CHEM 1120 1nd Edition Lecture 2Outline of Last Lecture I. Intro to ChapterII. Intermolecular forcesa. Difference between intermolecular and intramolecular forcesb. 6 types of intermolecular forcesc. Gas and Solid solutionsd. Why do substances dissolve?III. Heat of Solutiona. Equation: Heat of solute + Heat of solvent + Heat of mixingIV. The Solution Process and Entropya. Why not all processes are exothermicb. Saturated, unsaturated, and supersaturated solutionsOutline of Current Lecture V. Solubility and SaturationVI. Effects of Pressure and Temperature on Solubilitya. Temperaturei. Solid solutionsii. Gaseous solutionsb. Gas Solubility and PressureVII. 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)VIII. Colligative Propertiesa. Vapor pressure loweringb. Raoult’s LawCurrent LectureI. Solubility and Saturationa. Solubility: maximum amount of solute dissolved in a given amount of solvent at temperature TThese 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.b. Unsaturated: less solute than can dissolve in the solvent at temperature T is dissolved in the solventc. Supersaturated: the solvent hold more solute than is normally possible at that temperatured. Saturated: most solute that the solvent can possibly hold, more solvent that unsaturated, less than supersaturatede. “Like dissolves like”-similar things dissolve. Good rule of thumb for solubility!II. Effects of Pressure and Temperature on Solubilitya. Temperaturei. For most ionic SOLIDS, the heat of solution is endothermic1. Higher temperature=greater solubility (Some exceptions) (For SOLIDS)ii. Systems try to be as disorganized as they can within a given temperature and pressureiii. For GASES, the heat of solution is exothermic1. Higher temperature=lower solubility (For GASES)b. Gas Solubility and Pressurei. Henry’s Law: gas solubility is directly proportional to the gas’ pressure over the solution1. Solubility of gas (mol/L) = k (mol/Latm) x Pressure of the gas (atm)2. Double pressure, double solubilityIII. Concentration Unitsa. Concentration and strength are different!i. Can have a very concentrated solution of a weak acidii. Concentration: quantity of solute in a given mass or volume of a solutioniii. Strength: how much is disassociates b. Molarity (M)i. Molarity = Moles of solute/Liters of Solutionii. Densities of liquids are slightly temperature dependent, therefore molarity is temperature dependentiii. Favorite of chemistsc. Molality (m)i. Molality = moles of solute/kilograms of solventii. SOLVENT not solutioniii. Independent of temperatured. Mass Percent (% w/w)i. Mass % = (Mass of component/total mass of solution) x 100e. Volume Percent (% v/v)i. Volume % = (volume of component/volume of solution) x 100ii. Need densities to solve equationsf. Mole fraction (X)i. Mole fraction of A = moles of A/total moles of all componentsg. Parts per million (ppm) and Parts per billion (ppb)i. Ppm of component = (Mass of component/total mass of solution) x 10^6ii. Ppb of component = (mass of component/total mass of solution) x 10^9iii. Note: percent (%) = parts per hundredh. Concentration Unit Interconversionsi. Must know how to do! (did not cover how to do it in lecture)IV. Colligative Propertiesa. Statistical properties that deal with solutionsb. When rules don’t happen, something interesting is happening chemicallyc. Colligative properties: solution properties that depend ONLY upon the NUMBER of the solute particles, not their nature or identityi. Examples1. Vapor pressure lowering2. Osmosis3. Freezing point depression4. Boiling point elevationd. Vapor pressure loweringi. The vapor pressure of a solution’s solvent is less than the vapor pressure of the pure solventii. Raoult’s Law: Pa = XaPoa1. Pa = solvent v.p.2. Xa = solvent mole fraction3. Poa = pure solvent v.p. iii. Boil when vapor pressure = outside pressureiv. Review section 11.5 in