4. 11.29 The following phase diagram shows part of the liquid/vapor phase-transition boundaries for pure ether and a solution of a nonvolatile solute in ether.
(a) What is the approximate normal boiling point of pure ether?
(b) What is the approximate molal concentration of the solute?
[ Kb for ether is 2.02 (°C • kg) / mol.]

5. 11.30 Rank the situations represented by the following drawings according to increasing entropy.

6. 11.31 The following diagram shows a close-up view of part of the vapor-pressure curves for a solvent (red curve) and a solution of the solvent with a second liquid (green curve). Is the second liquid more volatile or less volatile than the solvent?

7. 11.32 Assume that two liquids are separated by a semipermeable membrane. Make a drawing that shows the situation after equilibrium is reached.

8. 11. 33. Assume that you are distilling a
11.33 Assume that you are distilling a 1:1 molar mixture of chloroform (CHCL3; bp = 61.7°C) and tetrachloromethane (CCL4; bp = 76.5°C). After the mixture has been heated to its boiling point and vapor has reached the top of the column, predict the approximate temperatures at the three points indicated.

9. 11.34 Two beakers, one with pure water (blue) and the other with a solution of NaCl in water (green), are placed in a closed container as represented by drawing (a). Which of the drawings (b)–(d) represents what the beakers will look like after a substantial amount of time has passed?

10. 11.35 A phase diagram of temperature versus composition for a mixture of the two volatile liquids octane (bp = 69°C) and decane (bp = 126°C) is shown. Assume that you begin with a mixture containing 0.60 mol of decane and 0.40 mol of octane.
(a)
What region on the diagram corresponds to vapor, and what region corresponds to liquid?
At what approximate temperature will the mixture begin to boil? Mark as point a on the diagram the liquid composition at the boiling point, and mark as point b the vapor composition at the boiling point.
Assume that the vapor at point b condenses and is reboiled. Mark as point c on the diagram the liquid composition of the condensed vapor and as point d on the diagram the vapor composition of the reboiled material.
(b)
(c)