CHEM 121 Chapter 8 Winter 2014 1. Mixtures Heterogeneous mixture: 2 Homogeneous mixture: Solution:...
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CHEM 121 Chapter 8 Winter 2014 1
Transcript of CHEM 121 Chapter 8 Winter 2014 1. Mixtures Heterogeneous mixture: 2 Homogeneous mixture: Solution:...
CHEM 121
Chapter 8
Winter 2014
1
Mixtures
Heterogeneous mixture:
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Homogeneous mixture:
Solution:
Colloid:
SolutionsSolution =
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Solute
Solvent
Types of Solutions• Colloids:
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• Suspensions:
Solubility
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Most ionic and polar substances __________________
Most nonpolar substances _______________________
___________ can be endothermic or exothermic
Solvation• Example: NaCl
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+ - + - + -+- +-+-
+ - + - + -+- +-+-
Solubility
Amount of solute that can dissolve in a given amount of solvent
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Solubility rules p. 247
Temperature and Solubility
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•
As T increases….
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Pressure and Solubility
What dissolves?• Gases form solutions easily
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• Solids and liquids:
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Dissolving RateDifferent from solubility
How to increase dissolving rate:
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2.
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3.
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Concentration
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Weight Percent =
Volume Percent =
Weight/Volume Percent =
3-minute Practice
The amount of alcohol in a bottle of wine is labeled 13.5% (v/v). How much alcohol is in the entire 750. mL bottle?
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ppm and ppb
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Parts per million =
=
Molarity
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Molarity (M) =
What is the molarity of the solution created when you dissolve 2.5 g of NaOH in 100. mL of solution?
3-minute Practice
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How many grams of NaOH would you have to dissolve in water to make 100. mL of a 1.0 M solution?
DilutionAdd more water:
Volume?
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Concentration?Amount of solute? Number of moles of solute?
3-minute Practice
Suppose you have a 1.0 M NaOH solution, but you want a 200. mL of a 0.25 M NaOH solution. How would you make this solution?
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Aqueous Reactants
You have 250 mL of 1.0 M NaOH. How many moles NaOH?
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)(SOH)(NaOH 42 aqaq )(OH )(SONa 242 laq
How much 0.2 M H2SO4 solution would you need to completely react the NaOH?
5-minute Practice
You have: 200. mL of 2.0 M H2SO4 and
500. mL of 1.5 M NaOH
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)(SOH)(NaOH 42 aqaq )(OH )(SONa 242 laq
How much water (g) can you make?
Hints: 1.Go to moles of each2.Determine which is limiting!
Electrolytes
Electrolyte:
• Strong electrolyte:
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Weak Electrolytes and Nonelectrolytes
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• Weak electrolytes: • •
•
• Nonelectrolytes: •
)(OHC OHC 112212OH
1122122 aq(s)
Colligative PropertiesProperties that change based on dissolved concentration
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Boiling point elevation:
Freezing point depression:
Osmotic pressure:
5-minute practice
You fill a pot with 320. g of NaCl and enough water to total 1.50 L of solution.
What is the boiling point of this solution?
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MembranesSemipermeable:
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OsmosisOsmosis:
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Osmotic Pressurepressure needed to prevent net flow of solvent through a semipermeable membrane
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constant
Dialysis:
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