Question

You have two 401.0 mL aqueous solutions. Solution A is a solution of silver nitrate, and solution B is a solution of potassium chromate. The masses of the solutes in each of the solutions are the same. When the solutions are added together, a blood-red precipitate forms. After the reaction has gone to completion, you dry the solid and find that it has a mass of 331.8 g. (a) Calculate the concentration of the potassium ions in the original potassium chromate solution. (b) Calculate the concentration of the chromate ions in the final solution.

Answer 1

- Given the mass of solute and volume of solvent, calculate the concentration of a solution.

- Given the concentration of a solution, determine the amount of solute in a given amount of solution.

- Given the concentration of a solution, determine the amount of solution that contains a given amount of solute.

The concentration of a solution is a measure of the amount of solute in a given amount of solvent or solution. Some medications are solutions of drugs--a one-teaspoon dose at the correct concentration might cure the patient, while the same dose in the wrong concentration might kill the patient.

In this section, we introduce two different ways of expressing the concentrations of solutions: molarity and molality.

Sometimes solutions are referred to as "dilute" or "concentrated," but these are not very definite terms. "Dilute" just means that there is a relatively small amount of solute in a solvent. "Concentrated," on the other hand, means that there is a relatively large amount of solute in a solvent. Note that these terms are unrelated to the degree to which a solution is saturated. A saturated solution of a substance that is not very soluble might be very dilute.