Chapter 15 Review

Quiz To make the soap, I prepared a 40% by mass solution of NaOH. How did I make 1000g of solution? Describe measurements and procedures. NaOH is a solid. To make the soap, I prepared a 40% by mass solution of NaOH. How did I make 1000g of solution? Describe measurements and procedures. NaOH is a solid. Wear Lab Coat and Goggles (2 pts) Wear Lab Coat and Goggles (2 pts) Measure out 600 ml of distilled water (600g) into a large flask (2 pts) Measure out 600 ml of distilled water (600g) into a large flask (2 pts) Weigh 400 g of NaOH (2 Pts) Weigh 400 g of NaOH (2 Pts) This gives me This gives me 400 g NaOH/(400g + 600g) x 100 = 40% 400 g NaOH/(400g + 600g) x 100 = 40% Pour the NaOH slowly into the water while stirring (2 pts). It gets very HOT! Pour the NaOH slowly into the water while stirring (2 pts). It gets very HOT!

Saponification Definition: Usually, a process by which triglycerides are reacted with sodium or potassium hydroxide to produce glycerol and a fatty acid salt, called 'soap'. Definition: Usually, a process by which triglycerides are reacted with sodium or potassium hydroxide to produce glycerol and a fatty acid salt, called 'soap'.

Saponification

Why Do We Need the Ammonia? Ammonia contains an “Ammonium” ion Ammonia contains an “Ammonium” ion What is an ammonium ion like? What is an ammonium ion like? Why do we need positive ions after the mixing? Why do we need positive ions after the mixing? To balance any remaining OH - ions To balance any remaining OH - ions

Things to Remember What is “Solvation”? What is “Solvation”? How does it occur? How does it occur? What has to happen for it to occur? What has to happen for it to occur? How do you change the rate of solvation? How do you change the rate of solvation? “Solvation” and “Dissolution” are the same “Solvation” and “Dissolution” are the same Text uses “solvation”. Test uses “dissolution”. Text uses “solvation”. Test uses “dissolution”. Vocabulary Terms Vocabulary Terms Solute, solvent Solute, solvent Saturated, unsaturated, supersaturated Saturated, unsaturated, supersaturated Solubility, soluble, insoluble, miscible, immiscible Solubility, soluble, insoluble, miscible, immiscible

Things to Remember Like Dissolves Like Like Dissolves Like Polar solvents dissolve polar or ionic solutes Polar solvents dissolve polar or ionic solutes Non-polar solvents dissolve non-polar solutes Non-polar solvents dissolve non-polar solutes Alcohols and soaps dissolve both because they have both parts Alcohols and soaps dissolve both because they have both parts Abbreviations: Abbreviations: M means Molar = moles/liter of solution M means Molar = moles/liter of solution m means Molal = moles/Kg solvent m means Molal = moles/Kg solvent % by mass = mass solute/mass of solution % by mass = mass solute/mass of solution % by volume = volume of solute/volume of solution % by volume = volume of solute/volume of solution

Examples What is the molality of a solution that contains 31.0 g HCl in 5.00 kg of water? What is the molality of a solution that contains 31.0 g HCl in 5.00 kg of water? Molality = moles/kg solvent Molality = moles/kg solvent 31.0g HCl x 1 mol/35.5g = mol HCl 31.0g HCl x 1 mol/35.5g = mol HCl m = mol HCl/5.00 kg = m m = mol HCl/5.00 kg = m

Examples How many moles of HCl are present in 0.70 L of a 0.33 M HCl solution How many moles of HCl are present in 0.70 L of a 0.33 M HCl solution M means Molar = Moles/Liter solution M means Molar = Moles/Liter solution 0.33M = ? moles/0.70L 0.33M = ? moles/0.70L ?moles = 0.33mol/liter x 0.70L ?moles = 0.33mol/liter x 0.70L = 0.23 moles HCl = 0.23 moles HCl

Examples The concentration of a water solution of NaCl is 2.48 m and it contains 806 g of water. How many grams of NaCl is in the solution? The concentration of a water solution of NaCl is 2.48 m and it contains 806 g of water. How many grams of NaCl is in the solution? m = molality = moles/kg solvent m = molality = moles/kg solvent 806 g x 1 kg/1000 g = 0.806kg water 806 g x 1 kg/1000 g = 0.806kg water 2.48 m = ?moles/0.806kg 2.48 m = ?moles/0.806kg ?moles = 2.48 m x kg = 2.00 moles ?moles = 2.48 m x kg = 2.00 moles 2.00 moles NaCl x 58.5g NaCl/mole = 117g NaCl 2.00 moles NaCl x 58.5g NaCl/mole = 117g NaCl

Examples A solution contains 85.0 g of NaNO 3 and has a volume of 750 ml. What is the molarity of the solution? A solution contains 85.0 g of NaNO 3 and has a volume of 750 ml. What is the molarity of the solution? Molarity = moles/L Molarity = moles/L 750 ml x 1 L/1000 ml = L solution 750 ml x 1 L/1000 ml = L solution 85.0 g NaNO 3 x 1 mole/85 g = 1 mole NaNO g NaNO 3 x 1 mole/85 g = 1 mole NaNO 3 Molarity = 1 mole/0.750 L = 1.33 M NaNO 3 Molarity = 1 mole/0.750 L = 1.33 M NaNO 3