物理化学英文课件：chapter10-2 Nonideal Solutions

1、Chapter 10Nonideal SolutionsPhysical ChemistrySimple SolutionModels for Nonelectrolyte Activity CoefficientsNonideal SolutionsW depends on T and P but not on the mole fractions.let z be the number of nearest neighbors of each molecule in the array. The intermolecular-interaction energy is approximat

2、ed as the sum of nearest-neighbor interactions. (10.31)If BB, CC, and BC are the interaction energies for adjacent B-B, C-C, and B-C pairs, respectively. The energy of mixingPhysical ChemistryNonideal SolutionswhereFor two liquids B and C whose molecules have similar sizes and shapes,Models for None

3、lectrolyte Activity CoefficientsPhysical ChemistryNonideal Solutionssimple solution model(10.32)(Problem 10.4)Models for Nonelectrolyte Activity CoefficientsRedlich-Kister equation (Margules equation)Physical Chemistry(10.31)Nonideal Solutionssimple solution model(10.32)Models for Nonelectrolyte Act

4、ivity CoefficientsRedlich-Kister equation (Margules equation)Physical ChemistrySolutions of ElectrolytesNonideal SolutionsNon-electrolyte solutionsThe solute is not present as ionsElectrolyte solutionsThe solute is ionized and the ions generally interact strongly with each other.(10.33)Numbers of io

5、ns in the chemical formula (integers)Charges of ions in the chemical formula2:1 electrolyte1:2 electrolyte2:2 electrolytePhysical ChemistryChemical Potentials in Electrolyte SolutionsNonideal SolutionsSince + and - are not measurable, define i (the chemical potentials of the electrolyte as a whole)

6、in solution(10.33)(10.35)(10.34)Physical ChemistryChemical Potentials in Electrolyte SolutionsNonideal Solutions(10.35)Similar definition for other partial molar properties of the electrolyte as a whole.(10.36)(10.33)fromPhysical ChemistryChemical Potentials in Electrolyte SolutionsNonideal Solution

7、s(10.37)(10.33)Keep T, P, and nA constant and using(10.36)(10.35)(10.38)*(10.39)On the mole-fraction scale, the chemical potential of solventPhysical ChemistryChemical Potentials in Electrolyte SolutionsNonideal Solutions(10.39)mole-fraction activity coefficientinfinite dilutionOn the molality scale

8、, the chemical potentials of electrolyte(10.40)(10.41)(10.38)*(10.42)Physical ChemistryChemical Potentials in Electrolyte SolutionsNonideal SolutionsMolality-scale mean ionic activity coefficient(10.45)*(10.44)(10.43)*(10.42)(10.46)(10.47)Physical Chemistry(10.41) and (10.43)(10.41)Chemical Potentia

9、ls in Electrolyte SolutionsNonideal Solutions(10.47)(10.48)Stoichiometric molality(10.46)(10.49)(10.45)*(10.50)(10.43)*definePhysical ChemistryChemical Potentials in Electrolyte SolutionsNonideal Solutions(10.49)(10.50)The standard state of i as a whole is taken as the fictitious state with(10.51)(1

10、0.49)(10.46)hasPhysical ChemistryChemical Potentials in Electrolyte SolutionsNonideal Solutions(10.52)Gibbs Energy of an Electrolyte Solution(10.51)givesThe activity ai of electrolyte i as a whole (10.4)(10.37)(10.38)*(10.53)(10.54)(10.55)Gibbs-Duhem Eq.Physical ChemistryThe Debye-Hckel Theory of El

11、ectrolyte SolutionsNonideal SolutionswhereThe Debye-Hckel treatment assumes that the solution is very dilute. (10.60)(10.61)(10.62)*(10.63)Ionic strengthPhysical Chemistrylog of (10.43)The Debye-Hckel Theory of Electrolyte SolutionsNonideal Solutions(10.64) z+The electrolyte neutrality gives(10.64)(

12、10.64) z-+)(10.65)(10.60)(10.63)(10.66)Physical ChemistryThe Debye-Hckel Theory of Electrolyte SolutionsNonideal SolutionsFor very dilute solutions, Im is very small(10.66)(10.67)(10.68)(10.69)very dilute aqueous solution, 25oCvery dilute aqueous solution, 25oCvery dilute solutionPhysical ChemistryT

13、he Debye-Hckel Theory of Electrolyte SolutionsNonideal Solutions(10.69)Debye-Hckel limiting law(10.67)(10.70)dilute aqueous solution, 25oC(10.71)at higher concentrations in H2O at 25oCPhysical ChemistryHomeworkNonideal SolutionsPhysical ChemistryP315-316, Section 10.510.16, 10.18P316, Section 10.610

14、.31, 10.32, 10.33P316, Section 10.810.38, 10.39, 10.40 Ionic AssociationNonideal Solutions(10.72)The equilibrium for ion-pair formation(10.73)If no ion pairs were found, With ion-pair formation, (10.33)(10.74)Physical ChemistryIonic AssociationNonideal Solutions(10.72)Use of the equilibrium conditio

15、n for the ion-pair formation (10.72)(10.75)Same as (10.37) Physical ChemistryNonideal Gas MixturesNonideal SolutionsThe activity of a component of a nonideal gas mixtureThe fugacity fi of a component of any gas mixture (10.94)(10.95)(10.96)(10.95) becomes(10.97)*“effective P”Physical ChemistryNonideal Gas MixturesNonideal Solutionsnonideal gas mixture(10.97)*(6.4)*ideal gas mixture(10.98)The deviation of the fugacity fi of i from the partial pressure Pi in a gas mixture is measured by the fugacity coefficient i of gas i.