1. 1 Chapter 7 Solutions and Colloids 7.1 Physical States of Solutions Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

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

3. 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 © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

4. 4 Examples of Solutions The solute and solvent in a solution can be a solid, liquid, and/or a gas.

5. 5 Identify the solute in each of the following solutions. A. 2 g sugar and 100 mL water B. 60.0 mL of ethyl alcohol and 30.0 mL of methyl alcohol C. 55.0 mL water and 1.50 g NaCl D. Air: 200 mL O 2 and 800 mL N 2 Learning Check

6. 6 Identify the solute in each of the following solutions. A. 2 g sugar B. 30.0 mL of methyl alcohol C. 1.5 g NaCl D. 200 mL O 2 Solution

7. 7 Water (formation of the hydrated ion) 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. Hydrated ion, an ion in solution that surrounded by water molecules Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

8. 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.

9. 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. 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. 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. 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. 13 Water and a Polar Solute

14. 14 Like Dissolves Like Solvents Solutes Water (polar) Ni(NO 3 ) 2 CH 2 Cl 2 (nonpolar) (polar) I 2 (nonpolar)

15. 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. 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