1. Properties of Solutions
Part I
Chapter 17

2. Solute & Solvent The SOLUTE is dissolved in the SOLVENT. SOLVENT
Solvents & solutes can be gases, liquids, or solids.

3. Like Dissolves Like Polar H2O Polar NaCl Polar H2O Nonpolar oil
salt water
Oil/water
Polar H2O
Polar NaCl
Polar H2O
Nonpolar oil

4. Three Ways to Increase the Rate of Dissolution:
Agitation: stirring / mixing breaks up ionic compounds quickly
Dissolves faster
(not more)
Dissolves more slowly
(same amount)

5. Three Ways to Increase the Rate of Dissolution:
2. Temperature: heat makes compounds dissolve faster (more kinetic energy)
Hot tea:
sugar
dissolves
quickly
Iced tea:
sugar
dissolves
slowly

6. Three Ways to Increase the Rate of Dissolution:
Particle size: smaller compounds dissolve faster (more surface area)
Ex.:
Artificial sweetener:
Fine powder, dissolves quickly
Brown granulated sugar:
Large crystals, dissolves slowly

7. Solubility
Increasing the temperature ALSO increases the maximum amount of solid solute that can dissolve in a given amount of solvent (SOLUBILITY).

8. Solubility of Salts
temp
amount
dissolved
One exception

9. Describing Solution Composition
salt water
Unsaturated: contains less than the maximum
Saturated: contains the maximum amount of solute at a specific temperature.
Supersaturated: contains more than the maximum
salt water
(special conditions)

10. How do you make a Supersaturated Solution?
Heat the solution so a BUNCH of solute dissolves.
Then cool it slowly…be very careful!

11. Then add a “Seed Crystal”

12. Look Out! The system has been disturbed!

13. Solubility of Gases in H2O
Gas molecules escape
Increase
temp
Gas molecules are dissolved

14. Henry’s Law
Henry’s Law: solubility of a gas is directly proportional to pressure above the liquid
Low solubility
High solubility

15. Solubility of Liquids Miscible: liquids that dissolve in one another
Immiscible: liquids that are insoluble in one another (opposite polarities)

16. CHROMATOGRAPHY EXAMPLE-SETUP
Green
Use 25mL water.
Write with pencil ONLY.
Make a TINY dot.
Don’t let papers touch each
other.
Don’t let papers touch side.
Crease in middle – point inward.
1.5 cm

17. Solutions Part II

18. Solution Concentration
Describes the amount of solute dissolved
moles of solute
Molarity =
liters of solution
If molarity is small, the solution is dilute
If molarity is large, the solution is concentrated.

19. Making Dilutions
Calculates amount of water to add to reduce the concentration
M1V1 = M2V2
M = molarity
V = volume
Stock
(concentrated)
New Solution:
Stock + Water

20. Colligative Properties
Solutions have several properties that are different from pure liquids
The effect depends on concentration

21. Lower Vapor Pressure
Because there are fewer solvent molecules at the surface
Higher pressure Lower pressure

22. Boiling Point Elevation
More heat must be added because of the lower vapor pressure
Lower Higher

23. Freezing Point Depression
The solute interferes with the orderly pattern of the solid, requiring more kinetic energy to be removed

24. CHROMATOGRAPHY EXAMPLE-ANALYSIS
Green
Mark solvent front (water stops).
Write with pencil ONLY.
Measure Df.
Measure Ds for each color (1or2).
Don’t let papers touch side.
Crease in middle – point inward.
Ds-
blue Df
Ds-
yellow