1. Colligative Properties
Physical properties (melting point and boiling point) of solutions depend on the concentration of solute particles in solution

2. Freezing point depression
When a solute is dissolved in a liquid the freezing point of the solution will be lower ↓ than the pure liquid.
The freezing point of water is less than 0oC if something is dissolved in it.

3. Boiling point Elevation
When a solute is dissolved in a liquid the boiling point of the solution will be higher ↑ than the pure liquid.
The boiling point of water is more than 100oC if something is dissolved in it.

4. 1m electrolyte vs. 1m non-electrolyte
How much ΔT changes depends on
Concentration of SOLUTE PARTICLES in sol’n
1m electrolyte vs. 1m non-electrolyte
1m NaCl vs. 2m NaCl
1m NaCl vs. 2m C12H22O11

5. Which would result in the lowest freezing point / highest boiling point?
1m NaCl (aq)
1m C12H22O11(aq)
1m C2H6O2(aq)
1m CaCl2(aq)

6. answer 1m NaCl (aq) only 2 particles ionize
1m C12H22O11(aq) non-electrolyte
1m C2H6O2(aq) non-electrolyte
1m CaCl2(aq) b/c this will ionize into the greatest number (3) of particles
CaCl2 Ca2+ + 2Cl-

7. Which would result in the lowest freezing point / highest boiling point?
2m NaCl (aq)
1m C12H22O11(aq)
1.5m C2H6O2(aq)
1m CaCl2(aq)

8. answer
2m NaCl (aq) BECAUSE 2m NaCl (aq) ionizes into 2 particles x 2m = 4m concentration of particles in solution
1m C12H22O11(aq) doesn’t ionize (non-electrolyte) = 1m concentration of particles in solution
1.5m C2H6O2(aq) doesn’t ionize = 1.5m concentration of particles in solution
1m CaCl2(aq) ionizes (electrolyte) into 3 particles, but only 1m concentration = 3m concentration of particles in solution

9. Different solvents have different Kf & Kb
∆Tb = Kb m
∆Tf = Kf m
We could calculate the actual freezing point and boiling point, but we’ll save that for another time.

10. THE END