Using the information in Problems 7.13 and 8.20, estimate the heat of vaporization for the first bit of ethanol from ethanol-water solutions containing 25, 50, and 75 mol % ethanol and from a solution infinitely dilute in ethanol. How do these heats of vaporization compare with that for pure ethanol computed in Problem 7.13? Why is there a difference between the various heats of vaporization?

Problems 7.13.

a. The following data have been reported for the vapor pressure of ethanol as a function of temperature.

Use these data to calculate the heat of vaporization of ethanol at 17.33°C.

b. Ackermann and Rauh have measured the vapor pressure of liquid plutonium using a clever mass effusion technique. Some of their results are given here:

Estimate the heat of vaporization of liquid plutonium at 1400 K.  

 Problems 8.20.

A partial molar property of a component in a mixture may be either greater than or less than the corresponding pure-component molar property. Furthermore, the partial molar property may vary with composition in a complicated way. Show this to be the case by computing (a) the partial molar volumes and (b) the partial molar enthalpies of ethanol and water in an ethanol-water mixture. (The data that follow are from Volumes 3 and 5 of the International Critical Tables, McGraw-Hill, New York, 1929.)

Transcribed Image Text:

Pvap (kPa) T (°C) 0.6667 1.333 2.667 5.333 8.00 13.33 - 12.0 -2.3 8.0 19.0 26.0 34.9