APChem+Colligative

Colligative Properties
The physical properties of pure liquids change when a solute is added. These changes are of interest to chemists for two reasons; they offer another window into intermolecular forces and they enable the measurement of the solute's molar mass.

A two-part assignment is described below. In part I., you will review the behavior of a pure liquid and study phase diagrams. In part II., you will practice calculations using three colligative properties.


 * || Sections in Brown LeMay || Summary of Ideas || Practice Problems to Try ||
 * Part I. || 11.5 and 11.6 || Vapor pressure is an important property of liquids, and it is described thoroughly in section 11.5. Figure 11.24 on page 426 illustrates the differences in intermolecular forces of four common chemicals. This graph is shown in a larger context in section 11.6. A phase diagram is essentially a map showing the phase of a substance at particular environmental condition (temperature and pressure). It may be helpful to read the definition of critical temperature and pressure found on page 423. || 11.37, 11.39, 11.43, 11.49, 11.51 pages 444-445 ||
 * Part II. || 13.5, pages 502-506 and 510. || Solutes have three famous effects on solvents: vapor pressure reduction, boiling point elevation, and freezing point depression. Simply put, the solute particles get in the way of solvent molecules, preventing them from leaving the solution or form a solid crystal structure. As a result, more energy than usual must be added to achieve boiling, and more energy than usual must be removed to achieve freezing. This assignment can be understood very easily by focusing on these mathematical equations: 13.7 to 13.9 (page 499), 13.10 (page 502), 13.11 (page 505), and 13.12 (page 506). Sample exercise 13.11 on page 509-510 is also valuable study material. || 13.47, 13.51, 13.55, 13.59, 13.85 pages 520 and 522 ||

You can earn two extra points on a future chemistry test. The points will be applied to the test following the Acid-Base test in February. The scheme for earning points is shown below. As usual, you must show all the work of solving a problem in order to earn full credit.
 * ~ Completed Sections ||||~ Completion Date ||
 * || Tues, 2.8 || Fri, 3.11 ||
 * Both parts of the assignment ||= 2 ||= 1 ||
 * One part of the assignment ||= 1 ||= n/a ||