1. Colligative Properties

2. Properties where how much solute dissolved matters not what is being dissolved. Ex: Osmosis

3. Colligative Properties Boiling Point Elevation Ex: coolant/ethylene glycol – Lowers the boiling point of water Boiling point elevation ∆T = k b m

4. Colligative Properties Boiling point elevation ∆T = k b m What is the boiling point of 50. g of ethylene glycol in 50. g of water?

5. Colligative Properties Freezing Point Depression Ex: salt on ice – This melts ice by lowering the freezing point of the water Ex: Antifreeze/ethylene glycol Freezing point depression ∆T = k f m

6. Colligative Properties Freezing point depression ∆T = k f m What is the freezing point of 25 g of glucose, C 6 H 12 O 6, in 75 g of ethanol?

7. Colligative Properties This works well for nonelectrolytes This a problem for electrolytes Electrolytes (ionic compounds and acids) break into ions in water. Remember the definition of a colligative property – It doesn’t matter what is dissolved just how much

8. Colligative Properties NaCl  Na + + Cl - 1 m of NaCl is really 1 m of Na + and 1 m Cl - giving a total of 2 m K 3 PO 4  3K + + PO 4 -3.25 m of K 3 PO 4 is really.75 m of K + and.25 PO 4 -3 giving a total of 1.0 m

9. Colligative Properties For the following solutions what is the total concentration. 0.15 m CuCl 2 2.5 m CH 3 0.50 m H 2 CO 3 0.20 m Al 2 (SiO 3 ) 3

10. Colligative Properties Which of the following would have the highest boiling point? 0.25 m KCN 1.0 m CH 3 OH 0.50 m Ca(NO 3 ) 2 0.40 m HCl

11. Colligative Properties What is the boiling point of 5.0 g of CuSO 4 in 20. g of water?