Chemistry GIA 8-1
Unit: Solutions and Solubility Reading: Chapter 16
Working
Mode: Pairs. Solve the problems on a separate sheet of notebook paper. Each
student must submit their own work on their own sheet of paper.
Learning
Objective: Determine molarity of a solution and components of a solution based
on various pieces of information.
Problem 1: You are working with an HCl acidic solution in which 23.4 g of gaseous HCl was dissolved to make a 500. mL solution.
Step 1: Determine the moles of HCl used.
Step 2: Determine the molarity of the solution.
Problem
2:You have made an aqueous
solution of sodium phosphate (Na3PO4: MM = 163.9 g) using
3.27 g of solute and making an aqueous solution with a volume of 250. mL.
Determine the concentration of your solution according to the following
steps.
Step 1: Determine the moles of Na3PO4 used.
Step 2: Determine the molarity of the solution.
Problem
3: Oxygen gas is slightly soluble in water.
At 20oC [O2] = 1.38 x 10-3 M.
How many grams of O2 are dissolved in the water of an 80.0 L
fish tank?
Problem
4: NaCl has a solubility of
35.7 g NaCl per 100.g of H2O at 0oC.
If the resulting solution has a density of 1.12 g/mL, what would be the
concentration in molarity of a saturated NaCl solution?
Step 1: Determine the total mass of the solution.
Step 2: Determine the volume of the solution in liters.
Step 3: Determine moles of solute present.
Step 4: Determine [NaCl].
Problem 5: An aqueous solution of sodium phosphate (Na3PO4: MM = 163.9 g) has a density of 1.15 g/mL and contains 22.0% by mass (mass of solute/mass of solution) of sodium phosphate. Determine the number of moles of sodium ions (Na+) in one liter of the solution. Don’t forget each sodium phosphate formula unit contains three sodium ions.
