CHEM 135 1st Edition Lecture 4Outline of Last Lecture I. Solidsa. Cubic unit cellb. Classification of crystalline solidsOutline of Current Lecture II. Solutionsa. Definitions and componentsb. Types of formationsIII. Solubilitya. Effect of temperatureb. Effect of pressureIV.Colligative PropertiesV.Vapor Pressure and Dynamic EquilibriumVI.Raoult’s LawCurrent LectureII. a. DefinitionsSolution- a homogeneous mixture of two or more substancesSolvent- the majority component of a solutionSolute- the minority component of a solutionb. Types of FormationsEnthalpy of the solutionHsolution=Hsolute+Hsolvent+HmixH1: Separation of solute molecules- the enthalpy needed for separation is positive making this separation endothermic due to the energy required to break the bonds within the solute moleculesThese 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.H2: Separation of solvent molecules- Again, separation= (+) enthalpy/endothermic reactionH3: Formation of solute-solvent interactions- The formation of new bonds=(-) enthalpy due to the energy being released/exothermic reactionExothermic solution formationHsolute(+)+ Hsolvent(+)<Hmix (-)(releasing heat)Endothermic solution formationHsolute (+) + Hsolvent(+) >Hmix (-)  (absorbing heat)Saturated solution- contains max. amount of solute (cannot dissolve any more solute if added)Unsaturated solution- contains less solute than the max. capacity (can dissolve more solute)Supersaturated solution- contains more solute then the max. capacity (contains excess undissolved solute)III. SolubilitySolubility- the amount of solute that can dissolve in a given amount of solvent at a given temperature- When most solids are placed in water, solubility increases as temperature increaseso Why? Bonds break easier when heated, allowing for the solute to dissolve faster- Solubility of a gas in a liquid increases with increasing pressure of the gas above the liquid o Henry’s Law Sgas=kHPgasIV. Colligative Properties - These are properties that depend ONLY on the number, not the type of solute particles in a solution:o Vapor Pressure Loweringo Freezing Point Depressiono Boiling Point Elevationo Osmotic PressureV. Vapor Pressure and Dynamic Equilibrium Dynamic equilibrium- rate of evap. = rate of condensationVapor Pressure- Pressure of a gas in dynamic equilibrium with its liquid- Ex. If a non-volatile liquid (doesn’t evaporate easily) solute is added to a liquid, what happens?o Vapor pressure of solution is loweredVI. Raoult’s Law- Vapor Pressure of the solution is given by:Psolution=Xsolvent-PsolventXsolvent- mole fraction of the solvent (n solvent/n solute + n solvent)- Vapor pressure lowering