Phase Diagram for CO2Phase Diagram for H2OThe Liquid StateDensity of Ice and WaterCompressibilitySurface TensionEquilibrium Vapor PressureVapor Pressure CurvesTrouton’s RuleTrouton’s RuleColligative Properties-Thought Experiment -Colligative PropertiesElevation of the normal b.p.Raoult’s LawBoiling and Freezing Point Constants for Some SolventsPhase Diagram for H2OColligative PropertiesElevation of the normal b.p.Super SlurperSuper SlurperOsmosis/Osmotic PressureOsmosis/Osmotic PressureOsmosis/Osmotic PressureOsmosis/Osmotic PressureNormal and Reverse Osmotic SystemsExampleVan’t Hoff i-FactorVan’t Hoff i-factorAnother Estimate ProblemSimple DistillationPartial Pressures and Total Pressure in a Binary MixtureBinary mixtures of Volatile ComponentsDistillationBenzene and Toluene form an ideal solutionPhase Diagram for CO2Phase Diagram for H2OThe Liquid State•Density• Compressibility• Diffusion•Evaporation•Vapor pressure• Surface tension• Viscosity• Adhesive/cohesive forces• Capillary actionDensity of Ice and WaterCompressibilitySurface TensionEquilibrium Vapor PressureVapor Pressure CurvesTrouton’s RuleAn interesting and useful “approximation:• Says that the ratio of the heat of vaporization and the boiling point is (roughly) constant.∆Hvap/Tb.p. ~ 88 J/mol• Boiling point of cyclohexane is 69°C. Therefore, ∆Hvap= (69 + 273)(88) ~ 30 kJ/molwhich is within 2-3% of the experimental value.• Works well for unassociated liquids and gives useful information about degree of association.Trouton’s RuleNonassociated (ideal) liquids, ∆Hvap/Tb.p. ~ 88 J/molcarbon tetrachloridebenzenecyclohexaneAssociated liquids, ∆Hvap/Tb.p. > 88 J/molwater (110)methanol (112)ammonia (97)Association in the vapor state, ∆Hvap/Tb.p. < 88 J/molacetic acid (62)hydrogen fluoride (26)Colligative Properties-Thought Experiment -Colligative Properties• Elevation of the normal boiling point• Lowering of the normal freezing pointElevation of the normal b.p.Raoult’s Law• Nonvolatile solute in volatile solvent:p = p°Xsolventp° - p = ∆p= p°Xsolute• Elevation of the boiling point: ∆T = Kbpm• Depression of the freezing point: ∆T = Kfpm• Osmostic pressure: Π = cRTBoiling and Freezing Point Constants for Some SolventsPhase Diagram for H2OColligative Properties• Elevation of the normal boiling point• Lowering of the normal freezing pointElevation of the normal b.p.Super SlurperSuper Slurper• “Slurper” molecules are polymers with hydrophilic ends that grab onto water molecules.• Sodium salt of poly(acrylic acid).•R-COO-, Na+Osmosis/Osmotic PressureApplications:– Treating industrial wastes– Pulp and paper manufacture– Reclamation of brackish/salt water– Sewage treatment– Electrodialysis– Many biological/ecological processesOsmosis/Osmotic PressureOsmosis/Osmotic Pressure• DRIED PLUMS… (used to be“prunes”)• Carrots• Eggs• Blood cellsOsmosis/Osmotic PressureIn dilute solutions:∏V = n2RT = [g2/M2]RT∏ = cRT where c ~ mol/LSolubility of hemoglobin in water is 5.0 g/LStrategy/LOGIC?∏ = 1.80 X 10-3atm @ 25°CC = ∏ /RT = mol/LMW = [g/L]/mol/L] = g/molNormal and Reverse Osmotic SystemsExampleEstimate the “back pressure” needed to obtain pure water from sea water by “reverse” osmosis.Strategy/LOGIC?Van’t Hoff i-Factor• Colligative effects depend on number of particles.•Ionization and dissociation multiply colligative effects.• Association acts in the opposite sense.Van’t Hoff i-factori =∆Telectrolyt∆Tnonelectro∆T = iKbpm (boiling point elevation)∆T = iKfpm (freezing point depression)∏ = icRT (osmotic pressure)Another Estimate Problem• …. the lowest temperature your car radiator fluid could withstand and still remain fluid if your car radiator fluid was… VODKA!•Strategy/LOGIC?Simple Distillation• Mixture of benzene and toluene form a nearly ideal solution.• Use Raoult’s law to calculate the composition of the solution.• Use Dalton’s law to calculate the composition of the vapor above the solution• Vapor is “richer” in the more volatile component.Partial Pressures and Total Pressure in a Binary MixtureBinary mixtures of Volatile ComponentsDistillation• Simple distillation…as recorded by Maxfield Parish in his freshman chemistry laboratory notebook.• Fractional distillation…on a laboratory scale of 1000mL/h • Separation of petroleumhydrocarbon mixtures on anindustrial scale ~50,000 gal/dBenzene and Toluene form an ideal
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