Solutions Worksheet
Objectives:
• Define solution concentrations
• Calculate solution concentrations
• Calculate solute contained in solution volumes
• Perform dilution calculations
1. Define the solution concentrations:
% by mass
Molarity
2. Calculate the solution concentrations
• What is the % by mass of this solution: 25.0g MgCl2 is added to 125.0g of water.
• 0.126 moles of a substance is added to 205.0 ml. What is the molarity of the solution?
• 57.65 g MgCl2 is added to water to make a solution with the final volume of 250.0 mL.
What is the molarity of this solution?
• 25.0 ml Alcohol is dissolved in sufficient water to give a total volume of 250.0 mL.
What is the percent by volume concentration of the alcohol?
3. Solve the problems
• How many grams of solute are in a 75.0ml aliquot of a 10.0% NH4Cl solution?
• How many grams of solute are in a 75.0ml aliquot of a 1.25M NH4Cl solution?
4. Dilution calculations
• 175.0 ml of a 2.00M NaCl stock solution and dilute it to a final volume of 1.00 L. What
is the molarity of the final solution?
• How would you make 200.0 ml of a 0.250M solution from a 3.25 M concentrated stock
solution?
•
% = mass solute * 100
mass solution
Answers
1.
2.
3.
4.
•
M = Moles solute / Liters
solution
Calculations
•
16.7 %
•
0.615M
•
2.42 M
•
10.0%
Problems
•
7.5 g
•
5.01 g
Dilution
•
0.350 M
•
15.4 ml
Take 15.4 ml of stock and dilute it
up to 200.0 ml with water
©2009 Dr S. Buktenica