Aqueous Reactions Aqueous Reactions and Solution Stoichiometry CDO High School

Aqueous Reactions Solute and solvent  Solute: the substance that is dissolved in another substance  Solvent: the substance that something is dissolved into it

Aqueous Reactions 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

Aqueous Reactions 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. moles of solute volume of solution in liters Molarity (M) =

Aqueous Reactions 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 5LecturePLUS Timberlake

Aqueous Reactions 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? 6LecturePLUS Timberlake

Aqueous Reactions Calculating Molarity 1) 4.0 g NaOH ÷ 40.0 g/mol NaOH = 0.10 mole NaOH 2) 500. mL x 1 L _ = L 1000 mL 3) 0.10 mole NaOH = 0.20 mole NaOH = 0.20 M NaOH L 1 L 7LecturePLUS Timberlake

Aqueous Reactions Learning Check M1 A KOH solution with a volume of 400 mL contains 2 mole KOH. What is the molarity of the solution? 8LecturePLUS Timberlake Drano

Aqueous Reactions Learning Check M2 A glucose solution with a volume of 2.0 L contains 72 g glucose (C 6 H 12 O 6 ). If glucose has a molar mass of 180. g/mole, what is the molarity of the glucose solution? 9LecturePLUS Timberlake

Aqueous Reactions 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? 10LecturePLUS Timberlake

Aqueous Reactions Learning Check M4 How many grams of KCl are present in 2.5 L of 0.50 M KCl? 11LecturePLUS Timberlake

Aqueous Reactions Solution M4 3) 2.5 L x 0.50 mole x 74.6 g KCl = 93 g KCl 1 L 1 mole KCl 12LecturePLUS Timberlake

Aqueous Reactions Learning Check M5 How many milliliters of stomach acid, which is 0.10 M HCl, contain 0.15 mole HCl? 13LecturePLUS Timberlake

Aqueous Reactions Learning Check M6 How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution? 14LecturePLUS Timberlake

Aqueous Reactions 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

Aqueous Reactions Mole A (mol) Mole B (mol) Mass A (g) Mass B (g) Volume B (L) Molarity B (M) Volume A (L) Molarity A (M) X Mole Ratio X Molar Mass÷ Molar Mass X Molar Mass X Molarity A X Molarity B ÷ Molarity B ÷ Molarity A X Volume A X Volume B ÷ Volume A ÷ Volume B

Aqueous Reactions Example #1  Ammonia and phosphoric acid solutions are used to produce ammonium hydrogen phosphate fertilizer. What volume of 14.8 M NH 3(aq) is needed to react with 1000 L of 12.9 M of H 3 PO 4(aq) ?  2NH 3(aq) + H 3 PO 4(aq)  (NH 4 ) 2 HPO 4(aq) 1000 L x 12.9 mol x 2mol ÷ 14.8 mol/L = 1740 L 1 L 1mol

Aqueous Reactions Example #2  In an experiment, L sample of sulfuric acid solution reacts completely with L of M potassium hydroxide. Calculate the concentration of the sulfuric acid.  H 2 SO 4(aq) + 2KOH (aq)  2H 2 O (l) + K 2 SO 4(aq) L x mol x 1mol x 1 = mol/L 1 L 2 mol L

Aqueous Reactions Example #3  How many grams of silver chromate will form when 120 mL of M silver nitrate are added to potassium chromate? 2 AgNO 3(aq) + K 2 CrO 4(aq)  Ag 2 CrO 4(s) + 2 KNO 3(aq)

Aqueous Reactions Example #4  If you mix 200 ml of M Pb(NO 3 ) 2 and 300 ml of M MgCl 2, how much PbCl 2 precipitate will you form? Pb(NO 3 ) 2(aq) + 2MgCl 2(aq)  PbCl 2(s) + Mg(NO 3 ) 2(aq)