CHEM 1120 Edition 1nd Lecture 2 Outline of Last Lecture I Intro to Chapter II Intermolecular forces a Difference between intermolecular and intramolecular forces b 6 types of intermolecular forces c Gas and Solid solutions d Why do substances dissolve III Heat of Solution a Equation Heat of solute Heat of solvent Heat of mixing IV The Solution Process and Entropy a Why not all processes are exothermic b Saturated unsaturated and supersaturated solutions Outline of Current Lecture V Solubility and Saturation VI Effects of Pressure and Temperature on Solubility a Temperature i Solid solutions ii Gaseous solutions b Gas Solubility and Pressure VII Concentration Units a 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 Properties a Vapor pressure lowering b Raoult s Law Current Lecture I Solubility and Saturation a Solubility maximum amount of solute dissolved in a given amount of solvent at temperature T These 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 II III b Unsaturated less solute than can dissolve in the solvent at temperature T is dissolved in the solvent c Supersaturated the solvent hold more solute than is normally possible at that temperature d Saturated most solute that the solvent can possibly hold more solvent that unsaturated less than supersaturated e Like dissolves like similar things dissolve Good rule of thumb for solubility Effects of Pressure and Temperature on Solubility a Temperature i For most ionic SOLIDS the heat of solution is endothermic 1 Higher temperature greater solubility Some exceptions For SOLIDS ii Systems try to be as disorganized as they can within a given temperature and pressure iii For GASES the heat of solution is exothermic 1 Higher temperature lower solubility For GASES b Gas Solubility and Pressure i Henry s Law gas solubility is directly proportional to the gas pressure over the solution 1 Solubility of gas mol L k mol Latm x Pressure of the gas atm 2 Double pressure double solubility Concentration Units a Concentration and strength are different i Can have a very concentrated solution of a weak acid ii Concentration quantity of solute in a given mass or volume of a solution iii Strength how much is disassociates b Molarity M i Molarity Moles of solute Liters of Solution ii Densities of liquids are slightly temperature dependent therefore molarity is temperature dependent iii Favorite of chemists c Molality m i Molality moles of solute kilograms of solvent ii SOLVENT not solution iii Independent of temperature d Mass Percent w w i Mass Mass of component total mass of solution x 100 e Volume Percent v v i Volume volume of component volume of solution x 100 ii Need densities to solve equations f Mole fraction X i Mole fraction of A moles of A total moles of all components g Parts per million ppm and Parts per billion ppb IV i Ppm of component Mass of component total mass of solution x 10 6 ii Ppb of component mass of component total mass of solution x 10 9 iii Note percent parts per hundred h Concentration Unit Interconversions i Must know how to do did not cover how to do it in lecture Colligative Properties a Statistical properties that deal with solutions b When rules don t happen something interesting is happening chemically c Colligative properties solution properties that depend ONLY upon the NUMBER of the solute particles not their nature or identity i Examples 1 Vapor pressure lowering 2 Osmosis 3 Freezing point depression 4 Boiling point elevation d Vapor pressure lowering i The vapor pressure of a solution s solvent is less than the vapor pressure of the pure solvent ii Raoult s Law Pa XaPoa 1 Pa solvent v p 2 Xa solvent mole fraction 3 Poa pure solvent v p iii Boil when vapor pressure outside pressure iv Review section 11 5 in book v