Current LectureMolecular RecognitionProcess by which molecules interact with other molecules in living tissues to produce a biological effectEx: Ethylene (ripening agent)Delocalization of electronsSpreading of electrons in alternating single and double bonds over three or more atoms in a moleculeSection 6.1Attractive ForcesIntramolecular or bonding forces are found within a molecule. The chemical behavior of each phase of matter is the same because the same basic particle is present in each case.H2O molecules are present whether the substance is in the solid, liquid, or gas phase.Intermolecular or nonbonding forces are found between molecules. The physical behavior of each phase of matter is different because the strength of these forces differ from state to state.Kinetic Molecular View of 3 StatesAttractive Forces vs. Kinetic EnergyPropertiesSolidAttractive foces are weak relative to kinetic energyParticles are far apart. A gas has no fixed shape or volume.LiquidAttractive forces are stronger because particles have less kinetic energyA liquid can flow and change shape, but has a fixed volume.GasAttractions . . . .Particles are fixed in place relative to each otherA solid has a fixed shape and volumeInteractions of Nonpolar MoleculesDispersion (London) Forces:Intermolecular force between nonpolar molecules caused by the presence of temporary dipoles in the moleculesTemporary Dipole (Induced Dipole)Separation of charge produced in an atom or molecule by a momentary uneven distribution of electronsPolarizabilityRelative ease with which the electron cloud in a molecule, ion, or atom can be distorted, inducing a temporary dipoleDispersion ForcesDispersion = Momentary shift in e- densityInduced DipolesProximity of polar molecule = Dipole – induced dipoleStrength of Dispersion ForceFactors Affecting Strength of Dispersion:Size of Atoms/ Molecules:Larger atoms/molecules more polarizable than smaller atoms/moleculesDispersion increases with PolarizabilityShape of Molecules:Increased surface area = increased interactions between moleculesLinear molecules have higher dispersion than branched molecules of similar MWUnsaturated fatty acids- bentImportance of ShapeConstitutional isomers: same formulas, different connections between atoms in moleculeHigher surface area molecules, stronger interactionsStrength of interactions affects physical and chemical propertiesViscosity- measure of resistance to flow of a fluidFactors: Molecular shape, molar mass, and temperatureCHEM 111 1nd Edition Lecture 20 Outline of Last Lecture I. Atomic Orbital and BondsII. Hybridization Outline of Current Lecture II. Molecular RecognitionIII. Attractive ForcesIV. Interactions of Nonpolar MoleculesV. Strength of Dispersion ForceCurrent Lecture Molecular Recognition- Process by which molecules interact with other molecules in living tissues to producea biological effect- Ex: Ethylene (ripening agent) Delocalization of electrons- Spreading of electrons in alternating single and double bonds over three or more atoms in a molecule Section 6.1 Attractive Forces- Intramolecular or bonding forces are found within a molecule. The chemical behavior of each phase of matter is the same because the same basic particle is present in each case.o H2O molecules are present whether the substance is in the solid, liquid, or gas phase.- Intermolecular or nonbonding forces are found between molecules. The physical behavior of each phase of matter is different because the strength of these forces differ from state to state.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. Kinetic Molecular View of 3 StatesAttractive Forces vs. Kinetic EnergyPropertiesSolid Attractive foces are weak relative to kinetic energyParticles are far apart. A gas has no fixed shape or volume.Liquid Attractive forces are stronger because particles have less kinetic energyA liquid can flow and change shape, but has a fixed volume.Gas Attractions . . . .Particles are fixed in place relative to each otherA solid has a fixed shape and volume Interactions of Nonpolar Molecules Dispersion (London) Forces:- Intermolecular force between nonpolar molecules caused by the presence of temporary dipoles in the molecules Temporary Dipole (Induced Dipole)- Separation of charge produced in an atom or molecule by a momentary uneven distribution of electrons Polarizability- Relative ease with which the electron cloud in a molecule, ion, or atom can be distorted, inducing a temporary dipole Dispersion Forces- Dispersion = Momentary shift in e- density Induced Dipoles- Proximity of polar molecule = Dipole – induced dipole Strength of Dispersion Force Factors Affecting Strength of Dispersion:- Size of Atoms/ Molecules:o Larger atoms/molecules more polarizable than smaller atoms/moleculeso Dispersion increases with Polarizability- Shape of Molecules: o Increased surface area = increased interactions between moleculeso Linear molecules have higher dispersion than branched molecules of similar MW Unsaturated fatty acids- bent Importance of Shape- Constitutional isomers: same formulas, different connections between atoms in molecule- Higher surface area molecules, stronger interactions- Strength of interactions affects physical and chemical properties Viscosity- measure of resistance to flow of a fluidFactors: Molecular shape, molar mass, and