无机化学英文ppt课件：chapter11.ppt

Copyright Cengage Learning.All rights reserved,2,Various Types of Solutions,Copyright Cengage Learning.All rights reserved,3,Solution Composition,Copyright Cengage Learning.All rights reserved,4,Molarity,Copyright Cengage Learning.All rights reserved,5,Mass Percent,Copyright Cengage Learning.All rights reserved,6,Mole Fraction,Copyright Cengage Learning.All rights reserved,7,Molality,Formation of a Liquid Solution,Separating the solute into its individual components(expanding the solute).Overcoming intermolecular forces in the solvent to make room for the solute(expanding the solvent).Allowing the solute and solvent to interact to form the solution.,Copyright Cengage Learning.All rights reserved,8,Steps in the Dissolving Process,Copyright Cengage Learning.All rights reserved,9,Steps in the Dissolving Process,Steps 1 and 2 require energy,since forces must be overcome to expand the solute and solvent.Step 3 usually releases energy.Steps 1 and 2 are endothermic,and step 3 is often exothermic.,Copyright Cengage Learning.All rights reserved,10,Enthalpy(Heat)of Solution,Enthalpy change associated with the formation of the solution is the sum of the H values for the steps:Hsoln=H1+H2+H3Hsoln may have a positive sign(energy absorbed)or a negative sign(energy released).,Copyright Cengage Learning.All rights reserved,11,Enthalpy(Heat)of Solution,Copyright Cengage Learning.All rights reserved,12,Explain why water and oil(a long chain hydrocarbon)do not mix.In your explanation,be sure to address how H plays a role.,Copyright Cengage Learning.All rights reserved,13,CONCEPT CHECK!,The Energy Terms for Various Types of Solutes and Solvents,Copyright Cengage Learning.All rights reserved,14,In General,One factor that favors a process is an increase in probability of the state when the solute and solvent are mixed.Processes that require large amounts of energy tend not to occur.Overall,remember that“like dissolves like”.,Copyright Cengage Learning.All rights reserved,15,Structure Effects:Polarity Pressure Effects:Henrys law Temperature Effects:Affecting aqueous solutions,Copyright Cengage Learning.All rights reserved,16,Structure Effects,Hydrophobic(water fearing)Non-polar substances Hydrophilic(water loving)Polar substances,Copyright Cengage Learning.All rights reserved,17,Pressure Effects,Little effect on solubility of solids or liquidsHenrys law:C=kPC=concentration of dissolved gask=constantP=partial pressure of gas solute above the solutionAmount of gas dissolved in a solution is directly proportional to the pressure of the gas above the solution.,Copyright Cengage Learning.All rights reserved,18,A Gaseous Solute,Copyright Cengage Learning.All rights reserved,19,Temperature Effects(for Aqueous Solutions),Although the solubility of most solids in water increases with temperature,the solubilities of some substances decrease with increasing temperature.Predicting temperature dependence of solubility is very difficult.Solubility of a gas in solvent typically decreases with increasing temperature.,Copyright Cengage Learning.All rights reserved,20,The Solubilities of Several Solids as a Function of Temperature,Copyright Cengage Learning.All rights reserved,21,The Solubilities of Several Gases in Water,Copyright Cengage Learning.All rights reserved,22,An Aqueous Solution and Pure Water in a Closed Environment,Copyright Cengage Learning.All rights reserved,23,Liquid/Vapor Equilibrium,Copyright Cengage Learning.All rights reserved,24,Vapor Pressure Lowering:Addition of a Solute,Copyright Cengage Learning.All rights reserved,25,Vapor Pressures of Solutions,Nonvolatile solute lowers the vapor pressure of a solvent.Raoults Law:Psoln=observed vapor pressure of solution solv=mole fraction of solvent=vapor pressure of pure solvent,Copyright Cengage Learning.All rights reserved,26,A Solution Obeying Raoults Law,Copyright Cengage Learning.All rights reserved,27,Nonideal Solutions,Liquid-liquid solutions where both components are volatile.Modified Raoults Law:Nonideal solutions behave ideally as the mole fractions approach 0 and 1.,Copyright Cengage Learning.All rights reserved,28,Vapor Pressure for a Solution of Two Volatile Liquids,Copyright Cengage Learning.All rights reserved,29,Summary of the Behavior of Various Types of Solutions,Copyright Cengage Learning.All rights reserved,30,For each of the following solutions,would you expect it to be relatively ideal(with respect to Raoults Law),show a positive deviation,or show a negative deviation?Hexane(C6H14)and chloroform(CHCl3)Ethyl alcohol(C2H5OH)and waterHexane(C6H14)and octane(C8H18),Copyright Cengage Learning.All rights reserved,31,CONCEPT CHECK!,Colligative Properties,Depend only on the number,not on the identity,of the solute particles in an ideal solution:Boiling-point elevation Freezing-point depressionOsmotic pressure,Copyright Cengage Learning.All rights reserved,32,Boiling-Point Elevation,Nonvolatile solute elevates the boiling point of the solvent.T=KbmsoluteT=boiling-point elevationKb=molal boiling-point elevation constantmsolute=molality of solute,Copyright Cengage Learning.All rights reserved,33,Boiling Point Elevation:Liquid/Vapor Equilibrium,Copyright Cengage Learning.All rights reserved,34,Boiling Point Elevation:Addition of a Solute,Copyright Cengage Learning.All rights reserved,35,Boiling Point Elevation:Solution/Vapor Equilibrium,Copyright Cengage Learning.All rights reserved,36,Freezing-Point Depression,When a solute is dissolved in a solvent,the freezing point of the solution is lower than that of the pure solvent.T=KfmsoluteT=freezing-point depressionKf=molal freezing-point depression constantmsolute=molality of solute,Copyright Cengage Learning.All rights reserved,37,Freezing Point Depression:Solid/Liquid Equilibrium,Copyright Cengage Learning.All rights reserved,38,Freezing Point Depression:Addition of a Solute,Copyright Cengage Learning.All rights reserved,39,Freezing Point Depression:Solid/Solution Equilibrium,Copyright Cengage Learning.All rights reserved,40,Changes in Boiling Point and Freezing Point of Water,Copyright Cengage Learning.All rights reserved,41,A solution was prepared by dissolving 25.00 g of glucose in 200.0 g water.The molar mass of glucose is 180.16 g/mol.What is the boiling point of the resulting solution(in C)?Glucose is a molecular solid that is present as individual molecules in solution.100.35 C,Copyright Cengage Learning.All rights reserved,42,EXERCISE!,You take 20.0 g of a sucrose(C12H22O11)and NaCl mixture and dissolve it in 1.0 L of water.The freezing point of this solution is found to be-0.426C.Assuming ideal behavior,calculate the mass percent composition of the original mixture,and the mole fraction of sucrose in the original mixture.72.8%sucrose and 27.2%sodium chloride;mole fraction of the sucrose is 0.313,Copyright Cengage Learning.All rights reserved,43,EXERCISE!,A plant cell has a natural concentration of 0.25 m.You immerse it in an aqueous solution with a freezing point of 0.246C.Will the cell explode,shrivel,or do nothing?,Copyright Cengage Learning.All rights reserved,44,EXERCISE!,Osmosis flow of solvent into the solution through a semipermeable membrane.=MRT=osmotic pressure(atm)M=molarity of the solutionR=gas law constantT=temperature(Kelvin),Copyright Cengage Learning.All rights reserved,45,Copyright Cengage Learning.All rights reserved,46,Osmosis,Copyright Cengage Learning.All rights reserved,47,Copyright Cengage Learning.All rights reserved,48,When 33.4 mg of a compound is dissolved in 10.0 mL of water at 25C,the solution has an osmotic pressure of 558 torr.Calculate the molar mass of this compound.111 g/mol,Copyright Cengage Learning.All rights reserved,49,EXERCISE!,vant Hoff Factor,i,The relationship between the moles of solute dissolved and the moles of particles in solution is usually expressed as:,Copyright Cengage Learning.All rights reserved,50,Ion Pairing,At a given instant a small percentage of the sodium and chloride ions are paired and thus count as a single particle.,Copyright Cengage Learning.All rights reserved,51,Examples,The expected value for i can be determined for a salt by noting the number of ions per formula unit(assuming complete dissociation and that ion pairing does not occur).NaCli=2KNO3i=2Na3PO4i=4,Copyright Cengage Learning.All rights reserved,52,Ion Pairing,Ion pairing is most important in concentrated solutions.As the solution becomes more dilute,the ions are farther apart and less ion pairing occurs.Ion pairing occurs to some extent in all electrolyte solutions.Ion pairing is most important for highly charged ions.,Copyright Cengage Learning.All rights reserved,53,Modified Equations,Copyright Cengage Learning.All rights reserved,54,A suspension of tiny particles in some medium.Tyndall effect scattering of light by particles.Suspended particles are single large molecules or aggregates of molecules or ions ranging in size from 1 to 1000 nm.,Copyright Cengage Learning.All rights reserved,55,Types of Colloids,Copyright Cengage Learning.All rights reserved,56,Coagulation,Destruction of a colloid.Usually accomplished either by heating or by adding an electrolyte.,Copyright Cengage Learning.All rights reserved,57,