Westminster H.S. AP Chemistry Name ____________________________________Period ___ Date ___/___/___

11 Properties of SolutionsC O L L I G A T I V E P R O P E R T I E S

A. Colligative Properties1. Properties dependent on the ____________ of solute particles but not on their ________________.

a. Boiling-Point elevationb. Freezing-Point depressionc. Osmotic Pressure

B. Boiling-Point Elevation1. Nonvolatile solutes elevate the boiling point of the solvent.

ΔT = Kbmsolute

a. ΔT is the boiling-point elevationb. Kb is the molal boiling-point elevation constant of the solventc. msolute is the molality of the solute in the solution

C. Freezing-Point Depression1. Dissolved solutes depress the freezing point of the solvent

ΔT = Kfmsolute

a. ΔT is the freezing-point depressionb. Kf is the molal freezing-point depression constant of the solventc. msolute is the molality of the solute in the solution

D. Osmosis

1. The flow of solvent molecules into a solution through a semipermeable membrane.E. Osmotic Pressure

1. The pressure necessary to keep water from flowing across a semipermeable membrane.2. Osmotic pressure can be used to characterize solutions and determine molar masses

Π = MRTa. Π is osmotic pressure in atmospheresb. M is molarity of the solutionc. R is the gas law constantd. T is the Kelvin temperature

F. Dialysis1. Transfer of solvent molecules as well as small solute molecules and ions

G. Isotonic Solutions1. Solutions that have the same osmotic pressure

H. Osmotic Pressure and Living Cells1. Crenation

a. Cells placed in a hypertonic solution (having an osmotic pressure ______________ than that of cell fluids) lose water to the solution and shrink.

2. Hemolysis

a. Cells placed in a hypotonic solution (having an osmotic pressure ______________ than that of cell fluids) gain water from the solution and swell, possibly bursting.

I. Reverse Osmosis1. External pressure applied to a solution can cause water to leave the solution

a. Concentrates impurities (such as salt) in the remaining solution.b. Pure solvent (such as water) is recovered on the other side of the semipermeable membrane.