1. Today: Quiz next time we meet! HW – Read pages 257-258
Worksheet – Concentrations of solutions
Worksheet - Molarity Problems 1

2. Molarity Problems 1 0.0066 mol Na+ ions 0.120 M KMnO4
5.61 g (6 grams KMnO4)
139 mL CaCl2
0.44 g NaCl
a) 207 g Ca3(PO4)2
b) Na3PO4
c) M %

3. Limiting Reagents Involving Molarity
Calculate moles of each reactant
Solve like a usual LR problem

4. Limiting Reagents involving Molarity
What mass of AgCl can be obtained by mixing 1.00L of 0.55 M BaCl2 with 2.00 L of 1.2 M AgNO3?

5. Diluting a Stock Solution
To make a solution LESS Concentrated:
Add solvent
Number of moles of solute does not change
Use formula: M1V1 = M2V2

6. Molarity
Molarity = concentration term used to describe an amount of solute dissolved in a given amount of solvent.
Stock solution = concentrated solution. This contains large quantities of solute dissolved in solvent
Dilute solution = contains small amounts of solute dissolved in solvent

7. Molarity
Take 2.00 grams of CuSO4 and dissolve it into 100. mL of water.
Calculate the molarity (M) of the stock solution.
0.125 M CuSO4 = stock solution
How was the stock solution prepared?

8. Preparation of Stock Solution
Weigh out 2.00 grams of copper(II) sulfate
Fill a 100. mL volumetric flask approximately ½ way with water.
Add in the solute (2.00 g)
Agitate until solute is completely dissolved.
Add water (solvent) until the solution reaches the line (score mark).

9. Preparation of diluted solution
Take 3.00 mL of the stock solution and add it to a 25 mL volumetric flask; dilute to the line.
What is the molarity (M) of the diluted solution?
Use this formula: M1V1 = M2V2

10. Dilution M1 = 0.125 M V1 = 3 mL M2 = ? V2 = 25 mL M2 = 0.0150 M
How was the dilution prepared?

11. Preparation of diluted solution
Take 3.00 mL of the stock solution using a volumetric pipette.
Add to a 25 mL volumetric flask.
Dilute with water until the solution reaches the line.
Mix the solution.

12. Molarity and Dilution 0.031 M 5 Liters 0.76 L 4.24 L evaporated
grams
By Monday – fish will die – you must come in! ( M)
5. a. Bert
b M = Hank; M = Bert
c. 28 mL

13. Molarity
M1V1 = M2V2
Prepare 25 mL of 0.35M solution NaHCO3 from a stock solution which is 0.97M. How would you prepare the solution?

14. Molarity and Dilution Problems
94 moles
5.5 L pure alcohol
Problem 7
0.137 M
Problem 8
Weigh out 2205 grams of K2Cr2O7. Add it to a 5L volumetric flask that is ½ filled with water. Agitate to dissolve. Fill to the line with water.
Take 30. mL of stock solution using a volumetric pipette. Add it to a 450mL volumetric flask. Fill to the line with water. Shake.

15. Molarity and Dilution Problems
1.2 x 10-6 M
2.08 x 10-6 grams