1. Chapter 12
Solutions

2. Classification of matter
Homogeneous
(visibly indistinguishable)
Heterogeneous
(visibly distinguishable)
(Solutions)
Mixtures
(multiple components)
Pure Substances
(one component)
Matter
Elements
Compounds

3. Solution = Solute + Solvent

4. Vodka = ethanol + water
Brass = copper + zinc

5. If solvent is water, the solution is called an aqueous solution.
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If solvent is water, the solution is called an aqueous solution.

6. Beer
Wine
Liquor
Ethanol Concentration

7. Four Concentrations
(1)
Unit: none
(2)
Unit: mol/L

8. Four Concentrations
(3)
Unit: none
Unit: none

9. Four Concentrations
(4)
Unit: mol/kg

10. A solution contains 5.0 g of toluene (C7H8) and 225 g of
benzene (C6H6) and has a density of g/mL.
Calculate the mass percent and mole fraction of C7H8, and
the molarity and molality of the solution.
2.2 %, 0.018, 0.21 mol/L, 0.24 mol/kg
Practice on Example 12.4 and
compare your results with the answers.

11. Electrical Conductivity of Aqueous Solutions

12. strong acids
strong bases
salts
strong electrolyte
weak electrolyte
nonelectrolyte
weak acids
weak bases
solute
many organic compounds

13. van’t Hoff factor nonelectrolyte: i = 1
Unit: none
nonelectrolyte: i = 1
weak electrolyte: depends on degree of dissociation
strong electrolyte: depends on chemical formula

14. NaCl
MgBr2
MgSO4
FeCl3
NaOH
Hexane
Glucose

16. Four properties of solutions
(1) Boiling point elevation
Solution compared to pure solvent
water = solvent
Boiling point = 100 °C
water + sugar = solution
Boiling point > 100 °C

17. Sugar Dissolved in Water to Make Candy Causes the Boiling Point to be Elevated

18. ∆Tb = Tb,solution − Tb,solvent = i Kb m
i: van’t Hoff factor of solute
m: molality
Kb: boiling-point elevation constant
Units
Kb is characteristic of the solvent. Does not
depend on solute.

20. Click to add notes

21. i ― electrolyte or nonelectrolyte
Boiling point elevation can be used to find molar mass of solute.
∆Tb ― experiments
i ― electrolyte or nonelectrolyte
Kb ― table or reference book

22. A solution was prepared by dissolving 18.00 g glucose in 150.0 g
water. The resulting solution was found to have a boiling point of
°C. Calculate the molar mass of glucose. Glucose is
molecular solid that is present as individual molecules in solution.
180 g/mol

23. Four properties of solutions
(1) Boiling point elevation
(2) Freezing point depression
Solution compared to pure solvent
water = solvent
freezing point = 0 °C
water + salt = solution
freezing point < 0 °C

24. ∆Tf = Tf,solvent − Tf,solution = i Kf m
i: van’t Hoff factor of solute
m: molality
Kf: freezing-point depression constant
Units
Kf is characteristic of the solvent. Does not
depend on solute.

26. Click to add notes

27. i ― electrolyte or nonelectrolyte
Freezing point depression can be used to find molar mass of solute.
∆Tf ― experiments
i ― electrolyte or nonelectrolyte
Kf ― table or reference book

28. A chemist is trying to identify a human hormone that controls
metabolism by determining its molar mass. A sample weighing
0.546 g was dissolved in 15.0 g benzene, and the freezing-point
depression was determined to be °C. Calculate the molar
mass of the hormone.
776 g/mol

29. Chapter 12, Unnumbered Figure 1, Page 535

30. The Addition of Antifreeze Lowers the Freezing Point of Water in a Car's Radiator
antifreeze = water + ethylene glycol

32. Experiment 23 this Thursday
Read the lab manual before coming to the lab
Bring the manual, a copy of the data form,
a pair of goggles, and an apron to the lab
Wash your apron before Thursday
Dress properly according to the syllabus

33. Four properties of solutions
(1) Boiling point elevation
(2) Freezing point depression
(3) Osmotic pressure

34. Osmotic Pressure

35. Π = iMRT
Π ― osmotic pressuue
M ― molarity
R ― ideal gas constant
T ― absolute temperature
i ― van’t Hoff factor of solute

36. Π = iMRT
Units
Π ― atm
M ― mol/L
R ― atm·L·K−1·mol−1
T ― K
i ― none

37. i ― electrolyte or nonelectrolyte
Osmotic pressure can be used to find molar mass of solute.
Π ― experiments
i ― electrolyte or nonelectrolyte
R ― constant
T ― experiments

38. To determine the molar mass of a certain protein, 1.00 x 10−3 g
of it was dissolved in enough water to make 1.00 mL of solution.
The osmotic pressure of this solution was found to be 1.12 torr
at 25.0 °C. Calculate the molar mass of the protein.
1.66 x 104 g/mol

39. Practice on Example 12.10 and
compare your results with the answers.

40. Figure: 13-25

41. isotonic = isosmotic: same osmotic pressure
Chapter 12, Unnumbered Figure, Page 550
isotonic = isosmotic: same osmotic pressure

42. What molarity of NaCl in water is needed to produce an
aqueous solution isotonic with blood ( Π = 7.70 atm at 25 °C)?
0.158 mol/L

43. Four properties of solutions
(1) Boiling point elevation
(2) Freezing point depression
(3) Osmotic pressure
(4) Lowering the vapor pressure

44. Nonvolatile solute to volatile solvent
Lowering Vapor Pressure

45. Liquid Surface

46. Liquid Surface pure solvent
Surface Molecules
pure solvent
number of solvent molecules above the liquid
100 x 100% x 5% = 5

47. Liquid Surface Liquid Surface pure solvent solvent + solute
number of solvent molecules above the liquid
pure solvent: 100 x 100% x 5% = 5
solution: 100 x 80% x 5% = 4

48. Four Concentrations
(3)
Unit: none
Unit: none

49. Raoult’s Law: Case 1 ― vapor pressure of solution
Nonvolatile solute in a Volatile solvent
― vapor pressure of solution
― vapor pressure of pure solvent
― mole fraction of solvent

50. For a Solution that Obeys Raoult's Law, a Plot of Psoln Versus Xsolvent, Give a Straight Line

51. Example 12.6
Calculate the vapor pressure at 25 °C of a solution containing
99.5 g of sucrose (C12H22O11) and 300 mL of water. The vapor
pressure of pure water at 25 °C is 23.8 torr. Assume the
density of water to be 1.00 g/mL.
molar mass of sucrose = g/mol
23.4 torr

53. Predict the vapor pressure of a solution prepared by mixing
35.0 g solid Na2SO4 (molar mass = 142 g/mol) with 175 g
water at 25 °C. The vapor pressure of pure water at 25 °C is
23.8 torr.

54. Liquid Surface solvent + solute
When you count the number of solute particles, use van’t Hoff factor i.

56. 22.1 torr Predict the vapor pressure of a solution prepared by mixing
35.0 g solid Na2SO4 (molar mass = 142 g/mol) with 175 g
water at 25 °C. The vapor pressure of pure water at 25 °C is
23.8 torr.
22.1 torr
Try Example 12.12

57. aqueous
solution
ΔTb
Figure: 11-21

58. Raoult’s Law: Case 2 Volatile solute in a Volatile solvent
Recall Dalton’s law of partial pressures

59. Vapor Pressure for a Solution of Two Volatile Liquids
XA + XB = 1

60. A mixture of benzene (C6H6) and toluene (C7H8) containing
1.0 mol of benzene and 2.0 mol of toluene. At 20 °C the vapor
pressures of pure benzene and toluene are 75 torr and 22 torr,
respectively. What is the vapor pressure of the mixture?
What is the mole fraction of benzene in the vapor?

62. A solution that obeys Raoult’s Law is called an
ideal solution.

63. Chapter 12, Figure 12.15A
Behavior of Nonideal Solutions

64. What kind of solution is ideal if
viewed at a molecular level?

65. pure solvent
10% P0
# of molecules in vapor = 100 x 1 x 10% = 10 χ

66. P0 χ Psln solvent + solute
15%
solvent + solute 5%
10% P0
# of molecules in vapor = 100 x 0.8 x 10% = 8 χ
Psln
Raoult’s law:
# of molecules in vapor = 100 x 0.8 x 5% = 4
Deviate from
Raoult’s law
# of molecules in vapor = 100 x 0.8 x 15% = 12

67. What kind of solution is ideal?
Solute-solute, solvent-solvent, and solute-solvent
interactions are very similar.

68. Chapter 12, Figure 12.15
Behavior of Nonideal Solutions

69. Try Example 12.7

70. What kind of solution is ideal?
Solute-solute, solvent-solvent, and solute-solvent
interactions are very similar.
Comparison to ideal gas.

71. Four Colligative properties of solutions
(1) Boiling point elevation: ∆Tb = i Kb m
(2) Freezing point depression: ∆Tf = i Kf m
(3) Osmotic pressure: Π = iMRT
(4) Lowering the vapor pressure:
Colligative: depend on the quantity (number of particles,
concentration) but not the kind or identity of the solute particles.

72. Quiz 3 Find van’t Hoff factors from formulas
Use osmotic pressure to find molar
mass of a solute
Raoult’s law, ideal solution