CHEM 135 1st EditionExam # 1 Study Guide Lectures: 1 - 10Lecture 1 (January 21)Chapter 11Intermolecular Forces- electrostatic attractive forces that exist between molecules, weaker than bonding forces (farther apart and not sharing electrons), molecules with stronger IMFs have higher BP- Dispersion Forces- Ion-Dipole - Dipole-Dipoleo Hydrogen Bonding Instantaneous dipole-can induce dipoles in other moleculesEx: Identify the molecule with dipole-dipole forces a.CO2b.CH3Clc. CH4d.HIDetermine the kind of IMF present in each compounda.N2 b.NH3c. Cod.CCl4Lecture 2 (January 23)Dispersion and thermal behavior (based on molar mass)- Mostly, the higher the molar mass, greater the dispersion forces (also meaning a higher boiling point)o Ex: He molar mass=4.00 g/mol BP=4.2 K and Ar molar mass=39.95 g/mol BP=87 KDispersion and thermal behavior (based on shape)- This only applies when molar masses are identical - The greater the contact surface area means greater dispersion forces resulting in a higher boiling point- Liner molecules tend to have higher boiling points versus circular due to this conceptBreakdown of Intermolecular ForcesType Present In Strength 1-4 (4=strongest)Dispersion All molecules and atoms 1Dipole-Dipole Polar molecules 2Hydrogen Bonding Molecules containing H bonded to N, O or F3Ion-Dipole Mixtures of ionic compounds and polar compounds4Ex: Place the following compounds in order of increasing strength of intermolecular forcesCH4 CH3CH2CH3 CH3CH3Place the following compounds in order of decreasing strength of intermolecular forcesHF H2 CO2Surface Tension- the tendency of liquids to minimize the surface area - Stronger IMF results in higher degrees of surface tension- Molecules at the surface are less stable- Liquids like to take the shape with the least geometrical area to minimize surface areaViscosity- the resistance of a liquid to flow - Stronger IMF, greater the viscosityPhase Changes - Gas to liquid= condensation (exo)- Liquid to gas= vaporization (endo)- Liquid to solid= freezing (exo)- Solid to liquid= melting (fusion) (endo)- Solid to gas= sublimation (endo)- Gas to solid= deposition (exo)Lecture 3 (January 26)Review the phase diagram, know how to read one and know these terms associated with them:Area: only one phase can existLine: two phases can co-existTriple point: three phases can co-existCritical point: vapor and liquid not distinguishableSolids: Crystal Lattice and unit cellLattice- regular 3-D arrangement of atoms within a crystalline solid Unit Cell- smallest repeating unit of latticeAll about cubic unit cells:- All 90˙ angles between corners of the unit cell- The length of all edges are equal - For an atom in a unit cello 1/8 of each corner atom is within the unit cello ½ of each atom on a face is within the unit cello ¼ of each atom on an edge is within the unit cello 1 of each atom inside the unit cell is within the unit cellSimple Cubic Cell (SCC)SCC=1 atom1/8 x 8 corner atoms= 1 atomBody Centered Cubic Cell (BCC)BCC=2 atoms1/8 x 8 corner atoms= 1 atom1 atom in the centerFace Centered Cubic Cell (FCC)FCC= 4 atoms1/8 x 8 corner atoms= 1 atom1/2 x 6 face atoms= 3 atomsClassification of crystalline solids- Molecular Solidso Composite units are molecules (ice)- Ionic Solidso Composite units are formula units (cations and anions) (salt)- Atomic Solids o Composite units are atoms Nonboding- held together by dispersion forces (solid xenon) Metallic- held together by metallic bonds (gold)Lecture 4 (January 28)Solution- a homogeneous mixture of two or more substancesSolvent- the majority component of a solutionSolute- the minority component of a solutionEnthalpy 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 molecules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)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=kHPgasColligative 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 PressureVapor 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 loweredRaoult’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 (P):P= Xsolvent-P solventLecture 5 (January 30)Freezing point depression and boiling point elevationThe freezing point of a solution is lower than the freezing point of the pure solventTf=m-KfThe boiling point of a solution is higher than the boiling point of the pure solvent. - Tb=m-Kbm= molality of a solution in moles solute per kilogram solventKf, Kb- freezing point depression and boiling point elevation constantsEx: 1. Calculate the freezing point of a 1.7 m aqueous glycol solution2. What mass of ethylene glycol (C2H6O2), in grams, must be added to 1.0 kg of water to producea solution that boils at 105.0 ˚C?Lecture 6 (February 2)Osmosis is the flow of solvent from a solution of low concentration into a solution of high