Colligative Properties of Solutions Chapter 12 (continued) Colligative Properties of Solutions

Key Idea: Having solute particles present in solution (with a liquid solvent) ______ decreases the “escaping tendency” of solvent molecules Liquid molecules are less likely to “leave” the solution to: Turn into a gas (i.e., evaporate or boil) Turn into a solid (i.e., freeze) Travel across a semi-permeable membrane “stabilizes” the liquid state of the solvent (over the gaseous or solid states) Copyright © Houghton Mifflin Company. All rights reserved.

As a result, it becomes ________ Harder to escape to the gas phase Vapor pressure “lowers” VP of solution is lower than that of pure solvent Harder to boil Boiling point “elevates” Bp of solution is higher than that of pure solvent Harder to freeze Freezing point “depresses” Fp of solution is lower than that of pure solvent Copyright © Houghton Mifflin Company. All rights reserved.

Okay, so how much harder does it become? It depends on how many particles are dissolved in a given amount of solute: It depends on the concentration of dissolved particles (“Colligative” properties) Greater concentration means: More VP lowering More bp elevation More fp depression Copyright © Houghton Mifflin Company. All rights reserved.

Colligative Properties (of solutions) Dictionary.com: “(of the properties of a substance) depending on the number of molecules or atoms rather than on their nature.” Clarification: (regarding properties of a solution) depending on the concentration of dissolved particles rather on what the particles are (i.e., doesn’t depend on their size, mass, number of atoms/per particle, etc.) Copyright © Houghton Mifflin Company. All rights reserved.

http://www. chem. iastate http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/propOfSoln/colligative.html Copyright © Houghton Mifflin Company. All rights reserved.

Figure 11.10 The Presence of a Nonvolatile Solute Lowers the Vapor Pressure of the Solvent Copyright © Houghton Mifflin Company. All rights reserved.

Figure 11.14 Phase Diagrams for Pure Water (Red) and for an Aqueous Solution Containing a Nonvolatile Solute (Blues) Copyright © Houghton Mifflin Company. All rights reserved.

Sugar Dissolved in Water to Make Candy Causes the Boiling Point to be Elevated Adding Salt to Roads Prevents Ice Build-up by Lowering the Freezing Point of Water The Addition of Antifreeze Lowers the Freezing Point of Water in a Car's Radiator Copyright © Houghton Mifflin Company. All rights reserved.

Figure 11.15 (a) Ice in Equilibrium with Liquid Water (b) Ice in Equilibrium with Liquid Water Containing a Dissolved Solute Copyright © Houghton Mifflin Company. All rights reserved.

Table 11.5 Molal Boiling-Point Elevation Constants (Kb) and Freezing-Point Depression Constants (Kf) for Several Solvents Copyright © Houghton Mifflin Company. All rights reserved.

Table 11.6 Expected and Observed Values of the van't Hoff Factor for 0.05 m Solutions of Several Electrolytes Copyright © Houghton Mifflin Company. All rights reserved.

Figure 11.16 A Tube with a Bulb on the End that is Covered by a Semipermeable Membrane Copyright © Houghton Mifflin Company. All rights reserved.

Figure 11.17 Osmosis can be Prevented by Applying Pressure to the Solution Copyright © Houghton Mifflin Company. All rights reserved.

Figure 11.18 Osmotic Pressure Copyright © Houghton Mifflin Company. All rights reserved.

Red Blood Cells in Three Environments Isotonic (environment) hypertonic (environment) hypotonic (environment) Copyright © Houghton Mifflin Company. All rights reserved.

Tro’s “thirsty water” idea (Why you would dehydrate if you drank seawater) Copyright © Houghton Mifflin Company. All rights reserved.

Figure 11.19 Functioning of the Artificial Kidney Copyright © Houghton Mifflin Company. All rights reserved.

Figure 11.20 Reverse Osmosis Copyright © Houghton Mifflin Company. All rights reserved.

Figure 11.21 (b) Machinery in the desalination plant for Catalina Island Copyright © Houghton Mifflin Company. All rights reserved.

Chapter 13, Unnumbered Figure 1, Page 593

Chapter 13, Figure 13.14

Chapter 13, Unnumbered Figure 2, Page 593

Chapter 13, Unnumbered Figure 1, Page 594

Chapter 13, Unnumbered Figure 2, Page 594

Chapter 13, Unnumbered Figure 3, Page 594

Chapter 13, Unnumbered Figure 4, Page 594

Chapter 13, Unnumbered Figure 1, Page 600

Chapter 13, Unnumbered Figure 2, Page 600

Chapter 13, Table 13.8

Chapter 13, Unnumbered Figure, Page 601

Chapter 13, Unnumbered Figure, Page 602

Chapter 13, Chemistry In Your Day Figure, Page 603

Chapter 13, Figure 13.16, An Osmosis Cell

Chapter 13, Table 13.9

Chapter 13, Figure 13.17, Ion Pairing

Chapter 13, Figure 13.18, Red Blood Cells and Osmosis