1. Unit 12. Solutions (including Molarity)

2. Solutions and Solubility

3. SOLUTION
A homogeneous mixture
All parts are uniformly mixed

4. Terms
Solvent – the substance present in the largest amount in a solution.
The substance that does the dissolving.
Solute – the other substance or substances in a solution.
The substance that is dissolved.

5. Terms Saturated Unsaturated
When a solution contains the maximum amount of solute
Unsaturated
When a solvent can dissolve more solute

6. Few more terms… Concentrated Dilute
When a relatively large amount of solute is dissolved
Dilute
When a relatively small amount of solute is dissolved

7. Factors Affecting the Rate of Dissolution
Surface Area
Stirring
Temperature

8. But solid can reform…
Crystallize - solid comes out of solution

9. Temperature vs Solubility Let’s practice reading this…

10. Using the graph to do some math…
How much KNO3 will dissolve at 60oC in 100 grams of water?
How much will dissolve in 50 grams water?
What chemical will dissolve 60g in 100g of water at 24oC?
How many grams of KCl will come out of a 90oC solution if it is cooled to 30oC?

11. Molarity (or M)

12. We need to review Moles first…
How do we convert between grams and moles?

13. MOLARITY Molarity-the number of moles of solute per liters of solution
Ie. Concentrated HCl is 12M solution
M = molarity = moles of solute
liter of solution

14. Moles over liters Try and remember it this way.

15. The Molarity Triangle
mol M L

16. So why is molarity so important?
We need to be able to make solutions and dilutions…

17. SOLUTIONS Add a certain amount of solute to a set amount of solvent
Sample:
1. How much KNO3 do I add to make 300mL of a 2.1M solution?
2. What is the molarity of NaOH I can made if I add .85 moles to 1L?

18. DILUTIONS
M1 x V1 = M2 x V2
Where M = molarity
V = volume

19. Dilutions Sample
What volume of 16 M sulfuric acid must be used to prepare 1.5 L of a 0.10 M H2SO4
What volume of 12 M HCl must be used to prepare 0.75 L of a 0.25 M HCl?