1. Types of Solutions and Solubility Curves Mrs. Wilson
Monday 4-18 and Tues 4-19
Types of Solutions and Solubility Curves
Mrs. Wilson

2. Objectives
Distinguish between solutions, colloids, and suspensions; electrolytes and non-electrolytes; and strong / weak electrolytes.
Distinguish between solutions based on their degree of saturation: saturated, supersaturated, and unsaturated solutions.
Interpret solubility curves for different ionic compounds to determine the degree of saturation of a solution.
Homework: Colors of Chemistry Lab due next class. We’ll finish the lab questions next class.

3. Daily Quiz
You do not need a calculator. You do need a periodic table.

4. Lesson 6.5: Types of Solutions A. Solutions, Colloids, Suspensions

5. Lesson 6.5: Types of Solutions A. Solutions, Colloids, Suspensions
Tyndall effect: shown only in colloids – the colloidal particles are larger than the wavelength of the incident light, so that light beam “scatters” or broadens in width. Think of car headlights shining through fog.

6. Dissociation = separation of ions from each other
Lesson 6.5: Types of Solutions B. Electrolytes vs. Nonelectrolytes; Weak vs. Strong Electrolytes
Dissociation = separation of ions from each other
All three solutions have complete dissolution (solute is completely dissolved)
~100% dissociation
0% dissociation
Ex: Sugar water
Ex: Vinegar, ammonia
Ex: HCl, salt water

7. DEMO and VIDEO Water, Gatorade, Monster
Any of you have drinks you want to test?  (You can’t drink them afterwards, obviously…)

8. Lesson 6. 5: Types of Solutions C
Lesson 6.5: Types of Solutions C. Saturated, Unsaturated and Supersaturated Solutions
Unsaturated = contains less than the max. mass of solute that could possibly dissolve in 100 g of H2O at a given temperature.
Saturated = contains the max. mass of solute that can dissolve in 100 g H2O at a given temp.
**As long as that temp. remains constant, any extra solid solute will be undissolved at the bottom of the saturated solution.
** The only factor that can change the solubility of a solute is temperature and pressure (for gaseous solutes only). To make
a saturated solution, unsaturated, heat the solution!

9. VIDEO
Unsaturated, Saturated and Supersaturated Project

10. Lesson 6. 5: Types of Solutions C
Lesson 6.5: Types of Solutions C. Saturated, Unsaturated and Supersaturated Solutions
Supersaturated = contains more than the max. mass of solute that solution can normally dissolve
Make a saturated solution (w/ undissolved solute at the bottom)
Heat the mixture to dissolve the solute (now it’s unsaturated)
Cool the mixture EXTREMELY SLOWLY. Now it’s supersaturated.
This system is unstable – any disturbance or the addition of a “seed crystal” will trigger crystallization to re-form a saturated solution.

11. QUICK LAB and VIDEO There are three setups.
Crystallization
There are three setups.
Perform a test to see if the two test tubes contain an unsaturated, saturated or supersaturated solution.
Obtain a test tube that contains a warmed solution. Perform a test to see if this test tube contains an unsaturated, saturated or supersaturated solution. Return this test tube to the hot water bath.

12. Lesson 6. 5: Types of Solutions C
Lesson 6.5: Types of Solutions C. Saturated, Unsaturated and Supersaturated Solutions
Another way to distinguish degrees of saturation is to consult a solubility curve.
Supersaturated
Unsaturated

13. Any point on a line represents a saturated solution.
Example
At 90oC, 40 g of NaCl(s) in 100g H2O(l) represent a saturated solution.
Any point below a line represents an unsaturated solution.
Example
At 90oC, 30 g of NaCl(s) in 100g H2O(l) represent an unsaturated solution. 10 g of NaCl(s) has to be added to make the solution saturated.

14. Any point above a line represents a supersaturated solution. Example
At 90oC, 50 g of NaCl(s) in 100g H2O(l) represent a supersaturated solution. Eventually, 10 g of NaCl(s) will crystallize; the liquid above the crystals will be saturated.
Any solution can be made saturated, unsaturated, or supersaturated by changing the temperature.
For solid solutes, when T increases, solubility increases.
For gaseous solutes, when T decreases, solubility increases.

16. (answers to these questions and the homework is online)

17. Let’s go over the test…