1. Chapter 12, pp 401-424 Solutions

2. Types of Mixtures Homogeneous mixtures - Solutions Solvent = dissolving medium (like water) Solute = substance dissolved (like sugar) May exist as liquid, gas, or solid (alloys) Heterogeneous mixtures

3. Mixtures Homogeneous - Solutions Heterogeneous –Suspensions: particles settle out –Colloids: dispersion Emulsions – milk, mayonnaise, cheese, butter Foam – shaving cream, whipped cream Gels - gelatin Aerosol – smoke, fog, clouds, mist, exhaust Sol – paints, mud

4. Solutes Electrolytes –Conducts electricity in aqueous sol’n –Salts (NaCl, HCl, MgBr 2, etc…) Nonelectrolytes –Does NOT conduct electricity –Sugars, nonpolar molecules

5. Solution Process Factors affecting rate of dissolution –Surface area of solute –Kinetic energy (agitation) –Temperature (usually heat is better) –Concentration (amount of solute per solvent) –Polar vs. nonpolar (“Like dissolves like.”) –Pressure (gas in liquids) Henry’s Law

6. Enthalpies of Solution Changes in molecular bonds are required  Solute-solute; solvent-solvent Solvation involves changes in energy –Heat absorbed by solution (endothermic) KI dissolved in water feels cold –Heat released by solution (exothermic) NaOH dissolved in water feels warm

7. Concentrations of Sol’n Molarity –Moles of solute/ Liter of sol’n  “M” Molality –Moles of solute/ Kilogram of solvent  “m” Normality (FYI) –One gram equivalent of solute/ Liter of sol’n  “N”

8. Saturation Saturated = contains max am’t of solute Unsaturated = less than max amount Supersaturated = more than saturated –Heat solvent as solute is added –Leave undisturbed –Crystal formation returns sol’n to equilibrium

9. Saturation Curve Mass (grams) per 100g H 2 O vs. Temperature 20 40 60 0 020406080100  Saturated Supersaturated Unsaturated Temperature, o C Grams per 100g H 2 O

10. Solubility Curve