1. Solution Concentration
Molarity

2. Dilute vs. Concentrated
Qualitative descriptions of a solution
Weak solution
few particles of solute in a solvent
Strong Solution
LOTS of solute particles dissolved in a solvent

3. Which is more concentrated?
5 mol in 1 L of solution or 1 mol in 5L of solution
2.5 mol in 2 L solution or 3.0 mol in 1.5L solution
Which picture?

4. (M)olarity is the Quantitative measure of solution concentration
number of moles of solute dissolved per liter of solution

5. What is the Molarity (M) of a solution if 37
What is the Molarity (M) of a solution if 37.0g of KCl is dissolved to make mL of solution?
Step 1 CONVERT
250.0mL .250L
37.0g of KCl to moles

6. Step 2 SUBSTITUTE into Formula

7. If you add water or evaporate it you will change the molarity of the solution
Use this formula to determine the new molarity…
M1V1 = M2V2

8. If a 5.0L solution is 2.0M and 1500.0 mL of water is added, what is the new (M)olarity?
Step 1 MAKE a list and do any conversions
M1 = 2.0
V1 = 5.0L
M2=?
V2= 1500mL 1.5L+ 5.0L = 6.5L
In this problem….You have to add
for the total solution volume

9. M1V1 = M2V2 (2.0M) (5.0L) = M2 (6.5L) 1.54M = new molarity
STEP 2 SUBSTITUE and solve
M1V1 = M2V2
(2.0M) (5.0L) = M2 (6.5L)
1.54M = new molarity

10. IF you want to make 500mL of a 1. 5M solution from a 12
IF you want to make 500mL of a 1.5M solution from a 12.0M solution, How much of the concentrated solution do you need and how much water do you need?
M1 = 1.5M
V1 = 500mL
M2=12M
V2= ?
M1V1 = M2V2
(1.5)(500) = (12)V2
V2 = 62.5mL
Ask yourself…..what does this volume represent????

11. This represents the volume of the concentrated solution (12M) you need.
But I need 1.5M and 500mL of it….how do I get there?
To go from 12M to 1.5M you have to add water.
But how much water????
Let’s draw a diagram to find out.

12. 62.5mL of 12M 500mL of 1.5M TOTAL Vol you WANT Vol you have
500mL – 62.5mL = 437.5mL
Vol you need to ADD

13. Molarity Practice
M1V1 = M2V2

14. THE END