1. Molarity (M) Expresses solution concentration M = moles of solute / liters of solvent Molarity, molar, M, and mol/liter all represent the same ratio Episode 1003

2. Ex #1 A saline solution contains 0.90 g per 95 mL of solution. What is the molarity? M = moles of solute / liters of solution 0.90 g NaCl 58.5 g NaCl 1 mol NaCl = 0.015 mol NaCl 95 mL1 Liter 1000 mL = 0.0950 L 0.015 mol NaCl 0.0950 L 0.16 M Episode 1003

3. Ex #2 How many moles of solute are contained in 2.5 L of 0.30 M CaCl 2 ? M = moles of solute / liters of solution 0.30 M = 0.30 moles/1 liter 2.5 L0.30 mol 1 L = 0.75 mol If grams are involved, convert to grams to moles or moles to grams. Episode 1003

4. Colligative Properties Any of the properties of a solution that change when the concentration of the solution changes. Depend on the number of particles dissolved in a given mass of solvent Episode 1003

5. Examples of Colligative Properties Vapor Pressure Depression – The lowering of the vapor pressure of a liquid that occurs when a substances are dissolved in the liquid Vapor pressure: – The pressure of a vapor in equilibrium with its liquid Episode 1003

6. Freezing Point Depression – The lowering of the freezing point of a liquid that occurs when substances are dissolved in the liquid (Ex. Using antifreeze in car radiators and salt on icy roads) Boiling Point Elevation – The raising of the boiling point of a liquid that occurs when substances are dissolved in the liquid (Ex. Antifreeze in a car acts as a coolant in the summer.) Episode 1003