1 Chapter 7 Solutions 7.1 Solutions Copyright © 2009 by Pearson Education, Inc.

2 Solute and Solvent Solutions are homogeneous mixtures of two or more substances. consist of a solvent and one or more solutes.

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 © 2009 by Pearson Education, Inc.

4 Examples of Solutions The solute and solvent in a solution can be a solid, liquid, and/or a gas. Copyright © 2009 by Pearson Education, Inc.

5 Identify the solute in each of the following solutions. A. 2 g of sugar and 100 mL of water B mL of ethyl alcohol and 30.0 mL of methyl alcohol C mL of water and 1.50 g of NaCl D. Air: 200 mL of O 2 and 800 mL of N 2 Learning Check

6 Identify the solute in each of the following solutions. A. 2 g of sugar B mL of methyl alcohol C. 1.5 g of NaCl D. 200 mL of O 2 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 © 2009 by Pearson Education, Inc.

8 Formation of a Solution Na + and Cl - ions on the surface of a NaCl crystal are attracted to polar water molecules. are hydrated in solution with many H 2 O molecules surrounding each ion. Copyright © 2009 by Pearson Education, Inc.

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 © 2009 by Pearson Education, Inc.

14 Like Dissolves Like Solvents Solutes Water (polar) Ni(NO 3 ) 2 CH 2 Cl 2 (nonpolar) (polar) I 2 (nonpolar) Copyright © 2009 by Pearson Education, Inc.

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

16 Which of the following solutes will 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