1. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 1 Chemistry FIFTH EDITION Chapter 11 Properties of Solutions http://www2.fultonschools.org/teacher/warrene/AP%20Chemistry.htm http://www2.fultonschools.org/teacher/warrene/AP%20Chemistry.htm

2. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 2 Section 11.3 Factors Affecting Solubility STRUCTURE EFFECTS -- “LIKE DISSOLVES LIKE” -- SOLUBILITY IS FAVORED IF SOLUTE AND SOLVENT HAVE SIMILAR POLARITIES. -- POLARITY DETERMINED BY MOLECULAR STRUCTURE

3. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 3 PRESSURE EFFECTS PRESSURE HAS --- LITTLE EFFECT ON SOLUBILITY OF SOLIDS AND LIQUIDS --- SIGNIFICANTLY INCREASES SOLUBILITY OF A GAS

4. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 4 Figure 11.5 A Gaseous Solute

5. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 5 Henry’s Law P = kC P = partial pressure of gaseous solute above the solution C = concentration of dissolved gas k = a constant The amount of a gas dissolved in a solution is directly proportional to the pressure of the gas above the solution.

6. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 6 HENRY’S LAW HOLDS FOR DILUTE SOLUTIONS OF GASES THAT DO NOT DISSOCIATE IN OR REACT WITH THE SOLVENT. Homework

7. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 7 TEMPERATURE EFFECTS SOLUBILITY OF MOST SOLIDS IN WATER INCREASES WITH TEMPERATURE. SOLUBILITY OF SOME SOLIDS IN WATER DECREASE WITH TEMPERATURE.

8. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 8 Figure 11.6 The Solubilities of Several Solids as a Function of Temperature

9. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 9 SOLUBILITY OF GASES IN WATER DECREASES WITH INCREASING TEMPERATURE.

10. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 10 Figure 11.7 The Solubilities of Several Gases in Water

11. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 11

12. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 12 Section 11.4 VAPOR PRESSURE OF SOLUTIONS SOLUTE’S EFFECT ON THE SOLVENT 1. A NON-VOLATILE SOLUTE HAS NO TENDENCY TO ESCAPE FROM THE SOLUTION INTO THE VAPOR PHASE. 2. A NON-VOLATILE SOLUTE REDUCES THE TENDENCY OF SOLVENT MOLECULES TO ESCAPE.

13. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 13 Figure 11.10 The Presence of a Nonvolatile Solute Inhibits the Escape of Solvent Molecules from the Liquid

14. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 14 Raoult’s Law P soln =  solvent P  solvent P soln = vapor pressure of the solution  solvent = mole fraction of the solvent P  solvent = vapor pressure of the pure solvent The presence of a nonvolatile solute lowers the vapor pressure of a solvent.

15. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 15 Figure 11.11 A Solution Obeying Raoult’s Law P soln = χ solvent P  solvent y = m x + b

16. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 16 LIQUID – LIQUID SOLUTIONS -- TWO VOLATILE LIQUID COMPONENTS -- BOTH CONTRIBUTE TO THE TOTAL VAPOR PRESSURE IDEAL SOLUTION: OBEYS RAOULT’S LAW MODIFIED RAOULT’S LAW: P TOTAL = P A + P B =  A P ° A +  B P ° B

17. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 17 Figure 11.12 Total Vapor Pressure of a Solution

18. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 18 NEARLY IDEAL SOLUTIONS WHEN SOLUTE-SOLUTE, SOLVENT-SOLVENT, & SOLUTE-SOLVENT INTERACTIONS ARE VERY SIMILAR.

19. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 19 NON-IDEAL SOLUTIONS NEGATIVE DEVIATIONS SOLVENT HAS SPECIAL AFFINITY FOR SOLUTE TENDENCY OF SOLVENT MOLECULES TO ESCAPE IS LOWERED  H SOL’N IS LARGE & NEGATIVE STRONG INTERACTION BETWEEN SOLUTE AND SOLVENT (Ex. – H bonding)

20. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 20 NON-IDEAL SOLUTIONS POSITIVE DEVIATIONS WEAK SOLUTE/SOLVENT INTERACTIONS  H SOL’N = POSITIVE MOLECULES HAVE HIGHER TENDENCY TO ESCAPE

21. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 21 IDEAL SOLUTIONS SOLUTIONS OF SIMILAR LIQUIDS  H SOL’N = approx. Zero

22. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 22 Figure 11.13 Vapor Pressure for a Solution of Two Volatile Liquids Ideal Positive Deviation; P total is larger Negative Deviation; P total is smaller