Phase Diagram for CO2 Phase Diagram for H2O The Liquid State Density Compressibility Diffusion Evaporation Vapor pressure Surface tension Viscosity Adhesive cohesiv e forces Capillary action Density of Ice and Water Compressibility Surface Tension Equilibrium Vapor Pressure Vapor Pressure Curves Trouton s Rule An 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 mol which is within 2 3 of the experimental value Works well for unassociated liquids and gives useful information about degree of association Trouton s Rule Nonassociated ideal liquids Hvap Tb p 88 J mol carbon tetrachloride benzene cyclohexane Associated liquids Hvap Tb p 88 J mol water 110 methanol 112 ammonia 97 Association in the vapor state Hvap Tb p 88 J mol acetic acid 62 hydrogen fluoride 26 Colligative Properties Thought Experiment Colligative Properties Elevation of the normal boiling point Lowering of the normal freezing point Elevation of the normal b p Raoult s Law Nonvolatile solute in volatile solvent p p Xsolvent p p p p Xsolute Elevation of the boiling point T Kbpm Depression of the freezing point T Kfpm Osmostic pressure cRT Boiling and Freezing Point Constants for Some Solvents Phase Diagram for H2O Colligative Properties Elevation of the normal boiling point Lowering of the normal freezing point Elevation of the normal b p Super Slurper Super Slurper Slurper molecules are polymers with hydrophilic ends that grab onto water molecules Sodium salt of poly acrylic acid R COO Na Osmosis Osmotic Pressure Applications Treating industrial wastes Pulp and paper manufacture Reclamation of brackish salt water Sewage treatment Electrodialysis Many biological ecological processes Osmosis Osmotic Pressure Osmosis Osmotic Pressure DRIED PLUMS used to be prunes Carrots Eggs Blood cells Osmosis Osmotic Pressure In dilute solutions V n2RT g2 M2 RT cRT where c mol L Solubility of hemoglobin in water is 5 0 g L Strategy LOGIC 1 80 X 10 3 atm 25 C C RT mol L MW g L mol L g mol Normal and Reverse Osmotic Systems Example Estimate 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 factor Telectrolyte i Tnonelectrolyte 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 Mixture Binary mixtures of Volatile Components Distillation Simple distillation as recorded by Maxfield Parish in his freshman chemistry laboratory notebook Fractional distillation on a laboratory scale of 1000mL h Separation of petroleum hydrocarbon mixtures on an industrial scale 50 000 gal d Benzene and Toluene form an ideal solution
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