1. Concentration of Sol’n16-2 The amount of solute in a given amount of solvent or solution

2. THE MOLE The mole is used to express the concentration of a solution. The mole is used to express the concentration of a solution. Concentrated sol’n contain large amounts of solute and small amnt of solvent Concentrated sol’n contain large amounts of solute and small amnt of solvent Dilute sol’n contain small amnts of solute and large amnts of solvent. Dilute sol’n contain small amnts of solute and large amnts of solvent.

3. Molarity If defined in terms of volume of soln, depends on T. If defined in terms of volume of soln, depends on T. Molarity = moles of solute Molarity = moles of solute liters of solution mol M = mol L

4. Example #1 If a manufacturer prepares a soln from 10.0g of NaOH dissolved in enough solvent to make.10L of soln. What is the M of the cleaner? If a manufacturer prepares a soln from 10.0g of NaOH dissolved in enough solvent to make.10L of soln. What is the M of the cleaner? 10gNaOH x 1mol NaOH = 2.5 mol/L 10gNaOH x 1mol NaOH = 2.5 mol/L.10L 40g NaOH.10L 40g NaOH 2.5M 2.5M

5. Mole Fraction See Practice Worksheet #1 See Practice Worksheet #1

6. Making Dilutions Diluting a solution reduces the number of moles of solute per unit volume, but it does not change the total number of moles of solute. Diluting a solution reduces the number of moles of solute per unit volume, but it does not change the total number of moles of solute. Moles of solute B4 dl = mols of solute after dl Moles of solute B4 dl = mols of solute after dl M 1 V 1 = M 2 V 2 M 1 V 1 = M 2 V 2

7. Example #3 How many mL of aqueous 2.0M MgSO 4 solution must be diluted with water to prepare 100mL of aq. 0.40 M MgSO 4 ? How many mL of aqueous 2.0M MgSO 4 solution must be diluted with water to prepare 100mL of aq. 0.40 M MgSO 4 ? M 1 = 2.0M M 1 = 2.0M M 2=.40M M 2=.40M V 1 = ??? V 1 = ??? V 2 = 100mL V 2 = 100mL

8. Percent Solutions Conc. of solution in % expresses the ration of the volume of solute to the volume of solution. Conc. of solution in % expresses the ration of the volume of solute to the volume of solution. When both the solute and the solvent are liquids When both the solute and the solvent are liquids Ex. 91% alcohol contains 91 mL of isopropyl alcohol (2-propanol) with enough water to make 100 mL of solution Ex. 91% alcohol contains 91 mL of isopropyl alcohol (2-propanol) with enough water to make 100 mL of solution %by Volume = volume of solute x 100 %by Volume = volume of solute x 100 volume of soln volume of soln

9. Example #4 What is the percent volume of ethanol in the final solution when 85 mL of ethanol is diluted to a volume of 250mL with water? What is the percent volume of ethanol in the final solution when 85 mL of ethanol is diluted to a volume of 250mL with water? A bottle of hydrogen peroxide is labeled 3%. How many mL of H 2 O 2 are in a 400mL bottle of this solution? A bottle of hydrogen peroxide is labeled 3%. How many mL of H 2 O 2 are in a 400mL bottle of this solution?