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Factors that Determine Rate of Dissolving How can you make something dissolve faster or slower? How can you make something dissolve faster or slower? Nature of solvent and solute Nature of solvent and solute Stirring Stirring Temperature Temperature Surface Area Surface Area

Calculating Solubility Saturated solution Saturated solution Maximum amount of solute for a given amount of solvent at constant temperature Maximum amount of solute for a given amount of solvent at constant temperature Unsaturated solution Unsaturated solution Solution that contains less solute than a saturated solution Solution that contains less solute than a saturated solution Supersaturated solution Supersaturated solution Solution that contains more solute than it can hold at a given temperature Solution that contains more solute than it can hold at a given temperature Solubility Solubility Amount that dissolves in a given quantity of a solvent at a given temp Amount that dissolves in a given quantity of a solvent at a given temp Miscible vs. Immiscible Miscible vs. Immiscible

Affecting Solubility of Solutions and of Gas in Liquid Temperature effects Temperature effects Increase temperature, increase solubility Increase temperature, increase solubility Gas/Liquid – increase temp, decrease solubility Gas/Liquid – increase temp, decrease solubility Pressure effects Pressure effects Only for gases: increase pressure, increase solubility Only for gases: increase pressure, increase solubility Henry’s law Henry’s law Solubility of gas proportional to pressure of gas above liquid Solubility of gas proportional to pressure of gas above liquid Practice 1-2 Practice 1-2

Calculating Molarity of Solution Concentration Concentration Measure of amount of solute dissolved in solvent Measure of amount of solute dissolved in solvent Dilute vs. Concentrated Dilute vs. Concentrated Molarity Molarity Number of moles of solute dissolved per liter of solution Number of moles of solute dissolved per liter of solution Moles = M x V Moles = M x V M = moles/volume M = moles/volume Practice 8-11 Practice 8-11

Calculating Dilutions Moles of solute before dilution = moles of solute after dilution Moles of solute before dilution = moles of solute after dilution M1 x V1 = M2 x V2 M1 x V1 = M2 x V2 Practice Practice 12-13

Determining percent by volume and percent by mass Percent by volume (%(v/v)) = volume of solute/solution volume x 100% Percent by volume (%(v/v)) = volume of solute/solution volume x 100% Percent (mass/volume) = mass of solute/solution volume x 100% Percent (mass/volume) = mass of solute/solution volume x 100% Practice Practice 14-17

Colligative Properties Depend only on number of particles dissolved in given mass of solvent Depend only on number of particles dissolved in given mass of solvent Volatile vs. Nonvolatile solvents Volatile vs. Nonvolatile solvents Solution with nonvolatile solute – lower VP than pure solvent Solution with nonvolatile solute – lower VP than pure solvent Proportional to number of particles the solute makes in solution (NaCl vs. glucose) Proportional to number of particles the solute makes in solution (NaCl vs. glucose) Boiling Point Elevation Boiling Point Elevation Increase in BP due to solute Increase in BP due to solute Freezing Point Depression Freezing Point Depression Decrease in FP due to solute Decrease in FP due to solute

Calculating Molality and Mole Fraction Molality – number of moles of solute dissolved per kilogram of solvent Molality – number of moles of solute dissolved per kilogram of solvent Used in Colligative properties problems Used in Colligative properties problems Practice Practice Mole Fraction Mole Fraction Ratio of moles of solute to total number of moles of solvent and solute Ratio of moles of solute to total number of moles of solvent and solute Practice Practice 30-31

BP Elevation and FP Depression Change in temp = Kb x molality Change in temp = Kb x molality Kb = molal boiling point elevation constant Kb = molal boiling point elevation constant Practice Practice FP Depression FP Depression Change in temp = Kf x molality Change in temp = Kf x molality Kf – molal freezing point depression constant Kf – molal freezing point depression constant

Calculating Molar Mass Working backwards from FP/BP formulas Working backwards from FP/BP formulas Practice Practice 34-35

Lab - Distillation Objectives: Objectives: Observe use of distillation to separate volatile and nonvolatile components of a homogeneous mixture Observe use of distillation to separate volatile and nonvolatile components of a homogeneous mixture Techniques: Techniques: Distillation setup Distillation setup Heating Mantles Heating Mantles Condensers Condensers Hypothesis: Hypothesis: Predict what you will observe with each distillate. Predict what you will observe with each distillate. Color, Odor, pH Color, Odor, pH