1. Solutions

2. Solution – homogeneous mixture in which solute & solvent particles are evenly distributed in one another solvent – the dissolving medium; thing that does the dissolving solvent – the dissolving medium; thing that does the dissolving solute –the dissolved particles; thing that is dissolved solute –the dissolved particles; thing that is dissolved solutes and solvents can be solids, liquids, or gases solutes and solvents can be solids, liquids, or gases

3. Solubility – amount of solute that dissolves in a quantity of solvent at certain temperature and pressure Solutions can be: a) unsaturated – contains less solute than solvent can possibly dissolve b) saturated – contains as much solute as can be dissolved by solvent

4. c) supersaturated – contains more solute than can normally be dissolved by solvent; not very stable – slight disturbance to solution will cause solute to precipitate or crystallize

5. Terms related to solubility soluble – substance that will dissolve in a solvent soluble – substance that will dissolve in a solvent insoluble – substance that will not dissolve in a solvent insoluble – substance that will not dissolve in a solvent miscible – when 2 liquids will dissolve in each other in any proportion (ex: water and ethanol) miscible – when 2 liquids will dissolve in each other in any proportion (ex: water and ethanol) immiscible – when 2 liquids are insoluble (ex: water and oil) immiscible – when 2 liquids are insoluble (ex: water and oil)

6. Electrolytes excellent conductors in liquid state or dissolved in water (aqueous) excellent conductors in liquid state or dissolved in water (aqueous) In order for a solution to carry an electrical current, it must contain ions that are free to move. In order for a solution to carry an electrical current, it must contain ions that are free to move. –Acids, bases and ionic compounds all ionize (break into ions) in water to form free ions. http://www.schooltube.com/video/36d8205 07a4c220061eb/The-Basics-on-Electrolytes http://www.schooltube.com/video/36d8205 07a4c220061eb/The-Basics-on-Electrolytes

7. Factors Affecting Solubility agitation of the system – increases collisions between solute and solvent particles agitation of the system – increases collisions between solute and solvent particles particle size – smaller dissolves faster because more surface area particle size – smaller dissolves faster because more surface area temperature – solutes generally dissolve faster at higher temps. temperature – solutes generally dissolve faster at higher temps. – higher kinetic energy at higher temps. – stronger and more frequent collisions between solute and solvent particles - Exception: solubility of gases inversely proportional to temperature - Exception: solubility of gases inversely proportional to temperature

8. Concentration of Solutions Molarity – M – mols of solute per L of solution Molarity – M – mols of solute per L of solution Example: 5 M – dissolve 5 mol of solute in enough solvent to make 1 L of solution Example: 5 M – dissolve 5 mol of solute in enough solvent to make 1 L of solution

9. Calculating molarity (M) 1. convert mass of solute (g) to mol using molar mass 2. convert volume of solution to L 3. use formula: M = mols solute M = mols solute liters solution liters solution

10. Example 1 Example 1 –What is the molarity of 2.3 moles of sodium chloride in 0.45 liters of solution? M = mols solute liters solution liters solution M = 2.3 mol = 5.1 M 0.45 L 0.45 L

11. Example 2 What is molarity of a solution prepared by dissolving 37.94 g of KOH in H 2 O, then diluting the volume to 500 mL? mass = 37.94 g KOH 1 mol KOH = 0.676mol 56.11 g KOH molar mass KOH molar mass KOH volume = 500 mL 1 L = 0.500 L 1000 mL 1000 mL molarity = 0.676 mol = 1.35 M 0.500 L 0.500 L

12. Dilutions stock solution – mixture w/ high concentration of solute; can be diluted by adding additional solvent to get molarity needed stock solution – mixture w/ high concentration of solute; can be diluted by adding additional solvent to get molarity needed use this equation to solve for unknown: use this equation to solve for unknown: M 1 · V 1 = M 2 · V 2

13. Example What is the molarity of a solution that is made by diluting 50.0 mL of 4.74 M solution of HCl to 250.0 mL? M 1 = 4.74 M M 1 = 4.74 M V 1 = 50.0 mL V 1 = 50.0 mL M 2 = ? M 2 = ? V 2 = 250.0 mL V 2 = 250.0 mL M 1 V 1 = M 2 V 2 M 2 = 0.948 M M 2 = 0.948 M

14. “Like dissolves like” Rule I. Polar solvents dissolve ionic and polar solutes I.partial positive & negative charges of polar molecules are attractive to one another I.Due to an uneven sharing of electrons in a molecule II.polar solvents with partial + and – charges are attracted to + and – ions in ionic compounds II. Nonpolar solvents dissolve nonpolar solutes http://www.mhhe.com/physsci/chemistry/essen tialchemistry/flash/molvie1.swf http://www.mhhe.com/physsci/chemistry/essen tialchemistry/flash/molvie1.swf

15. The Uniqueness of Water! Structure of H 2 O Structure of H 2 O Lewis Dot Structure Lewis Dot Structure VSEPR Shape VSEPR Shape Electronegativity (H=2.1 and O=3.5) Electronegativity (H=2.1 and O=3.5) Hydrogen bonding Hydrogen bonding

16. Physical Properties of Water Physical Properties of Water –Density of Ice –Universal Solvent –High melting and boiling points –Cohesion (surface tension) –Adhesion (capillary action) –High specific heat (ability to hold heat) ALL OF THESE ARE DUE TO THE STUCTURE OF WATER (polar and hydrogen bonds)!!!