (1), ethanol (2), acetonitrile (3), and nitromethane (4), form ideal solutions, calculate the bubble and dew pressure at 120 °C of a mixture that contains equal moles of each of the four components.

b) What is the phase of this mixture at 1 bar, 120 °C?

Additional data: the saturation pressures are: P1 = 6.43239 bar, P2 = 4.34246 bar, P3 = 3.02411 bar, P4 = 1.75725 bar.

Problem 11.13: The exhaust stream from a combustion process contains 10% water vapor (by mol). The pressure of the stream is 2 bar and the temperature 100 °C.

a) What is the relative humidity of the stream?

b) What is its dew temperature?

c) The stream is to be cooled to 25 °C at constant pressure. To avoid condensation, the exhaust stream is mixed with dry air prior to cooling. How much air is needed? Report the result in moles of dry air per mole of gas.