1 Chapter 12 Solutions 12.1 Solutions Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

2 Solute and Solvent Solutions Are homogeneous mixtures of two or more substances. Consist of a solvent and one or more solutes. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

3 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 © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

4 Examples of Solutions The solute and solvent can be a solid, liquid, and/or a gas. Table 12.3 Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

5 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

6 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

7 Water Is the most common solvent. Is a polar molecule. Forms hydrogen bonds between the hydrogen atom in one molecule and the oxygen atom in a different water molecule. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

8 Formation of a Solution Na + and Cl - ions On the surface of a NaCl crystal are attracted to polar water molecules. In solution are hydrated as several H 2 O molecules surround each. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

9 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

10 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

11 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

12 Two substances form a solution When there is an attraction between the particles of the solute and solvent. When a polar solvent such as water dissolves polar solutes such as sugar and ionic solutes such as NaCl. When a nonpolar solvent such as hexane (C 6 H 14 ) dissolves nonpolar solutes such as oil or grease. Like Dissolves Like

13 Water and a Polar Solute Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

14 Like Dissolves Like Solvents Solutes Water (polar) Ni(NO 3 ) 2 C 2 H 2 Cl 2 (nonpolar) (polar) I 2 (nonpolar) Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

15 Will the following solutes dissolve in water? Why? 1) Na 2 SO 4 2) gasoline (nonpolar) 3) I 2 4) HCl Learning Check

16 Will the following solutes dissolve in water? Why? 1) Na 2 SO 4 Yes, ionic 2) gasoline No, nonpolar 3) I 2 No, nonpolar 4) HClYes, polar Most polar and ionic solutes dissolve in water because water is a polar solvent. Solution