Colligative Properties

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Colligative Properties
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Vocabulary

• Hypotonic a cell that is placed in a solution
  and bursts.
• Raoults Law states that the magnitude of vapor
  pressure reduction is proportional to the
  solutions concentration.
• Isotonic a solution where osmosis does not
  occur
• Freezing Point - the temperature at which vapor
  pressure of solid and liquid phase are the same

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Vocabulary

• Nonvolatile a substance that will not become a
  gas under existing conditions
• Hypertonic a cell that is placed in a solution
  and shrinks
• Osmosis the net flow of molecules from less
  concentrated to more concentration solutions
• Boiling Point the temperature at which vapor
  pressure of a liquid is equal to the eternal
  pressure on its surface

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Boiling Point Elevation

• Boiling Point Elevation the boiling point of a
  liquid will be higher when another compound is
  added
• ?T Kb m i
• ?T change in temperature
• Kb boiling point constant for the solvent
• m molality (mol of solute kg of solvent)
• i number of ions in solute

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Example 1

• What is the boiling point elevation for a
  solution containing 125g of ethylene glycol
  (C2H6O2) in 1200g of water? Kb for water 0.52
  C/m
• Convert 125 g of C2H6O2 to moles.
• 2. Convert 1200 g of water to kg.
• 3. Solve for m
• 4. Plug into the formula ?T Kb m i

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Example 2

• What is the boiling point elevation for a
  solution containing 125g of salt in 600g of
  water? Kb for water 0.52 C/m
• Convert 125 g of NaCl to moles.
• 2. Convert 600 g of water to kg.
• 3. Solve for m
• 3. Plug into the formula ?T Kb m i

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Freezing Point Depression

• Freezing Point Depression - the freezing point of
  a liquid will be lower when another compound is
  added
• ?T Kf m i
• ?T change in temperature
• Kf constant for that particular solvent
• m molality (mol of solute kg of solvent)
• i number of ions in solute

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Example 1

• What is the freezing point depression when 85.3g
  of oxygen is dissolved in 1500g of water? Kf for
  water 1.86 C/m
• Convert 85.3 g of oxygen to moles.
• 2. Convert 1500 g of water to kg.
• 3. Solve for m
• 4. Plug into the formula ?T Kf m i

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Example 2

• What is the freezing point depression of a
  solution prepared by dissolving 11.3 g of
  Ca(NO3)2 in 115 g of water? Kf for water 1.86
  C/m.
• Convert 11.3 g of Ca(NO3)2 to moles.
• Convert 115 g of water to kg.
• 3. Solve for m
• 4. Plug into the formula ?T Kf m i