Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings Properties of Water 9.2 Solutions 9.3 Electrolytes and Nonelectrolytes 9.6 Percent Concentration 9.7 Molarity Chapter 9 Solutions

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 2  Water is the most common solvent.  The water molecule is polar.  Hydrogen bonds form between the hydrogen atom in one molecule and the oxygen atom in a different water molecule. 9.1 Water

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 3 Water

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 4  Water for the body is obtained from fluids as well as foods.  Some foods have a high percentage of water. Water in Foods

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 5 Water molecules  At the surface form hydrogen bonds with molecules on or below the surface, which pulls them closer.  At the surface behave like a thin, elastic membrane, or “skin.”  Cannot hydrogen bond when compounds called surfactants are added. Surface Tension

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 6 Solutions Are homogeneous mixtures of two or more substances. Consist of a solvent and one or more solutes. 9.2 Solutions: Solute and Solvent

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 7 Solutes  Spread evenly throughout the solution.  Cannot be separated by filtration.  Can be separated by evaporation.  Are not visible, but can give a color to the solution. Nature of Solutes in Solutions

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 8 Examples of Solutions The solute and solvent in a solution can be a solid, liquid, and/or a gas.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 9 Identify the solute and the solvent in each. A. brass: 20 g zinc + 50 g copper solute= 1) zinc 2) copper solvent = 1) zinc 2) copper B. 100 g H 2 O + 5 g KCl solute = 1) KCl 2) H 2 O solvent = 1) KCl 2) H 2 O Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 10 Identify the solute and the solvent in each. A. brass: 20 g zinc + 50 g copper solute= 1) zinc solvent = 2) copper B. 100 g H 2 O + 5 g KCl solute = 1) KCl solvent = 2) H 2 O Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 11 Identify the solute in each of the following solutions: A. 2 g sugar (1) and 100 mL water (2) B mL of ethyl alcohol (1) and 30.0 mL of methyl alcohol (2) C mL water (1) and 1.50 g NaCl (2) D. Air: 200 mL O 2 (1) and 800 mL N 2 (2) Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 12 Identify the solute in each of the following solutions: A. 2 g sugar (1) B mL of methyl alcohol (2) C. 1.5 g NaCl (2) D. 200 mL O 2 (1) Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 13 A solution forms when there is an attraction between the particles of the solute and solvent. A polar solvent such as water dissolves polar solutes such as sugar and ionic solutes such as NaCl. A nonpolar solvent such as hexane (C 6 H 14 ) dissolves nonpolar solutes such as oil or grease. Like Dissolves Like

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 14 Examples of Like Dissolves Like SolventsSolutes Water (polar) Ni(NO 3 ) 2 (ionic) CH 2 Cl 2 (nonpolar) I 2 (nonpolar)

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 15 Which of the following solutes will dissolve in water? Why? 1) Na 2 SO 4 2) gasoline (nonpolar) 3) I 2 4) HCl Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 16 Which of the following solutes will dissolve in water? Why? 1) Na 2 SO 4 Yes, ionic 2) gasoline No, nonnpolar 3) I 2 No, nonpolar 4) HClYes, polar Most polar and ionic solutes dissolve in water because water is a polar solvent. Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 17 Formation of a Solution Na + and Cl - ions on the surface of a NaCl crystal are attracted to polar water molecules. In solution, the ions are hydrated as several H 2 O molecules surround each.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 18 When NaCl(s) dissolves in water, the reaction can be written as H 2 O NaCl(s) Na + (aq) + Cl – (aq) solid separation of ions Equations for Solution Formation

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 19 Solid LiCl is added to water. It dissolves because A. The Li + ions are attracted to the 1) oxygen atom (  – ) of water. 2) hydrogen atom (  + ) of water. B. The Cl - ions are attracted to the 1) oxygen atom (  – ) of water. 2) hydrogen atom (  + ) of water. Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 20 Solid LiCl is added to water. It dissolves because A. The Li + ions are attracted to the 1) oxygen atom (  – ) of water. B. The Cl - ions are attracted to the 2) hydrogen atom (  + ) of water. Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 21 Hydrates Hydrates are solid compounds that contain water molecules as part of the crystal structure. Heating a hydrate releases the water of hydration to give the anhydrate salt.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 22 Examples of Hydrates

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 23 Learning Check Write the equation for the dehydration of AlCl 3 6H 2 O.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 24 Solution Write the equation for the dehydration of AlCl 3 6H 2 O. AlCl 3 6H 2 O AlCl 3 + 6H 2 O

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 25 Electrolytes  Produce positive (+) and negative (-) ions when they dissolve in water.  In water conduct an electric current. 9.3 Electrolytes

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 26 Strong electrolytes ionize 100% in solution. Equations for the dissociation of strong electrolytes show the formation of ions in aqueous (aq) solutions. H 2 O 100% ions NaCl(s) Na + (aq) + Cl - (aq) H 2 O CaBr 2 (s) Ca 2+ (aq) + 2Br - (aq) Strong Electrolytes

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 27 Complete each of the following dissociation equations for strong electrolytes dissolved in water: H 2 O A. CaCl 2 (s) 1) CaCl 2 2) Ca 2+ + Cl 2 - 3) Ca Cl - H 2 O B. K 3 PO 4 (s) 1) 3K + + PO ) K 3 PO 4 3) K P 3- + O 4 - Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 28 Complete each of the following dissociation equations for strong electrolytes dissolved in water: H 2 O A. 3) CaCl 2 (s) Ca Cl - H 2 O B. 1) K 3 PO 4 (s) 3K + + PO 4 3- Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 29  A weak electrolyte  Dissolves mostly as molecules in solution.  Produces only a few ions in aqueous solutions.  Has an equilibrium that favors the reactants. HF + H 2 O H 3 O + (aq) + F - (aq) NH 3 + H 2 O NH 4 + (aq) + OH - (aq) Weak Electrolytes

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 30  Nonelectrolytes  Form only molecules in water.  Do not produce ions in water.  Do not conduct an electric current. Nonelectrolytes

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 31 The concentration of a solution is the amount of solute dissolved in a specific amount of solution. amount of solute amount of solution The percent concentration describes the amount of solute that is dissolved in 100 parts of solution. amount of solute 100 parts solution 9.6 Percent Concentration

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 32 The mass percent (%m/m) Concentration is the percent by mass of solute in a solution. mass percent = g of solute x 100% g of solution Is the g of solute in 100 g of solution. mass percent = g of solute 100 g of solution Mass Percent

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 33 grams of solute +grams of solvent 50.0 g KCl solution Mass of Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 34 Mass percent (%m/m) is calculated from the grams of solute (g KCl) and the grams of solution (g KCl solution). g of KCl = 8.0 g g of solvent (water) = 42.0 g g of KCl solution = 50.0 g 8.0 g KCl (solute) x 100 = 16% (m/m) KCl 50.0 g KCl solution Calculating Mass Percent

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 35 A solution is prepared by mixing 15 g Na 2 CO 3 and 235 g of H 2 O. Calculate the mass percent (%m/m) of the solution. 1) 15% (m/m) Na 2 CO 3 2) 6.4% (m/m) Na 2 CO 3 3) 6.0% (m/m) Na 2 CO 3 Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 36 3) 6.0% (m/m) Na 2 CO 3 mass solute = 15 g Na 2 CO 3 mass solution= 15 g g = 250 g mass %(m/m) = 15 g Na 2 CO 3 x g solution = 6.0% Na 2 CO 3 solution Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 37 The mass/volume percent (%m/v) Concentration is the ratio of the mass in grams (g) of solute in a volume (mL) of solution. mass/volume % = g of solute x 100% mL of solution Is the g of solute in 100 mL of solution. mass/volume % = g of solute 100 mL of solution Mass/Volume Percent

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 38 Preparing a Solution with a Mass/Volume % Concentration A percent mass/volume solution is prepared by weighing out the grams of solute (g) and adding water to give the final volume of the solution.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 39 Calculation of Mass/Volume Percent Mass/volume percent (%m/v) is calculated from the grams of solute (g KCl) and the volume of solution (mL KCl solution). g of KI = 5.0 g KI mL of KI solution = mL 5.0 g KI (solute) x 100 = 2.0%(m/v) KI mL KI solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 40 A 500. mL samples of an IV glucose solution contains 25 g glucose (C 6 H 12 O 6 ) in water. What is the mass/volume % (%m/v) of glucose of the IV solution? 1) 5.0% 2) 20.% 3) 50.% Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 41 1) 5.0% Mass/volume %(m/v) = 25 g glucose x mL solution = 5.0 % (m/v) glucose solution Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 42 The volume percent (%v/v) Concentration is the percent volume (mL) of solute (liquid) to volume (mL) of solution. volume % (v/v) = mL of solute x 100% mL of solution Is the mL of solute in 100 mL of solution. volume % (v/v) = mL of solute 100 mL of solution Volume Percent

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 43 Two conversion factors can be written for any type of % value. Percent Conversion Factors

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 44 Write two conversion factors for each solutions: A. 8%(m/v) NaOH B. 12%(v/v) ethyl alcohol Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 45 A. 8%(m/v) NaOH 8 g NaOH and 100 mL solution 100 mL solution 8 g NaOH B. 12%(v/v) ethyl alcohol 12 mL alcohol and 100 mL solution 100 mL solution 12 mL alcohol Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 46 How many grams of NaCl are needed to prepare 250 g of a 10.0% (m/m) NaCl solution? 1. Write the 10.0 % (m/m) as conversion factors g NaCl and 100 g solution 100 g solution 10.0 g NaCl 2. Use the factor that cancels given (g solution). 250 g solution x 10.0 g NaCl = 25 g NaCl 100 g solution Using Percent Factors

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 47 How many grams of NaOH are needed to prepare 2.0 L of a 12%(m/v) NaOH solution? 1) 24 g NaOH 2)240 g NaOH 3)2400 g NaOH Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 48 2) 240 g NaOH 2.0 L x 1000 mL = 2000 mL 1 L 2000 mL x 12 g NaOH = 240 g NaOH 100 mL 12 % (m/v) factor Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 49 How many milliliters of 5% (m/v) glucose solution are given if a patient receives 150 g of glucose? 1) 30 mL 2) 3000 mL 3) 7500 mL Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 50 2) 3000 mL 150 g glucose x 100 mL = 3000 mL 5 g glucose 5% m/v factor (inverted) Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 51 Molarity is a concentration unit for the moles of solute in the liters (L) of solution. Molarity (M) = moles of solute = moles liter of solution L Examples: 2.0 M HCl = 2.0 moles HCl 1 L 6.0 M HCl= 6.0 moles HCl 1 L 9.7 Molarity (M)

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 52 Preparing a 1.0 Molar Solution A 1.0 M NaCl solution is prepared by weighing out 58.5 g NaCl ( 1.0 mole) and adding water to make 1.0 liter of solution.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 53 What is the molarity of a NaOH solution prepared by adding 4.0 g of solid NaOH to water to make 0.50 L of solution ? 1. Determine the moles of solute. 4.0 g NaOH x 1 mole NaOH = 0.10 mole 40.0 g NaOH 2. Calculate molarity mole = 0.20 mole = 0.20 M NaOH 0.50 L 1 L Calculation of Molarity

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 54 Calculate the molarity of an NaHCO 3 solution prepared by dissolving 36 g of solid NaHCO 3 in water to give a solution volume of 240 mL. 1) 0.43 M 2) 1.8 M 3) 15 M Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 55 2) 1.8 M 36 g x 1 mole NaHCO 3 = 0.43 mole NaHCO 3 84 g 0.43 mole NaHCO 3 = 1.8 M NaHCO L Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 56 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? 1)0.20 M 2)5.0 M 3)36 M Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 57 1) 0.20 M 72 g x 1 mole x 1 = 0.20 moles 180. g 2.0 L 1 L = 0.20 M Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 58 The units in molarity can be used to write conversion factors. Molarity Conversion Factors

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 59 Stomach acid is 0.10 M HCl solution. How many moles of HCl are present in 1500 mL of stomach acid? 1) 15 moles HCl 2) 1.5 moles HCl 3) 0.15 mole HCl Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 60 3) 0.15 mole HCl 1500 mL x 1 L = 1.5 L 1000 mL 1.5 L x 0.10 mole HCl = 0.15 mole HCl 1 L Molarity factor Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 61 Calculate the grams of KCl that must be dissolved in water to prepare 0.25 L of a 2.0 M KCl solution. 1) 150 g KCl 2) 37 g KCl 3) 19 g KCl Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 62 3) 37 g KCl Determine the number of moles of KCl L x 2.0 mole KCl = 0.50 moles KCl 1 L Convert the moles to grams of KCl moles KCl x 74.6 g KCl = 37 g KCl 1 mole KCl molar mass of KCl Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 63 How many milliliters of 6.0 M HNO 3 contain 0.15 mole of HNO 3 ? 1) 25 mL 2) 90 mL 3) 400 mL Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 64 1) 25 mL 0.15 mole HNO 3 x 1 L x 1000 mL 6.0 moles HNO 3 1 L Molarity factor inverted = 25 mL HNO 3 Solution