Chapter 11, Problem 13PS

Answer the following questions using Figure 11.12:

1. (a) What is the approximate equilibrium vapor pressure of water at 60 °C? Compare your answer with the data in Appendix G.
2. (b) At what temperature does water have an equilibrium vapor pressure of 600 mm Hg?
3. (c) Compare the equilibrium vapor pressures of water and ethanol at 70 °C. Which is higher?

Figure 11.12 Vapor pressure curves for diethyl ether [(C₂H₃)₂O], ethanol (C₂H₅OH), and water. Each curve represents conditions of T and P of which the two phases, liquid and vapor, are in equilibrium. These compounds exist as liquids for temperatures and pressures to the left of the curve and as gases under conditions to the right of the curve. (See Appendix G for vapor pressures for water of various temperatures.)