1. 14 Solutions Brass, a solid solution of Zn and Cu, is used to make
musical instruments and many other objects.
Foundations of College Chemistry, 15th Ed.
Morris Hein, Susan Arena, and Cary Willard
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2. Copyright © 2016 John Wiley & Sons, Inc. All rights reserved.
Chapter Outline
14.1 General Properties of Solutions
14.2 Solubility
14.3 Rate of Dissolving Solids
14.4 Concentration of Solutions
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3. General Properties of Solutions
Solution: a homogeneous mixture of one or more
solutes and a solvent.
Solute: substance being dissolved.
Solvent: dissolving agent that is usually the
most abundant substance in the mixture.
Note: a solution does not always just refer to liquids.
Example: Air is a solution composed of N2, O2, Ar and CO2
N2 is the solvent as it composes 78% of air.
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4. Solutions Practice Soda is a mixture of sugar in water.
Which substance is the solute?
a. sugar
b. water
c. soda
A solution is prepared by adding 25 mL of ethyl alcohol
to 75 mL of water. Which substance is the solvent?
a. ethyl alcohol
b. water
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5. Common Types of Solutions
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6. Properties of a True Solution
A homogeneous mixture of two or more components
whose ratio can be varied.
2. The dissolved solute is molecule or ionic in size
(< 1 nm).
Can be colored or colorless, though solutions are
usually transparent.
4. The solute remains dissolved and does not settle
(precipitate) out of solution over time.
The solute can be separated from solvent by physical
means (usually evaporation).
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7. Solubility Solubility: the amount of a substance that will dissolve
in a specific amount of solvent at a given temperature.
Example g KBr/100g H2O at 23 ºC
Miscible: when two liquids dissolve in each other.
Immiscible: when two liquids do not dissolve one another.
A mixture of oil and water is immiscible.
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8. Copyright © 2016 John Wiley & Sons, Inc. All rights reserved.
Solubility Rules
Soluble
Insoluble
Na+, K+, NH4+
Nitrates (NO3-)
Acetates, (C2H3O2-)
Except
Cl-, Br-, I-
Ag+, Hg22+, Pb2+
Sulfates (SO42-),
Ag+, Ca2+ (slightly)
Except
Ba2+, Sr2+, Pb2+
Carbonates (CO32-)
Phosphates (PO43-)
OH-, Sulfides (S2-)
Except
NH4+, Group I
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9. Solutions Practice Predict the solubility of barium sulfate.
a. soluble
b. insoluble
Most sulfates are soluble, except Ba2+.
Predict the solubility of NaCl.
a. soluble
b. insoluble
All Na+ salts are soluble.
Copyright © 2016 John Wiley & Sons, Inc. All rights reserved.

10. Solutions Practice Predict the solubility of silver nitrate.
a. soluble
b. insoluble
All NO3- salts are soluble.
Predict the solubility of silver hydroxide.
a. soluble
b. insoluble
Most hydroxides are insoluble.
Predict the solubility of ammonium carbonate.
a. soluble
b. insoluble
All NH4+ salts are soluble.
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11. Factors Affecting Solubility
“Like Dissolves Like”
Polar compounds dissolve in polar solvents.
Ethanol (CH3OH) dissolves in water (HOH).
Nonpolar compounds dissolve in nonpolar solvents.
Carbon tetrachloride (CCl4) dissolves in
hexanes (CH3(CH2)4CH3).
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12. Factors Affecting Solubility
Ionic Compound Solubility in Polar Solvents
Several ionic compounds dissolve in water,
due to strong ion-dipole forces.
The individual cations and anions are surrounded
by H2O molecules (i.e., hydrated).
The cation is attracted to the partially negative O atom.
The anion is attracted to the partially positive H atoms.
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13. Temperature and Solubility
Solubility increases with temperature for most solids (red lines)
Solubility decreases with temperature for all gases (blue lines).
As a gas increases in temperature, the kinetic energy
increases, which means it interacts less with the liquid,
making it less easy to solvate.
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14. Pressure and Solubility
Pressure does not affect solubility of liquids or solids.
Gas solubility in a liquid is proportional to
the gas pressure over the liquid.
: A bottle of root beer is under high pressure.
Example
As the bottle opens, the pressure decreases,
and the bubbles formed indicate gas loss from the liquid.
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15. Saturated and Unsaturated Solutions
There are limits to the solubility of a compound
at a given temperature.
Saturated solutions: contain the maximum amount
of dissolved solute in a solvent.
Saturated solutions are still dynamic; dissolved solute
is in equilibrium with undissolved solute.
undissolved solute dissolved solute
Unsaturated solutions: contain less than the maximum
amount of possible dissolved solute in a solvent.
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16. Supersaturated Solutions
Supersaturated solutions: contain more solute than
needed to saturate a solution at a given temperature.
How is this possible?
Heating a solution can allow more to dissolve.
Upon cooling to ambient temperature,
the solution is supersaturated.
These solutions are unstable -- disturbing the solutions
can cause precipitation of solute.
Some hotpacks release heat by crystallization of a supersaturated solution of sodium acetate.
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17. Solubility Practice Will a solution prepared by adding 9.0 g of KCl to
20.0 g of H2O be saturated or unsaturated at 20 ºC?
Using Table 14.3, 34.0 g of KCl will dissolve
in g of H2O at 20 ºC.
6.8 g of KCl will then dissolve in
20.0 g of water at that temperature.
The KCl solution should be saturated.
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18. Rate of Dissolving Solids
Effect of Particle Size
A solid can only dissolve at a surface that
is in contact with the solvent.
Since smaller crystals have a higher surface to volume
area, smaller crystals dissolve faster than larger ones.
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19. Rate of Dissolving Solids
Effect of Temperature
Increasing the temperature normally increases the rate
of dissolution of most compounds.
Solvent molecules strike the solid surface more often,
causing the solid to dissolve more rapidly.
The solute molecules are more easily separate from the solid due to a higher kinetic energy.
Copyright © 2016 John Wiley & Sons, Inc. All rights reserved.

20. Rate of Dissolving Solids
Effect of Solute Concentration
Rate is highest at higher concentration and
decreases at lower concentration.
As the solution approaches the saturation point,
the rate of solute dissolving decreases.
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21. Rate of Dissolving Solids
Effect of Agitation/Stirring
Stirring a solution briskly breaks up a solid
into smaller pieces, increasing surface area,
thereby increasing the rate of dissolution.
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22. Surface Area Surface Area of Two Crystals
Surface area = 6(side)2 = 6(0.1)2 = 0.06 cm2
1000 cubes have a total surface area of
1000 x 0.06 cm2 = 60 cm2
What is the surface area of a 1 cm square crystal?
Surface area = 6(side)2 = 6(1)2 = 6 cm2
Copyright © 2016 John Wiley & Sons, Inc. All rights reserved.

23. Solutions: A Reaction Medium
The purpose of dissolving reactants in a solution is
often to allow them to come in close contact to react.
Example:
Solid-solid reactions are generally very slow
at ambient temperature
KCl (s) + AgNO3 (s) No Reaction
By dissolving both compounds in water,
the ions can collide with one another and react
to form an insoluble compound.
KCl (aq) + AgNO3 (aq) AgCl (s) + KNO3 (aq)
K+(aq) + Cl-(aq) + Ag+(aq) + NO3-(aq) AgCl(s) + K+(aq) + NO3-(aq)
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24. Concentration of Solutions
Qualitative Expressions of Concentrations
Dilute: a solution that contains a relatively small
amount of dissolved solute.
Example:
A 0.1 M HCl solution is dilute acid.
Concentrated: a solution that contains a relatively large
amount of dissolved solute.
Example:
A 12 M HCl solution is concentrated acid.
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25. Quantitative Expressions of Concentrations:
Concentration of Solutions
Quantitative Expressions of Concentrations:
Units
Symbol
Definition
Mass percent
% m/m
Part per million
ppm
Mass/Volume percent
% m/v
Volume percent
% v/v
Molarity M
Molality m
mass solute
mass solution
x 100
mass solute
mass solution
x 1,000,000
mass solute
mL solution
x 100
mL solute
mL solution
x 100
mol solute
L solution
mol solute
kg solvent
Copyright © 2016 John Wiley & Sons, Inc. All rights reserved.

26. Mass Percent-Fair Test Question
Calculate the mass % of NaCl in a solution prepared
by dissolving 50.0 g of NaCl in g of H2O.
Knowns
50.0 g NaCl (solute mass)
150.0 g H2O (solvent mass)
200.0 g solution (solute + solvent mass)
Formula
mass solute
mass solution
mass % =
x 100
Calculate
50 g NaCl
200 g soln
mass % =
x 100 = 25% NaCl
Copyright © 2016 John Wiley & Sons, Inc. All rights reserved.

27. Mass Percent Practice What is the mass of Na2CO3 needed to make
350.0 g of a 12.3% aqueous solution?
Knowns
12.3% solution (mass %)
350.0 g solution (solute + solvent mass)
Solve for mass of solute (Na2CO3)
Formula
mass % x mass soln
100
mass solute
mass solution
mass % =
x 100
mass solute =
Calculate
12.3 x g
100
mass solute =
= 43.1 g Na2CO3
Copyright © 2016 John Wiley & Sons, Inc. All rights reserved.

28. Mass-Volume Percent-Fair Test Question
What is the mass volume percent NaCl solution that contains .450 g of NaCl in 50.0 mL of solution?
Knowns
.450 g NaCl
50.0 mL solution (solution volume)
Formula
g solute
mL solution
m/v % =
x 100
Calculate
.450 g NaCl
50 mL
m/v % =
= %
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29. Mass-Volume Percent Saline is a 0.9 m/v % NaCl solution. What mass of
sodium chloride is needed to make 50 mL of saline?
Knowns
50.0 mL solution (solution volume)
0.90 m/v% (mass/volume %)
Solve for mass of solute (NaCl)
Formula
g solute
mL solution
m/v % x mL soln
100
m/v % =
x 100
mass solute =
Calculate
50.0 x 0.90
100
mass solute =
= 0.45 g NaCl
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30. Mass-Volume Percent Practice
What volume of a 3.0% H2O2 solution
will contain 10.0 g of H2O2?
a mL soln
b mL soln
c L soln
d. 165 mL soln
Knowns
10.0 g H2O2 (desired solute mass)
3.0 m/v%
Solve for volume of solution
Formula
g solute
mL solution
mL solution =
g solute
m/v %
x 100
m/v % =
x 100
Calculate
10.0 g
3.0
mass solute =
x 100
= 330. mL sln
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31. Volume Percent-Fair Test Question
What volume % of soda that contains mL of ethanol (CH3CH2OH) in 3300 mL solution?
Knowns
200.0 mL ethanol (solute volume)
3300 mL (volume of solution)
Formula
volume solute
volume solution
volume % =
x 100
Calculate
200.0 mL
3300 mL
volume % =
x 100
= 6.1%
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32. Volume Percent Practice
A solution is prepared by mixing 20.0 mL of propanol
with enough water to produce mL of solution.
What is the volume percent of propanol?
a %
b %
c %
d %
Knowns
20.0 mL propanol (solute volume)
400.0 mL solution (solution volume)
Solve for volume percent
Formula
volume solute
volume solution
volume % =
x 100
Calculate
20.0
400.0
volume % =
x 100
= 5.00% propanol
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33. A common unit for solution concentration dissolved in enough water to
Molarity
A common unit for solution concentration
due to convenience.
mol solute
L solution
molarity =
Example:
To prepare a 1.0 M KCl
solution, 1.0 mol of KCl is
dissolved in enough water to
make 1.0 L of solution.
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34. Molarity Practice Calculate the molarity of a solution prepared by
dissolving 9.35 g of KCl in enough water to
prepare a mL solution.
Knowns
9.35 g KCl (solute mass)
250.0 mL solution (solution volume)
mol solute
L solution
Formula
Solve for molarity
molarity =
Calculate
1 mol KCl
9.35 g KCl x
= mol KCl
g KCl
0.125 mol KCl
molarity =
= M KCl
0.250 L solution
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35. How many grams of KOH are required to prepare
Molarity Practice
How many grams of KOH are required to prepare
600.0 mL of a M KOH solution?
a g KOH
b g KOH
c x 104 g KOH
d g KOH
Knowns
600 mL (solution volume)
0.450 M (solution molarity)
Plan
Solve for moles, then grams using molarity and
molar mass as conversion factors
mol solute
L solution
Formula
molarity =
mol solute =
molarity x L soln
Calculate
moles solute = M KOH x L = mol KOH
56.11 g KOH
0.270 mol KOH x
= 15.1 g KOH
1 mol KOH
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36. Dilution Dilution: Adding a solvent to a concentrated solution to
make the solution less concentrated (i.e. dilute).
When a solution is diluted, only the volume changes. The number of moles of solute remains constant.
moles before dilution = moles after dilution
Molarity1 x Volume1 = Molarity2 x Volume2
M1 × V1 = M2 × V2
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37. What volume of 12 M HCl is needed to make
Dilution Practice
What volume of 12 M HCl is needed to make
500.0 mL of a 0.10 M HCl?
Knowns
12 M HCl M1
0.10 M HCl M2
500.0 mL V2
Solving for:
volume of 12 M HCl V1
M1 × V1 = M2 × V2
Calculate
V2M2 M1
500 mL x 0.10 M
12 M
V1 = =
= 4.2 mL
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38. Dilution Practice
Calculate the molarity of a NaOH solution prepared by
mixing 100. mL of 0.20 M NaOH with 150 mL of H2O.
a. 2.0 M NaOH
b M NaOH
c M NaOH
d M NaOH
Knowns
0.20 M NaOH M1
100 mL sln V1
= 250 mL V2
Solving for:
molarity NaOH M2
M1 × V1 = M2 × V2
Calculate
M1V1 V2
0.20 M x 100 mL
250 mL
M2 = =
= M NaOH
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39. Learning Objectives 14.1 General Properties of Solutions
List the properties of a true solution
14.2 Solubility
Define solubility and the factors that affect it.
14.3 Rate of Dissolving Solids
Describe the factors that affect the rate
at which a solid dissolves.
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40. Learning Objectives 14.4 Concentrations of Solutions .
Solve problems involving mass percent, volume percent,
molarity, and dilution. .
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