Chapter 11: Liquids and Solids and Intermolecular ForcesPhases of MatterPowerPoint PresentationIntermolecular versus bonding forcesDipole-Dipole InteractionHydrogen BondingThe boiling points of the covalent hydrides of elements in Groups 4A, 5A, 6A, and 7A.ExampleDispersion ForcesSlide 10Slide 11Example – Which atom/molecule in each pair have higher boiling points?Ion-Dipole InteractionsInduced Dipole InteractionsReviewIonic BondsDetermining Most Important Intermolecular Force between 2 or more moleculesExamples“Like Dissolves Like”Liquids and Intermolecular Forces: Surface TensionLiquids and Intermolecular Forces: ViscosityPhase ChangesVaporizationVapor Pressure and Dynamic EquilibriumVapor Pressure and Intermolecular ForcesTemperature Dependence of Vapor Pressure and Boiling PointPhase DiagramsA Typical Phase DiagramUnusual Phases of MatterSlide 30Problem: Determine the phases of matter for the following points on the phase diagram of CO2 . following conditions?Chapter 11 1Chapter 11: Liquids and Solidsand Intermolecular ForcesGeorgia Gwinnett CollegeChem 1212KFall 2013(B. Shepler)Phases of Matter•SOLIDS–Have rigid shape, fixed volume. External shape can reflect the atomic and molecular arrangement.•Reasonably well understood•LIQUIDS–Have no fixed shape and but do have a fixed volume•Not well understood•GASES–Expand to fill their container. No fixed shape or volume•Good theoretical understandingChapter 11 3Intermolecular versus bonding forcesChapter 11 4•Bonding Forces–Chemical bonds (covalent, ionic, metallic)•Strong•Directional•Short Range (relative)•Intermolecular Forces•Weaker than chemical bonds, usually much weaker•Less directional than covalent bonds, more directional than ionic bonds•Longer range than covalent bonds but at shorter range than ionic bonds•Condensed Phases–Solids and Liquids–Intermolecular forces: mutual attractions hold the molecules closer together than gasesSometimes call covalent bonds intramolecular forcesDipole-Dipole Interaction5•A dipole-dipole interaction occurs when both molecules have a dipole moment.•Consider the molecule acetone: CH3COCH3•The partial positive end of one molecule, is attracted to the partial negative,  end of another molecule.–This is a dipole-dipole interaction!Hydrogen Bonding•Hydrogen bonds are a special type of dipole-dipole interaction.•It occurs between an H bonded to an O, N, or F on one molecule and an O, N, or F on another molecule.•Stronger than typical dipole-dipole interactions.The boiling points of the covalent hydrides of elements in Groups 4A, 5A, 6A, and 7A.Chapter 11 7Importance of Hydrogen BondingExample•Illustrate the dipole-dipole interaction that occur between multiple molecules of dimethyl ether, CH3OCH3.•Can molecules of dimethyl ether hydrogen bond to one another?•Can a molecule of dimethyl ether hydrogen bond to a molecule of water?Chapter 11 8Dispersion Forces•Dispersion Forces (London Dispersion Forces)–Result of fluctuations in the electron distribution within molecules or atoms.–At one instant the electrons may be unevenly distributed. Chapter 11 9Chapter 11 10The instantaneous dipole moment on one atom/molecule induces an instantaneous dipole moment on another atom/molecule. The instantaneous dipole moments then attract each otherDispersion Forces•(London) dispersion forces –The weakest intermolecular force.–Exist between all atoms/molecules – even if they also possess stronger intermolecular forces.–Polarizability•The ability of the electron cloud to be distorted. More polarizable means greater dispersion forces.•Tends to increase with atom/molecular size–larger electron clouds.–Cations are significantly less polarizable than their parent atom.–The shape of a molecule can effect the dispersion forces.Chapter 11 11Example – Which atom/molecule in each pair have higher boiling points?1. Ne or Xe?2. Chapter 11 12Ion-Dipole InteractionsChapter 11 13•Ion-dipole interactions–Occur between an ion, such as Na+, and any polar compound.Induced Dipole InteractionsChapter 11 14•ion-induced dipole interactions or dipole-induced dipole interactions–The electron “cloud” of a molecule can be distorted by a nearby electric field.–Results in a temporary induced dipole moment.Argon AtomArgon AtomReviewChapter 11 15Ionic BondsChapter 11 16•No molecules in ionic compounds.No molecules in ionic compounds.–Ionic bonds can be considered both Ionic bonds can be considered both intermolecular and intramolecular!intermolecular and intramolecular!•Strongest of intermolecular forcesStrongest of intermolecular forces–400 to 4000 kJ/mole400 to 4000 kJ/mole•Explains why ionic solids tend to have Explains why ionic solids tend to have HIGH melting points temperaturesHIGH melting points temperaturesDetermining Most Important Intermolecular Force between 2 or more molecules•Draw the Lewis Structures•Determine Bond Polarities•Use Geometry/Shape to determine molecule polarity, identify possibility of H-bonding etc.Chapter 11 17Examples•Determine the primary intermolecular forces that are present in a sample of each of the following: BaBr2, CH3COOH, NH3, H2S, and SiH4, and CH2ClBr.Chapter 11 18“Like Dissolves Like”Chapter 11 19Liquids and Intermolecular Forces: Surface TensionChapter 11 20Liquids and Intermolecular Forces: ViscosityChapter 11 21Phase ChangesChapter 11 22GASSOLIDLIQUIDVaporization•Vaporization and Condensation•Factors that effect the rate of vaporization:–Temperature:–Surface Area:–Intermolecular Forces:Chapter 11 23Vapor Pressure and Dynamic Equilibrium•Dynamic Equilibrium: When two opposite processes react at the same rate. Not net gain or loss of material.•Vapor pressure: Pressure of gas in dynamic equilibrium with its liquidChapter 11 24Vapor Pressure and Intermolecular Forces•Which of the following compounds has the greater vapor pressure at 25 °C?–Water–Dimethyl Ether (CH3OCH3)–Ethanol (CH3CH2OH)Chapter 11 25Temperature Dependence of Vapor Pressure and Boiling Point•Boiling Point: temperature at which the vapor pressure equals the external pressure(atmospheric)–Molecules in the interior of the liquid can break free from the intermolecular forces.•Normal Boiling Point: Temperature at which the vapor pressure equals 1 atm (760 torr)Chapter 11 26Phase Diagrams•We have seen in this chapter that the phase of a