1. Warm-up February Tuesday
Please get out your notes and lab paper. Read the lab Background section for part II and write down two questions you have about the lab.

2. Bellwork February Wednesday : Smarties!
Table 1: Just put smartie in your mouth
Table 2: Swirl smartie, but don’t chew
Table 3: Chew smartie, then let dissolve
Questions
What are three things that can speed up the dissolution of the smartie?
Will temperature always affect how substances dissolve? Why or why not?

3. Chemistry I Chapter 16 - Solution Formation

4. 16.1 properties of solutions Factors affecting rate of solution:
Agitation
brings fresh solvent in contact w/ solute
does not affect amount the amount of substance that dissolves

5. Factors affecting rate of solution:
Temperature
heat increases rate of solution by increasing kinetic energy and motion of particles

6. Factors affecting rate of solution:
Particle size
smaller particles dissolve faster because of greater surface area

7. Question What would dissolve faster? A cube of sugar Granulated sugar
Powdered sugar
Why?

8. Solubility - a measure of the amount of solute that will dissolve in a given amount of solvent.
we usually use g solute/100 g solvent
0ºC
20ºC
100ºC
Ba(OH)2
1.67
31.89
------
NaCl
35.7
36.0
39.2
Sucrose
179
230.9
487

9. Factors affecting solubility:
The nature of the solute and the solvent
“like dissolves like”

10. Factors affecting solubility:
Temperature
Most solids become more soluble at a higher temperature. A few become less soluble.

11. Factors affecting solubility:
solubility of gases decreases as temperature increases

12. Factors affecting solubility:
Pressure (for solutions of gases in liquids)
increasing pressure increases solubility of gas

13. Question
Pressurized CO2 is pumped into three cans of soda. The first can is at 10ºC, the second is at 20ºC and the third is at 50ºC. In which can will the most gas dissolve and why?

14. Saturated solution -contains the maximum amount of solute that will dissolve in a given amount of solvent at a given temperature.
Unsaturated solution- more solute could be dissolved
-indicated by no solid present
Supersaturated solution- more solute is dissolved than is theoretically possible at a given temperature.

16. EXAMPLE:
How could you determine if a solution is saturated, unsaturated or supersaturated?
If solid is present – it is Saturated
If no solid is present – it is unsaturated or supersaturated
To determine which, add a crystal
Supersaturated will crystallize
Unsaturated will dissolve the crystal
DEMO

18. Cloud seeding is a practical example of supersaturation.

19. Interpreting a solubility graph
What is the solubility of KNO3 at 60oC?
Is a solution of KNO3 with a concentration of
90g/100g H2O at 70oC be saturated,
unsaturated or supersaturated?
How many g of KNO3 can be dissolved in
200g of H2O at 30oC?

20. Miscible - liquids that are soluble in each other
Ex. ethanol and water
Immiscible- liquids that are not soluble in each other
Ex. oil and water

21. Question Which of the following would be miscible in a polar solvent?
HCl
NaOH
Gasoline
MgBr2
Sugar
Olive oil
LiCl

22. Henry’s Law- At a given temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid.
S = S2
P P2

23. EXAMPLE:
At 25oC, the solubility of a certain gas in H2O is 0.75 g/L of H2O at a pressure of 1.0 atm. What is the solubility of the same gas at 10.0 atm pressure?
S1 = 0.75 g/L
P1 = 1.0 atm
S2 = ?
P2 = 10.0 atm
S S2
P P2 = x
x = g/L =