Module 4 Intro

1. Module 4 Intro

1.39. Page 5

Lesson 5

Module 4—Properties of Solutions

Read

Ion Concentrations

A diagram depicts the dissociation of magnesium chloride. On the left of the arrow one purple sphere labelled Mg 2 plus is joined to two green spheres each labeled Cl minus. On the right side of the arrow the purple sphere is shown alone separated by the plus sign and the two separated green spheres.

Recall from previous lessons that many substances dissociate in water to form ions. It is possible to calculate the concentration of these ions using amount concentrations and a balanced chemical formula. Read “Concentration of Ions” on pages 210 and 211 in your textbook for more information on the effect dissociation has on the ion concentration in a solution. Then work through “COMMUNICATION examples” 12, 13, and 14 on pages 211 and 212.

Self-Check

SC 8. Determine the amount concentration of calcium ions and acetate ions in a 0.81-mol/L solution of calcium acetate.

SC 9. Determine the amount concentration of the sodium ions and carbonate ions in a 0.65-mol/L solution of sodium carbonate.

SC 10. Determine the amount concentration of the ammonium ions and the phosphate ions in a 1.15-mol/L solution of ammonium phosphate.

SC 11. Determine the amount concentration of potassium ions and dichromate ions in a solution made by dissolving 42.5 g of potassium dichromate to make a volume of 160 mL.

SC 12. What mass of aluminium chloride must be dissolved to make 52 L of solution with a chloride-ion concentration of 0.45 mol/L?