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Aqueous Reactions and Solution Stoichiometry. CDO High School. Solute and solvent. Solute: the substance that is dissolved in another substance Solvent : the substance that something is dissolved into it. Concentrated vs Dilute.
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Aqueous Reactions and Solution Stoichiometry CDO High School
Solute and solvent • Solute: the substance that is dissolved in another substance • Solvent: the substance that something is dissolved into it
Concentrated vs Dilute • Concentration: refers to how much solute is dissolved in the solvent • Concentrated: solutions with a large amount of solute dissolved in solvent • Dilute: solutions with a small amount of solute dissolved the solvent
moles of solute Molarity (M) = volume of solution in liters Molarity • Two solutions can contain the same compounds but be quite different because the proportions of those compounds are different. • Molarity is one way to measure the concentration of a solution.
Units of Molarity 2.0 M HCl = 2.0 moles HCl 1 L HCl solution 6.0 M HCl = 6.0 moles HCl 1 L HCl solution LecturePLUS Timberlake
Molarity Calculation NaOH is used to remove potato peels commercially. If 4.0 g NaOH are used to make 500. mL of NaOH solution, what is the molarity (M) of the solution? LecturePLUS Timberlake
Calculating Molarity 1) 4.0 g NaOH ÷ 40.0 g/mol NaOH = 0.10 mole NaOH 2) 500. mL x 1 L _ = 0.500 L 1000 mL 3) 0.10 mole NaOH = 0.20 mole NaOH = 0.20 M NaOH 0.500 L 1 L LecturePLUS Timberlake
Learning Check M1 A KOH solution with a volume of 400 mL contains 2 mole KOH. What is the molarity of the solution? Drano LecturePLUS Timberlake
Learning Check M2 A glucose solution with a volume of 2.0 L contains 72 g glucose (C6H12O6). If glucose has a molar mass of 180. g/mole, what is the molarity of the glucose solution? LecturePLUS Timberlake
Learning Check M3 Stomach acid is a 0.10 M HCl solution. How many moles of HCl are in 1500 mL of stomach acid solution? LecturePLUS Timberlake
Learning Check M4 How many grams of KCl are present in 2.5 L of 0.50 M KCl? LecturePLUS Timberlake
Solution M4 3) 2.5 L x 0.50 mole x 74.6 g KCl = 93 g KCl 1 L 1 mole KCl LecturePLUS Timberlake
Learning Check M5 How many milliliters of stomach acid, which is 0.10 M HCl, contain 0.15 mole HCl? LecturePLUS Timberlake
Learning Check M6 How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution? LecturePLUS Timberlake
Solution Stoichiometry • The majority of work in research and industry involves solutions. Recall that solutions are easy to handle and are usually easier to control in reactions. • Solution stoichiometry – the procedure for calculating the molar concentration or volume of solution products or reactants
Mass A (g) Volume A (L) Volume B (L) ÷ Molarity A ÷ MolarMass X MolarMass ÷ Molarity B X Molarity B X Molarity A X MoleRatio Mole A (mol) Mole B (mol) X MoleRatio ÷ Volume B ÷ Volume A Molarity A (M) Molarity B (M) X Volume B X Volume A X MolarMass ÷ MolarMass Mass B (g)
Example #1 • Ammonia and phosphoric acid solutions are used to produce ammonium hydrogen phosphate fertilizer. What volume of 14.8 M NH3(aq) is needed to react with 1000 L of 12.9 M of H3PO4(aq)? • 2NH3(aq) + H3PO4(aq) (NH4)2HPO4(aq) 1000 L x 12.9 mol x 2mol ÷ 14.8 mol/L = 1740 L 1 L 1mol
Example #2 • In an experiment, .01000 L sample of sulfuric acid solution reacts completely with 0.0159 L of 0.150 M potassium hydroxide. Calculate the concentration of the sulfuric acid. • H2SO4(aq) + 2KOH(aq) 2H2O(l) + K2SO4(aq) 0.0159 L x 0.150 mol x 1mol x 1 = 0.119 mol/L 1 L 2 mol 0.0100 L
Example #3 • How many grams of silver chromate will form when 120 mL of 0.500 M silver nitrate are added to potassium chromate? 2 AgNO3(aq) + K2CrO4(aq) Ag2CrO4(s) + 2 KNO3(aq)
Example #4 • If you mix 200 ml of 0.100 M Pb(NO3)2 and 300 ml of 0.200 M MgCl2, how much PbCl2 precipitate will you form? Pb(NO3)2(aq) + 2MgCl2(aq) PbCl2(s) + Mg(NO3)2(aq)
