___________________________________ Slide 1 ___________________________________ ___________________________________ Chapter 15 ___________________________________ Solutions ___________________________________ ___________________________________ ___________________________________ Slide Chapter 15 2 Table of Contents 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 ___________________________________ ___________________________________ Solubility Solution Composition: An Introduction Solution Composition: Mass Percent Solution Composition: Molarity Dilution Stoichiometry of Solution Reactions Neutralization Reactions Solution Composition: Normality ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Copyright © Cengage Learning. All rights reserved Slide 2 ___________________________________ Chapter 15 3 ___________________________________ What is a Solution? • Solution – homogeneous mixture Solvent – substance present in largest amount Solutes – other substances in the solution Aqueous solution – solution with water as the solvent ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 3 Slide Section 15.1 4 Solubility ___________________________________ ___________________________________ Various Types of Solutions ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.1 5 Solubility 4 ___________________________________ ___________________________________ Solubility of Ionic Substances • Ionic substances breakup into individual cations and anions. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.1 6 Solubility 5 ___________________________________ ___________________________________ Solubility of Ionic Substances • Polar water molecules interact with the positive and negative ions of a salt. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 6 Slide Section 15.1 7 Solubility ___________________________________ ___________________________________ Solubility of Polar Substances • Ethanol is soluble in water because of the polar OH bond. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.1 8 Solubility 7 ___________________________________ ___________________________________ Solubility of Polar Substances • Why is solid sugar soluble in water? ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.1 9 Solubility 8 ___________________________________ ___________________________________ Substances Insoluble in Water • • Nonpolar oil does not interact with polar water. Water-water hydrogen bonds keep the water from mixing with the nonpolar molecules. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 9 Slide Section 15.1 10 Solubility ___________________________________ ___________________________________ How Substances Dissolve • • • A “hole” must be made in the water structure for each solute particle. The lost water-water interactions must be replaced by water-solute interactions. “like dissolves like” ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.1 11 Solubility 10 ___________________________________ ___________________________________ Concept Check ___________________________________ Which of the following solutes will generally not dissolve in the specified solvent? Choose the best answer. (Assume all of the compounds are in the liquid state.) ___________________________________ ___________________________________ a) b) c) d) CCl4 mixed with water (H2O) NH3 mixed with water (H2O) CH3OH mixed with water (H2O) N2 mixed with methane (CH4) ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.2 12 Solution Composition: An Introduction 11 ___________________________________ ___________________________________ • The solubility of a solute is limited. Saturated solution – contains as much solute as will dissolve at that temperature. Unsaturated solution – has not reached the limit of solute that will dissolve. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 12 ___________________________________ Slide Section 15.2 13 Solution Composition: An Introduction ___________________________________ • Supersaturated solution – occurs when a solution is saturated at an elevated temperature and then allowed to cool but all of the solid remains dissolved. Contains more dissolved solid than a saturated solution at that temperature. Unstable – adding a crystal causes precipitation. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 13 ___________________________________ Slide Section 15.2 14 Solution Composition: An Introduction ___________________________________ • • Solutions are mixtures. Amounts of substances can vary in different solutions. Specify the amounts of solvent and solutes. Qualitative measures of concentration concentrated – relatively large amount of solute dilute – relatively small amount of solute ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 14 ___________________________________ Slide Section 15.3 15 Solution Composition: Mass Percent ___________________________________ Mass percent = Mass percent = ___________________________________ mass of solute 100% mass of solution ___________________________________ grams of solute 100% grams of solute + grams of solvent ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 15 ___________________________________ Slide Section 15.3 16 Solution Composition: Mass Percent ___________________________________ Exercise ___________________________________ What is the percent-by-mass concentration of glucose in a solution made my dissolving 5.5 g of glucose in 78.2 g of water? ___________________________________ ___________________________________ 6.6% ___________________________________ [5.5 g / (5.5 g + 78.2 g)] × 100 = 6.6% glucose ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 16 ___________________________________ Slide Section 15.4 17 Solution Composition: Molarity ___________________________________ • Molarity (M) = moles of solute per volume of solution in liters: ___________________________________ ___________________________________ moles of solute M = Molarity = liters of solution 3 M HCl = ___________________________________ 6 moles of HCl 2 liters of solution ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 17 ___________________________________ Slide Section 15.4 18 Solution Composition: Molarity ___________________________________ Exercise ___________________________________ You have 1.00 mol of sugar in 125.0 mL of solution. Calculate the concentration in units of molarity. ___________________________________ ___________________________________ 8.00 M ___________________________________ 1.00 mol / (125.0 / 1000) = 8.00 M ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 18 ___________________________________ Slide Section 15.4 19 Solution Composition: Molarity ___________________________________ Exercise ___________________________________ A 500.0-g sample of potassium phosphate is dissolved in enough water to make 1.50 L of solution. What is the molarity of the solution? 1.57 M ___________________________________ ___________________________________ ___________________________________ 500.0 g is equivalent to 2.355 mol K3PO4 (500.0 g / 212.27 g/mol). The molarity is therefore 1.57 M (2.355 mol/1.50 L). ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 19 ___________________________________ Slide Section 15.4 20 Solution Composition: Molarity ___________________________________ Exercise ___________________________________ You have a 10.0 M sugar solution. What volume of this solution do you need to have 2.00 mol of sugar? ___________________________________ ___________________________________ 0.200 L ___________________________________ 2.00 mol / 10.0 M = 0.200 L ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 20 ___________________________________ Slide Section 15.4 21 Solution Composition: Molarity ___________________________________ Exercise ___________________________________ Consider separate solutions of NaOH and KCl made by dissolving 100.0 g of each solute in 250.0 mL of solution. Calculate the concentration of each solution in units of molarity. 10.0 M NaOH ___________________________________ ___________________________________ ___________________________________ [100.0 g NaOH / 39.998 g/mol] / [250.0 / 1000] = 10.0 M NaOH 5.37 M KCl ___________________________________ [100.0 g KCl / 74.55 g/mol] / [250.0 / 1000] = 5.37 M KCl Return to TOC Copyright © Cengage Learning. All rights reserved 21 ___________________________________ Slide Section 15.4 22 Solution Composition: Molarity ___________________________________ Concept Check ___________________________________ You have two HCl solutions, labeled Solution A and Solution B. Solution A has a greater concentration than Solution B. Which of the following statements are true? a) b) c) d) If you have equal volumes of both solutions, Solution B must contain more moles of HCl. If you have equal moles of HCl in both solutions, Solution B must have a greater volume. To obtain equal concentrations of both solutions, you must add a certain amount of water to Solution B. Adding more moles of HCl to both solutions will make them less concentrated. Copyright © Cengage Learning. All rights reserved ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC 22 ___________________________________ Slide Section 15.4 23 Solution Composition: Molarity ___________________________________ Concentration of Ions • For a 0.25 M CaCl2 solution: CaCl2 → Ca2+ + 2Cl– ___________________________________ ___________________________________ Ca2+: Ca2+ 1 × 0.25 M = 0.25 M – Cl : 2 × 0.25 M = 0.50 M Cl–. ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 23 ___________________________________ Slide Section 15.4 24 Solution Composition: Molarity ___________________________________ Concept Check ___________________________________ Which of the following solutions contains the greatest number of ions? a) b) c) d) 400.0 300.0 200.0 800.0 mL of 0.10 mL of 0.10 mL of 0.10 mL of 0.10 ___________________________________ M NaCl. M CaCl2. M FeCl3. M sucrose. ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 24 Slide Section 15.4 25 Solution Composition: Molarity ___________________________________ ___________________________________ Let’s Think About It • Where are we going? • ___________________________________ To find the solution that contains the greatest number of moles of ions. ___________________________________ How do we get there? Draw molecular level pictures showing each solution. Think about relative numbers of ions. How many moles of each ion are in each solution? ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.4 26 Solution Composition: Molarity 25 ___________________________________ ___________________________________ Notice • The solution with the greatest number of ions is not necessarily the one in which: the volume of the solution is the largest. the formula unit has the greatest number of ions. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.4 27 Solution Composition: Molarity 26 ___________________________________ ___________________________________ Standard Solution • A solution whose concentration is accurately known. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 27 Slide Section 15.4 28 Solution Composition: Molarity ___________________________________ ___________________________________ To Make a Standard Solution • • • Weigh out a sample of solute. Transfer to a volumetric flask. Add enough solvent to mark on flask. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.5 29 Dilution 28 ___________________________________ ___________________________________ • • • The process of adding water to a concentrated or stock solution to achieve the molarity desired for a particular solution. Dilution with water does not alter the numbers of moles of solute present. Moles of solute before dilution = moles of solute after dilution M1V1 = M2V2 ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.5 30 Dilution 29 ___________________________________ ___________________________________ Diluting a Solution • • Transfer a measured amount of original solution to a flask containing some water. Add water to the flask to the mark (with swirling) and mix by inverting the flask. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 30 Slide Section 15.5 31 Dilution ___________________________________ ___________________________________ Concept Check A 0.50 M solution of sodium chloride in an open beaker sits on a lab bench. Which of the following would decrease the concentration of the salt solution? Add water to the solution. Pour some of the solution down the sink drain. Add more sodium chloride to the solution. Let the solution sit out in the open air for a couple of days. e) At least two of the above would decrease the concentration of the salt solution. ___________________________________ ___________________________________ a) b) c) d) Copyright © Cengage Learning. All rights reserved Slide Section 15.5 32 Dilution ___________________________________ ___________________________________ ___________________________________ Return to TOC 31 ___________________________________ ___________________________________ Exercise ___________________________________ What is the minimum volume of a 2.00 M NaOH solution needed to make 150.0 mL of a 0.800 M NaOH solution? ___________________________________ ___________________________________ 60.0 mL ___________________________________ M1V1 = M2V2 (2.00 M)(V1) = (0.800 M)(150.0 mL) ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.6 33 Stoichiometry of Solution Reactions 32 ___________________________________ ___________________________________ Steps for Solving Stoichiometric Problems Involving Solutions 1. Write the balanced equation for the reaction. For reactions involving ions, it is best to write the net ionic equation. 2. Calculate the moles of reactants. 3. Determine which reactant is limiting. 4. Calculate the moles of other reactants or products, as required. 5. Convert to grams or other units, if required. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 33 ___________________________________ Slide Section 15.6 34 Stoichiometry of Solution Reactions ___________________________________ Concept Check (Part I) ___________________________________ 10.0 mL of a 0.30 M sodium phosphate solution reacts with 20.0 mL of a 0.20 M lead(II) nitrate solution (assume no volume change). What precipitate will form? ___________________________________ ___________________________________ lead(II) phosphate, Pb3(PO4)2 ___________________________________ What mass of precipitate will form? 1.1 g Pb3(PO4)2 ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 34 ___________________________________ Slide Section 15.6 35 Stoichiometry of Solution Reactions ___________________________________ Let’s Think About It • Where are we going? • ___________________________________ To find the mass of solid Pb3(PO4)2 formed. How do we get there? ___________________________________ What are the ions present in the combined solution? What is the balanced net ionic equation for the reaction? What are the moles of reactants present in the solution? Which reactant is limiting? What moles of Pb3(PO4)2 will be formed? What mass of Pb3(PO4)2 will be formed? ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 35 ___________________________________ Slide Section 15.6 36 Stoichiometry of Solution Reactions ___________________________________ Concept Check (Part II) ___________________________________ 10.0 mL of a 0.30 M sodium phosphate solution reacts with 20.0 mL of a 0.20 M lead(II) nitrate solution (assume no volume change). ___________________________________ ___________________________________ What is the concentration of nitrate ions left in solution after the reaction is complete? ___________________________________ ___________________________________ 0.27 M Return to TOC Copyright © Cengage Learning. All rights reserved 36 Slide Section 15.6 37 Stoichiometry of Solution Reactions ___________________________________ ___________________________________ Let’s Think About It • Where are we going? • ___________________________________ To find the concentration of nitrate ions left in solution after the reaction is complete. ___________________________________ How do we get there? What are the moles of nitrate ions present in the combined solution? What is the total volume of the combined solution? ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 37 ___________________________________ Slide Section 15.6 38 Stoichiometry of Solution Reactions ___________________________________ Concept Check (Part III) ___________________________________ 10.0 mL of a 0.30 M sodium phosphate solution reacts with 20.0 mL of a 0.20 M lead(II) nitrate solution (assume no volume change). ___________________________________ ___________________________________ What is the concentration of phosphate ions left in solution after the reaction is complete? ___________________________________ ___________________________________ 0.011 M Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.6 39 Stoichiometry of Solution Reactions 38 ___________________________________ ___________________________________ Let’s Think About It • Where are we going? • ___________________________________ To find the concentration of phosphate ions left in solution after the reaction is complete. ___________________________________ How do we get there? What are the moles of phosphate ions present in the solution at the start of the reaction? How many moles of phosphate ions were used up in the reaction to make the solid Pb3(PO4)2? How many moles of phosphate ions are left over after the reaction is complete? What is the total volume of the combined solution? Copyright © Cengage Learning. All rights reserved ___________________________________ ___________________________________ ___________________________________ Return to TOC 39 ___________________________________ Slide Section 15.7 40 Neutralization Reactions ___________________________________ • • • An acid-base reaction is called a neutralization reaction. Steps to solve these problems are the same as before. For a strong acid and base reaction: H+(aq) + OH–(aq) H2O(l) ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 40 ___________________________________ Slide Section 15.7 41 Neutralization Reactions ___________________________________ Concept Check ___________________________________ For the titration of sulfuric acid (H2SO4) with sodium hydroxide (NaOH), how many moles of sodium hydroxide would be required to react with 1.00 L of 0.500 M sulfuric acid? ___________________________________ ___________________________________ 1.00 mol NaOH ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.7 42 Neutralization Reactions 41 ___________________________________ ___________________________________ Let’s Think About It • Where are we going? • ___________________________________ To find the moles of NaOH required for the reaction. ___________________________________ How do we get there? What are the ions present in the combined solution? What is the reaction? What is the balanced net ionic equation for the reaction? What are the moles of H+ present in the solution? How much OH– is required to react with all of the H+ present? ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 42 Slide Section 15.8 43 Solution Composition: Normality ___________________________________ ___________________________________ Unit of Concentration • • • One equivalent of acid – amount of acid that furnishes 1 mol of H+ ions. One equivalent of base – amount of base that furnishes 1 mol of OH ions Equivalent weight – mass in grams of 1 equivalent of acid or base. ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.8 44 Solution Composition: Normality 43 ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.8 45 Solution Composition: Normality 44 ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 45 ___________________________________ Slide Section 15.8 46 Solution Composition: Normality ___________________________________ Normality = N = ___________________________________ number of equivalents equivalents equiv = = 1 liter of solution liter L ___________________________________ • To find number of equivalents: N V= ___________________________________ equiv L = equiv L ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide Section 15.8 47 Solution Composition: Normality 46 ___________________________________ ___________________________________ Concept Check ___________________________________ If Ba(OH)2 is used as a base, how many equivalents of Ba(OH)2 are there in 4 mol Ba(OH)2? a) b) c) d) ___________________________________ ___________________________________ 2 4 8 16 ___________________________________ ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved Slide 48 47 ___________________________________ Section 15.8 Solution Chapter 15Composition: Homework Normality ___________________________________ Homework ___________________________________ • Reading assignment – Pages 475 through 502 ___________________________________ • Homework Problems – Questions and problems 3, 5, 7, 11, 17, 19, 21, 23, 25, 27, 31, 35, 37, 39, 41, 43, 45, 47, 49, 51, 57, 59, 61, 71, 73, 85, 87. ___________________________________ ___________________________________ • Due on ___________________________________ Return to TOC Copyright © Cengage Learning. All rights reserved 48