1. Osmotic Pressure

2. Separated Solutions
Semipermeable membrane- separates a sol’n and pure solvent, but only allows pure solvent to pass through

3. Osmosis
The vol of the sol’n will increase and the solvent will decrease
The flow of solvent is osmosis

6. Equilibrium Liquid levels eventually stop changing to equilibrium
There will be greater pressure on the sol’n b/c the liquid levels are different

8. Osmotic Pressure
The extra pressure on the solution is the osmotic pressure
Or the minimum pressure that stops osmosis = the osmotic pressure

9. Colligative Property?
You bet! More solute, more osmotic pressure

10.  = MRT  = osmotic press in atms M = molarity R = gas law const
T = temp in Kelvin

11. A problem
The osmotic pressure of a sol’n containing 26.5 mg of aspartame per L is 1.70 torr at 30oC. Calculate the molar mass of aspartame

12. Electrolyte sol’ns
Remember how we talked about electrolytes contribute the number of ions that they dissociate into???

13. van’t Hoff factor i
Not every single molecule dissociates, so i is the value for the actual dissociation
It will be given to you

15. Easy changes
Our eqns are now:
T = imK (freezing or boiling)
 = iMRT

16. Homework
P 545
67, 69, 77