General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Review: 1

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Evaporation vs. Vaporization Vaporization- the process by which a liquid or solid changes to gas. Evaporation- is the process where particles escape from the surface of a non boiling liquid and enters the gas state.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Evaporation  ~Evaporation takes place because the particles of liquids have different kinetic energies, therefore some of the particles with higher kinetic energy overcome the intermolecular forces and evaporate to go in the gas phase.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Boiling and Pressure  Boiling- is the change of a liquid to bubbles or vapor. Boiling occurs when the vapor pressure becomes equals atmospheric pressure.  A liquid boils at the temp. at which its vapor pressure is equal to the pressure above its surface. (usually atmospheric pressure)  If the pressure above the liquid’s surface is 1 atm, then this temperature is called as its “Normal Boiling Point”

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Boiling and Pressure  B.P. of a liquid is reduced by lowering the pressure above it.  Why does it take longer to cook at high altitudes?  As the Pressure goes DOWN, the boiling point goes DOWN. (It boils easier)

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 6 Chapter 8 Solutions 8.1 Solutions

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 7 Solutions: Solute and Solvent Solutions  are homogeneous mixtures of two or more substances  consist of a solvent and one or more solutes

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 8 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

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Insoluble and Soluble After each of these substances, determine if it is soluble or insoluble.  Sand  Salt  Sugar  Rice

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 10 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

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 11 Identify the solute in each of the following solutions: A. sugar (1) B. methyl alcohol (2) C. NaCl (2) D. O 2 (1) Solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 12 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

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Solute (salt) Solvent (water) A Salt Water Solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. In a salt water solution…  Is salt the solute or the solvent?  Solute  Is water the solute or the solvent?  Solvent  What does the solute do?  Gets dissolved  What does the solvent do?  Does the dissolving

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 15 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 by many H 2 O molecules surrounding each ion

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 16 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

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 17 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

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 18 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

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 19 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/or 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

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 20 Will each of the following solutes dissolve in water? Why or why not? 1) Na 2 SO 4 2) gasoline (nonpolar) 3) I 2 4) HCl Learning Check

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 21 Will each of the following solutes dissolve in water? Why or why not? 1) Na 2 SO 4 Yes. The solute is ionic. 2) gasoline No. The solute is nonpolar. 3) I 2 No. The solute is nonpolar. 4) HClYes. The solute is polar. Most polar and ionic solutes dissolve in water because water is a polar solvent. Solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. solute solvent solute solvent What is the Solute and what is the solvent? Label Each. 1.Cigarette Smoke and Air 2.Caffeine and Water (Cup of Coffee) 3.Water and Oxygen (Water in a Fish Tank) 4.Carbon Dioxide and Sugar Water (Sealed Can of Pop) 5.Oxygen and Nitrogen (Air) 6.Minerals and Water (Hard Water) 7.Water and Sugar (Maple Syrup) 8.Acetic Acid and Water (Vinegar) 9.Salt and Water (Ocean Water) 10.Make your own

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Unsaturated Vs. Saturated  unsaturated: This means that if you were to add more solute to the liquid, it would keep dissolving. For example, if you take one teaspoon of salt and put it in a bucket of water, you've made an unsaturated solution.  An unsaturated solution is one in which more of the solute could dissolve at the same temperature. 23

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Unsaturated vs. Saturated  saturated: This means that the liquid has dissolved all of the solute that is possible.  When this happens, it means that the solution is saturated, because no more sugar could dissolve.  i.e. putting WAY too much sugar in water 24