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 Solutions... the components of a mixture are uniformly intermingled (the mixture is homogeneous).

3. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 3 Solutions can be (Table 11.1 ) Gases Ex. Air Solids Ex. Brass Liquids Ex. Carbonated water

4. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 4 Focus of Chapter 11 is the properties of liquid solutions, particularly those containing water.

5. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 5 SOLUTION COMPOSITION SOLUTE - SUBSTANCE BEING DISSOLVED SOLVENT – DISSOLVING MEDIUM IF SOLID IN A LIQUID, THEN LIQUID IS SOLVENT IF LIQUID IN LIQUID, THE LIQUID OF LARGER AMOUNT IS SOLVENT.

6. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 6 Solution Composition 1.Molarity (M) = 2.Mass (weight) percent = 3.Mole fraction (  A ) = 4.Molality (m) =

7. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 7 IN VERY DILUTE AQUEOUS SOLUTIONS, MAGNITUDE OF MOLALITY AND MOLARITY ARE ALMOST THE SAME. MOLARITY DEPENDS ON VOLUME OF SOLUTION;  IT CHANGES SLIGHTLY WITH TEMPERATURE. MOLALITY DEPENDS ONLY ON MASS;  IT IS INDEPENDENT OF TEMPERAURE.

8. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 8 NORMALITY: EQUIVALENTS LITER OF SOL’N Equivalents 1 mole HCl provides 1 mole H + ions 1 mole H 2 SO 4 provides 2 moles H + ions

9. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 9 NORMALITY: EQUIVALENTS LITER OF SOL’N ACID-BASE RXN: EQUIVALENT = MASS OF ACID OR BASE THAT CAN FURNISH OR ACCEPT EXACTLY 1 MOLE OF PROTONS (H + IONS) EQUIVALENT MASS: MOLAR MASS # of H + or OH - IONS

10. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 10 Equivalent Mass Equivalent Mass of HCl = Molar Mass = 36.5 g/mole Equivalent Mass of H 2 SO 4 = ½ Molar Mass = ½ (98.0) = 49.0 g/mole OR 1 M HCl = 1 N HCl 1 M H 2 SO 4 = 2 N H 2 SO 4

11. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 11 Equivalent Mass of Ca(OH) 2 = ½ Molar Mass = ½ (74 g/mole) = 37 g/mole Therefore, 1 M Ca(OH) 2 = 2 N Ca(OH) 2

12. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 12 REDOX REACTIONS EQUIVALENT: QUANTITY OF OXIDIZING OR REDUCING AGENT THAT CAN ACCEPT OR FURNISH one Mole Of Electrons MnO 4 1- + 5e 1- + 8H +  Mn 2+ + 4 H 2 O EQUIV. MASS OF MnO 4 1- = 1/5 MOLAR MASS

13. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 13 Section 11.2 THE ENERGIES OF SOLUTION FORMATION SOLUBILITY: –AMOUNT OF A SUBSTANCE THAT DISSOLVES IN A GIVEN VOLUME OF SOLVENT AT A GIVEN TEMPERATURE

14. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 14 WHAT FACTORS AFFECT SOLUBILITY? GENERAL RULE: LIKE DISSOLVES LIKE POLAR SOLVENTS DISSOLVE POLAR AND IONIC SOLUTES. NONPOLAR SOLVENTS DISSOLVE NONPOLAR SOLUTES

15. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 15 Figure 11.1 The Steps in the Dissolving Process

16. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 16 Steps in Solution Formation Step 1 -Expanding the solute (endothermic) Step 2 -Expanding the solvent (endothermic) Step 3 -Allowing the solute and solvent to interact to form a solution (exothermic)  H soln =  H step 1 +  H step 2 +  H step 3 Enthalpy of Solution (  H soln )

17. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 17 Figure 11.2 The Heat of a Solution  H soln = - Energy releases  H soln = + Energy absorbed

18. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 18 NONPOLAR SOLUTE IN POLAR SOLVENT?  H 1 SMALL FOR TYPICAL NONPOLAR SOLUTE  H 3 SMALL SINCE NONPOLAR SOLUTES INTERACT VERY LITTLE WITH POLAR SOLVENT  H 2 LARGE SINCE WATER MUST OVERCOME H-BONDING THERE NOT EXPECTED TO FORM SOLUTION

19. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 19 IONIC SOLUTE IN WATER?  H 1 POSITIVE AND LARGE DUE TO IONIC FORCES  H 2 POSITIVE AND LARGE DUE TO H-BONDING  H 3 NEGATIVE AND LARGE DUE TO STRONG INTERACTIONS BETWEEN IONS AND WATER

20. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 20 NaCl IN WATER  H soln = + 3 kJ/mole WHY IS NaCl SO SOLUBLE IN WATER? PROCESSES NATURALLY RUN IN DIRECTION OF GREATER DISORDER. When dissolved  Greater disorder  Favors the process

21. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 21 Figure 11.3 Orange and Yellow Spheres

22. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 22 PROCESSES THAT REQUIRE LARGE AMOUNTS OF ENERGY TEND NOT TO OCCUR DISSOLVING NaCl REQUIRES A SMALL AMT. OF ENERGY BUT HAS A LARGE INCREASE IN DISORDER WHEN THE SOLUTE AND SOLVENT MIX

23. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 23 Solubility “LIKE DISSOLVES LIKE” There are complex driving forces for solubility. More will be discussed in Chapter 16. See Table 11.3.