Colligative Properties of Solutions

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Colligative Properties of Solutions

• Handout

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Colligative Properties

• Colligative Property a property that depends
  only on the amount of dissolved solute rather
  than on the chemical identity of the solute.
• Vapor pressure of a solution is lower
• Boiling point of a solution is higher
• Freezing point of a solution is lower
• Osmosis

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Examples

• Vapor pressure a nonvolatile solute lowers the
  vapor pressure of a volatile solvent.
• Freezing point when a nonvolatile solute is
  dissolved in a solvent the freezing point is
  lowered. (salt in ice)
• Boiling Point - when a nonvolatile solute is
  dissolved in a solvent the boiling point is
  increased. (salt in water)

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Molality

• molality, m moles of solute
• kilograms of solvent
• m DT / K
• or DT K m
• where K is a constant
  
• (equation for nonionizing solute)
• DT i K m
• (i is the number of different ions)

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Procedure Notes

• Check your calculation for 1 with me before
  proceeding.
• Add the salt slowly to the water or your solution
  will boil over and you will have to start over.
• Your graphs should take up a whole page. It
  should have a title and both axes should be
  labeled.
• Show all your work and include units!