1. Chemistry 6/e Steven S. Zumdahl and Susan A. Zumdahl
Chapter 11:
PROPERTIES OF SOLUTIONS
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2. Properties of Solutions
Solution Composition
React 1
The Energies of Solution Formation
React 2
Factors Affecting Solubility
The Vapor Pressure of Solutions
React 3 • 4
Nonideal Solutions
React 5 • 6
Boiling-Point Elevation and Freezing-Point Depression
React 7 • 8 • 9
React 10 • 11
Osmotic Pressure
React 12 • 13
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3. Various Types of Solutions
Example
State of Solution
State of Solute
State of Solvent
Air, natural gas
Gas
Vodka in water, antifreeze
Liquid
Brass
Solid
Carbonated water (soda)
Seawater, sugar solution
Hydrogen in platinum
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Solution Composition
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React 1
Consider two aqueous solutions, A and B (which contain different solutes).
Is it possible for solution A to have a greater concentration than solution B in terms of mass percent, but a smaller concentration in terms of molarity? If no, explain why not. If yes, provide an example.
What if the solutions contained the same solute?
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6. The Energies of Solution Formation
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7. The Steps in the Dissolving Process
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8. The Dissolution of a Solid in a Liquid
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Solution Equilibrium
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10. Copyright © Houghton Mifflin Company. All Rights Reserved.
React 2
Refer to Figure 11.1 in your text when answering the following. In your explanations, estimate the H values of the various processes for solution formation (large or small, positive or negative), order them according to magnitude (absolute values), and explain.
a) Explain why water and oil (a long-chain hydrocarbon) do not mix.
b) Explain why two different oils (oils are long-chain hydrocarbons) will mix.
c) Explain why water and another polar liquid will mix.
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11. The Energy Terms for Various Types of Solutes and Solvents
Hsoln
Outcome
Polar solvent, polar solute
Large
Large, negative
Small
Solution forms
Polar solvent, nonpolar solute
Large, positive
No solution forms
Nonpolar solvent, nonpolar solute
Nonpolar solvent, polar solute
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Think About It
What does the term “hydrophobic” mean?
Oil is sometimes termed “hydrophobic.” Why?
Also, why is the term “hydrophobic” not really correct?
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13. Factors Affecting Solubility
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14. Factors Affecting Solubility
Structural Effects
Pressure Effects
Temperature Effects
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A Gaseous Solute
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16. The Solubilities of Several Solids as a Function of Temperature
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17. The Solubilities of Several Gases in Water
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18. The Vapor Pressure of Solutions
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19. An Aqueous Solution and Pure Water in a Closed Environment
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React 3
Consider an ideal mixture of two volatile liquids, A and B. Answer the following question. Use pictures in your explanations.
Suppose you have an equimolar mixture of A and B, and the vapor pressure of pure liquid A is twice that of pure liquid B. Determine the mole fraction of A in the vapor above the mixture.
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React 3
Consider an ideal mixture of two volatile liquids, A and B. Answer the following question. Use pictures in your explanations.
Suppose you make a mixture with twice as much A as B (in moles), and the vapor pressure of pure liquid A is twice that of pure liquid B. Determine the mole fraction of A in the vapor above the mixture.
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React 3
Consider an ideal mixture of two volatile liquids, A and B. Answer the following question. Use pictures in your explanations.
Suppose you make a mixture with twice as much B as A (in moles), and the vapor pressure of pure liquid A is twice that of pure liquid B. Determine the mole fraction of A in the vapor above the mixture.
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23. A Solution Obeying Raoult’s Law
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React 4
Benzene and toluene form ideal solutions. Imagine mixing benzene and toluene at a temperature where the vapor pressure of pure benzene is torr and the vapor pressure of toluene is torr. Consider the following:
a) You make a solution in which the mole fraction of the benzene is You then place this solution in a closed container and wait for the vapor to come into equilibrium with the solution. Then you condense the vapor. Determine the composition (mole percent) of the vapor. Explain why the relative numbers make sense.
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React 4
Benzene and toluene form ideal solutions. Imagine mixing benzene and toluene at a temperature where the vapor pressure of pure benzene is torr and the vapor pressure of toluene is torr. Consider the following:
b) You make a solution by pouring some toluene into some benzene. You then place this solution in a closed container, and wait for the vapor to come to equilibrium with the solution. Then you condense the vapor and determine the mole fraction of the toluene to be Determine the composition (mole percent) of the original solution. Explain why the relative numbers make sense.
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Nonideal Solutions
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27. Summary of the Behavior of Various Types of Solutions
Interactive Forces Between Solute (A) and Solvent (B) Particles
Hsoln
T for Solution Formation
Deviation from Raoult’s Law
Example
A  A, B  B  A  B
Zero
None (ideal solution)
Benzene-toluene
A  A, B  B < A  B
Negative (exothermic)
Positive
Negative
Acetone-water
A  A, B  B > A  B
Positive (endothermic)
Ethanol-hexane
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React 5
Would you expect each of the following solutions to be relatively ideal (with respect to Raoult’s law), to show a positive deviation, or to show a negative deviation? Explain.
a) hexane (C6H14) and chloroform (CHCl3)
b) ethyl alcohol (C2H5OH) and water
c) hexane (C6H14) and octane (C8H18)
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React 6
Would a solution with a positive deviation from Raoult’s Law have a higher or lower boiling point than ideal? Explain.
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30. Boiling-Point Elevation and Freezing-Point Depression
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31. The Development of Osmotic Pressure
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React 7
Consider two solutions. In solution A, you add 1.0 mole of table sugar to 1.0 L of water. In solution B, you add 1.0 mole of table salt to 1.0 L of water.
How do the freezing points of each solution compare to water?
How do the freezing points of each solution compare to each other?
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React 8
Why is molality (not molarity) used for colligative properties?
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React 9
You take 20.0 g of a sucrose (C12H22O11) and NaCl mixture and dissolve it in 1.0 L of water. The freezing point of this solution is found to be °C. Assuming ideal behavior, calculate the mass percent composition of the original mixture and the mole fraction of sucrose in the original mixture.
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React 10
The freezing point of an aqueous solution is –2.79°C.
a) Determine the boiling point of this solution.
b) Determine the vapor pressure (in mm Hg) of this solution at 25°C (the vapor pressure of pure water at 25°C is mm Hg).
c) Explain any assumptions you make in solving a and b.
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React 11
A plant cell has a natural concentration of 0.25 m. You immerse it in an aqueous solution with a freezing point of –0.346°C. Will the cell explode, shrivel, or neither?
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Osmotic Pressure
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Osmotic Pressure
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Osmosis
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React 12
When 33.4 mg of a compound is dissolved in 10.0 mL of water at 25°C, the solution has an osmotic pressure of 558 torr.
Calculate the molar mass of this compound.
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React 13
An aqueous solution is 1.00% NaCl by mass. Its density is g/mL at 25°C. The observed osmotic pressure of this solution is 7.83 atm at 25°C.
a) What fraction of the moles of NaCl in this solution are ion pairs?
b) Calculate the freezing point that would be observed for this solution.
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