Solution Composition: Molarity

I. VIDEO ON MOLARITY

A. Part One

B. Part Two

II. NOTES ON MOLARITY

Molarity describes the amount of solute in moles and the volume of solution in liters. Molarity is the number of moles of solute per volume of solution in liters.

M= molarity = moles of solute = mol

liters of solution L

III. EXERCISES ON MOLARITY

1. Calculate the molarity of a solution prepared by dissolving 11.5 g of solid NaOH in enough water to make

1.50 L of solution.

2. Calculate the molarity of a solution prepared by dissolving 1.56 g of gaseous HCl into enough water to

make 26.8 mL of solution.

3. Calculate the molarity of a solution prepared by dissolving 1.00g of ethanol, C2H5OH, in enough water to

give a final volume of 101 mL.

4. Give the concentrations of all the ions in each of the following solutions:

a) 0.50 M Co(NO₃)₂ b) 1 M FeCl₃

5. Give the concentrations of the ions in each of the following solutions:

a) 0.10 M Na₂CO₃ b) 0.010 M Al₂(SO₄)₃

6. How many moles of Ag⁺ ions are present in 25 mL of a 0.75 M AgNO₃ solution?

7. Calculate the number of moles of Cl^- ions in 1.75 L of 1.0 x 10^-3 M AlCl₃

8. To analyze the alcohol content of a certain wine, a chemist needs 1.00 L of an aqueous 0.200 M K₂Cr₂O₇ solution. How much solid K₂Cr₂O₇ (molar mass = 294.2 g) must be weighed out to make this solution?

9. Formalin is an aqueous solution of formaldehyde, HCHO, used as a preservative for biological specimens.

How many grams of formaldehyde must be used to prepare 2.5 L of 12.3 M formalin?

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