CHEM 1120 1st Edition Lecture 3 Outline of Last Lecture I. Solubility and SaturationII. Effects of Pressure and Temperature on Solubilitya. Temperaturei. Solid solutionsii. Gaseous solutionsb. Gas Solubility and PressureIII. Concentration Unitsa. Molarity (M)b. Molality (m)c. Mass Percent (% w/w)d. Volume Percent (% v/v)e. Mole Fraction (X)f. Parts per million (ppm) and Parts per billion (ppb)IV. Colligative Propertiesa. Vapor pressure loweringb. Raoult’s LawOutline of Current Lecture I. Colligative Properties Continued from Last Lecturea. Vapor Pressure lowering continuedb. Boiling Point Elevation and Freezing Point Depressionc. OsmosisII. Colligative Properties of Electrolyte solutionsa. Dependent on number of ionsIII. Colloidsa. What they areb. Tyndall EffectThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.c. Hydrophilic and Hydrophobic colloidsIV. Begin Chapter 14-Intro to chapterCurrent LectureI. Colligative Properties Continueda. Vapor Pressure lowering continuedi. Change in Pa = Xb x Poa1. A = solvent2. B = soluteii. Change in Pa  vapor pressure loweringiii. Strong solute-solvent interactions  NEGATIVE deviations from Raoult’s Law, and vice versab. Boiling Point Elevation and Freezing Point Depressioni. Change in boiling point elevation = molal BP elevation constant x molality1. Tb = Kb x mii. Change in freezing point depression = molal FP depression constant x molality1. Tf = Kf x miii. Tb and Tf depends on solvent NOT soluteiv. To find freezing point1. Calculate Change in Tf, and subtract that number from normal freezing pointc. Osmosisi. Examples1. Nutrient transport in plants and animals2. Limp carrots regain their crispiness in water3. Cucumbers shrivel to become pickles in brine4. Meat is preserved in salt (bacteria dehydrated)5. Water is purified (reverse osmosis)ii. Osmosis: diffusion of solvent through a semi-permeable membrane into asolution of higher concentrationiii. Semipermeable membrane: a membrane that allows passage of solvent molecules but not solute moleculesiv. Osmotic Pressure (pi)1. Pi(V)=nRT2. Similar to ideal gas law3. Osmotic pressure=MRT4. M  molarityv. Osmosis in blood cells1. Osmotic pressure is same on both sides = isotonic2. Solute concentration outside is greater than inside = hypertonic (cell depletes)3. Solute concentration outside is less than inside = hypotonic (Cell bursts)II. Colligative Properties of Electrolyte Solutionsa. Salt solutions and the NUMBER of solute particlesi. NaCl  Na + Cl (1 mol  2 mol)ii. Depends on particlesiii. Number of ions per formula unit is importantiv. Electrolytes do not COMPLETELY dissociatev. Van’t Hoff Factor = i = Change in Tf (measured) / Change in Tf (expected for nonelectrolyte)1. More charge, more likely to have ionic association2. Lower concentration, closer to theoreticalvi. VP lowering: Pa = I x Xb x Poavii. PB elevation: Tb = I x Kb x mviii. FB depression Tf = I x Kf x m ix. Osmotic pressure: pi = I x M x R x TIII. Colloidsa. Suspension: a heterogeneous mixture with dispersed particles large enough to be seenb. Colloid: a mixture with dispersed particles larger than a solution’s but smaller than a suspensionsi. Particle diameter (in nm) 1-1000ii. Example: fog/clouds (about 600 nm), butter, marshmallows, paint, whipped cream, milkiii. Colloids do not have to be liquids!c. Tyndall Effecti. Colloidal suspensions can scatter rays of light-known as Tyndall Effectd. Hydrophilic and hydrophobic colloidsi. Hydrophilic-water loving1. Easily dispersed in water2. Core may be hydrophobic but as long as surface is hydrophilic, it isdispersed in waterii. Hydrophobic-water fearing1. Must be stabilized by ions absorbed on the particle’s surface or by hydrophilic groups in the particles surfaceIV. CHAPTER 14 START-Chemical KineticsV. Chapter Introa. Thermodynamics only tells you if it should happen but doesn’t tell you how longb. How can we modify reactions to go