Osmotic Pressure•The net movement of solvent is always toward thesolution with the higher solute concentration.•The flow of solvent to the solution increases theheight of the column. The column exerts pressureon the membrane to cause more solvent particlesin the solution to pass to the pure solvent side.When the rate of flow ofsolvent particles are inequilibrium between thetwo sides the volume ofthe solution stopsincreasing.
Freezing Point DepressionandBoiling Point ElevationBoiling Point Elevation• ∆Tb=mkb(for water kb=0.51oC/m)•Freezing Point Depression• ∆Tf=mkf(for water kf=1.86oC/m)•Note:m is the molality of the particles,so if the solute is ionic, multiply by the #ofparticles it dissociates to.
Which is more effective for loweringthe freezing point of water?• NaClorCaCl2
Example 1:•Find the new freezing point of 3m NaCl inwater.
Example 2:•Find the new boiling point of 3m NaCl inwater.