Chapter 12 Section 3 Concentration of Solutions p' 418424

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SolutionsChapter 12 Modern Chemistry
Sections 1-3 Types of Mixtures The Solution
Process Concentrations of Solution
Chapter 12 Section 3 Concentration of Solutions
p. 418-424
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Section 12.3
Concentration of Solutions
Chapter 12 Section 3 Concentration of Solns p.
418-424
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Vocabulary
Concentration Concentrated Dilute Molarity
Molality Dilution
Chapter 12 Section 3 Concentration of Solns p.
418-424
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DILUTE
CONCENTRATED
CONCENTRATION
MOLARITY
MOLALITY
DILUTIONS
Concept Map 12.3
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Concentration

• Concentration is a measure of the amount of
  solute in a given amount of solvent or solution.
• Dilute means that there is a small amount of
  solute.
• Concentrated means that there is a large amount
  of solute.
• There are many ways to quantify concentration.

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Concentration Units
Chapter 12 Section 3 Concentration of Solns p.
418-424
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Molarity
The number of moles of solute in one liter of
solution.
moles of solute
M
liters of solution
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Making a Molar Solution
Chapter 12 Section 3 Concentration of Solns p.
418-424
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p. 419
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Molarity Sample Problems

• You have 3.50 L of solution that contains 90.0 g
  of sodium chloride, NaCl. What is the molarity of
  that solution?
• You have 0.8 L of a 0.5 M HCl solution. How many
  moles of HCl does this solution contain?
• To produce 40.0 g of silver chromate, you will
  need at least 23.4 g of potassium chromate in
  solution as a reactant. All you have on hand is 5
  L of a 6.0 M K2CrO4 solution. What volume of the
  solution is needed to give you the 23.4 g K2CrO4
  needed for the reaction?

1. 0.440 M NaCl
2. 0.4 mol HCl
p. 420-421
3. 0.020 L K2CrO4
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Molarity Practice Problems

• What is the molarity of a solution composed of
  5.85 g of potassium iodide, KI, dissolved in
  enough water to make 0.125 L of solution?
• How many moles of H2SO4 are present in 0.500 L of
  a 0.150 M H2SO4 solution?
• What volume of 3.00 M NaCl is needed for a
  reaction that requires 146.3 g of NaCl?

1. 0.282 M KI
2. 0.0750 mol
p. 421
3. 0.834 L
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Molality
The number of moles of solute per kilogram of
solvent.
moles of solute
m
kilograms of solvent
The density of water is 1 g / mL. So, 1 g 1 mL
and 1kg 1 L
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Making a Molal Solution
Chapter 12 Section 3 Concentration of Solns p.
418-424
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p. 422
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Molality Sample Problems

• A solution was prepared by dissolving 17.1 g of
  sucrose (table sugar, C12H22O11) in 125 g of
  water. Find the molal concentration of this
  solution.
• A solution of iodine, I2, in carbon
  tetrachloride, CCl4, is used when iodine is
  needed for certain chemical tests. How much
  iodine must be added to prepare a 0.480 m
  solution of iodine in CCl4 if 100.0 g of CCl4 is
  used?

1. 0.400 m C12H22O11
p. 423-424
2. 12.2 g I2
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Molality Practice Problems

• What is the molality of acetone in a solution
  composed of 255 g of acetone, (CH3)2CO, dissolved
  in 200. g of water?
• What quantity, in grams, of methanol, CH3OH, is
  required to prepare a 0.244 m solution in 400. g
  of water?

1. 22.0 m acetone
2. 3.13 g CH3OH
p. 424
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Diluting a Solution
How much of an original solution is needed to
make a less concentrated solution by adding water?
M1 V1 M2 V2
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Dilution Problems
P. 902 367. What is the molarity of a solution
of ammonium chloride prepared by diluting 50.00
mL of a 3.79 M NH4Cl solution to 2.00 L? P. 903
370. To what volume should 1.19 mL of an 8.00 M
acetic acid solution be diluted in order to
obtain a final solution that is 1.50 M?
0.0948 M
6.35 mL
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Dilution Problems
P. 903 371. What volume of a 5.75 M formic
acid solution should be used to prepare 2.00 L of
a 1.00 M formic acid solution? P. 903 372. A
25.00 mL sample of ammonium nitrate solution
produces a 0.186 M solution when diluted with
50.00 mL of water. What is the molarity of the
stock solution?
348 mL
0.558 M
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Ch 12 Sec 3 Homework
Molarity, Molality, Dilution Problem Bank Page
902-903 345-347, 350-352, 375
Chapter 12 Section 3 Concentration of Solns p.
418-424
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