Slide 1Slide 2Types of Intermolecular Interactions (Forces)Slide 4Hydrogen BondingSlide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Effect of IMF’s and Boiling PointIntermolecular Forces and Physical CharacteristicsVaporizationVapor PressureVapor Pressure DefinitionVapor PressureVapor PressureSlide 22Slide 23Vapor PressureSlide 25Slide 26Slide 27Slide 28Clausius-Clapeyron EquationSlide 30Slide 31Slide 32Carbon tetrabromide is more volatile than carbon tetrachloride.Slide 34Slide 35Slide 36CHEM 1212 Spring 2017 Chapter 11Intermolecular Forces and the Liquid StateTypes of Intermolecular Interactions (Forces)•Ion - Ion•Dipole – Dipole•Hydrogen Bonds•London Dispersion Forces (Induced Dipoles)Hydrogen Bonding•Hydrogen bonding is a special case of a dipole-dipole interaction.•A hydrogen is bound to a VERY electronegative element (N, O, or F) and can then form a hydrogen bond with a neighboring N, O, or F.Each of the bonds below has one element with a partial negative, -, and one with a partial positive charge, +. - and + are opposite in sign but equal in magnitude. Which of these bonds has the largest partial charges on one of the atoms?A. N-HB. C-HC. H-FD. B-HE. H-HRank the following molecules from least to most polar ignore molecular weight differences.A. CH4B. CH3FC. CH3ClD. CH3BrDetermine the major IMF for each of these molecules and then rank those IMFs in order of increasing strength.A. CO2B. NH3C. CHCl3D. CCl4Which of the following compounds exhibit hydrogen bonding in the pure liquid?A. H2OB. CH3OCH3C. CH3CH2OHD. CH3NH2E. N(CH3)3F. CH3CO2HA sodium ion would have the greatest interaction with which molecule?A. CH4B. CH3ClC. CH2Cl2D. CHCl3E. CCl4Rank the compounds in order of increasing polarity.A. HClB. HBrC. HIRank the compounds in order of increasing boiling point.A. HClB. HBrC. HIWhy is the trend reversed?A. The trend for polarity was wrongB. Boiling point is not dependent on the polarity of the moleculesC. London forcesD. Boiling point is more dependent on mass than intermolecular attractionsE. Boiling point is dependent on the interaction of strange attractorsRank the compounds in order of increasing polarity.A. HClB. HBrC. HIRank the compounds in order of increasing boiling point.D. HCl, D=1.08, bp -85 CE. HBr, D=0.80, bp -66 CF. HI, D=0.42, bp -35 C HF, D=1.91, bp 19.5 CEffect of IMF’s and Boiling PointIntermolecular Forces and Physical CharacteristicsMost of the physical characteristics of solids and liquids are dependent upon the strength of the intermolecular forces keeping things together.–Heat of hydration (Chapter 13)–Vaporization–Vapor Pressure–Boiling Point–Surface Tension–ViscosityVaporization•Vaporization is the process where a particle in the liquid phase escapes in the gas phase.•Condensation is the reverse process.•As the temperature increases more particles will have enough energy to overcome the intermolecular forces holding them in the liquid phase and escape into the gas phase.Vapor Pressure•Suppose the liquid sample is in a closed container.•Some particles will have enough energy to escape from the liquid phase into the gas phase.•Some of the particles in the gas phase won’t have enough energy to escape the attractive forces when they collide with the liquid surface and condense.Vapor Pressure DefinitionThe pressure exerted by a vapor in equilibrium with its solid or liquid at a given temperature in a closed system.Vapor Pressure•A liquid is said to boil when its vapor pressure is equal to the external pressure.•The normal boiling point is when the vapor pressure is equal to 1 atm or 760 torr.Vapor PressureAs the intermolecular forces increase between particles, the vapor pressure _________ and the normal boiling point _________.A. increases, increasesB. increases, decreasesC. decreases, increasesD. decreases, decreasesAccording to this plot increasing the temperature will _____ the vapor pressure:A. increaseB. not changeC. decreaseVapor PressureThe equilibrium vapor pressure is the pressure exerted by the vapor in equilibrium with the liquid.The vapor pressure of liquid bromine at room temperature is 168 torr. Suppose that bromine is introduced drop by drop into a closed system containing air at 775 torr and room temperature. (The volume of liquid bromine is negligible compared to the volume of the system.) If the bromine is added until no more vaporizes and a few drops of liquid are present in the flask, what would be the total pressure?What would be the total pressure if the volume of this closed system were decreased to one half its original value at the same temperature?Volume does not affect vapor pressure! The liquid in a container is in equilibrium with the vapor. When the volume is decreased, some of the vapor in the container condenses to the liquid state.Vapor PressureClausius-Clapeyron EquationEstimate the vapor pressure at any temperature•The vapor pressure of 1-propanol is 10.00 torr at 14.70 °C. Calculate the vapor pressure at 52.80 °C. (Heat of vaporization of 1-propanol = 47.2 kJ/mol)Gasoline is a mixture of hydrocarbons, a major component of which is octane (CH3CH2CH2CH2CH2CH2CH2CH3). Octane has a vapor pressure of 13.95 torr at 25 °C and a vapor pressure of 144.78 torr at 75 C. Calculate the heat of vaporization of octane in kJ/mol.Carbon tetrabromide is more volatile than carbon tetrachloride.A. TrueB. FalseCarbon tetrabromide has a higher boiling point than carbon tetrachloride.A. TrueB. FalseCarbon tetrabromide has weaker IMF’s than carbon tetrachloride.A. TrueB. FalseCarbon tetrabromide has a higher vapor pressure than carbon tetrachloride.A. TrueB.