物化上双语课件35

1、 ：华东理工大学物理化学教研室Physical ChemistryYing Hu(Fifth edition)Bilingual Program ：华东理工大学物理化学教研室Bilingual ProgramThermodynamics of ponent Systems, Fugacity and ActivityChapter 3 ：华东理工大学物理化学教研室Bilingual Program. Fugacity, Activity and Mixing PropertiesII. Fugacity, Activity and Mixing Properties3.6 Chemical P

2、otential and Fugacity3.7 Fugacity and Fugacity Factor 3.8 Raoults Law and Henrys Law3.9 Ideal Mixture and Ideal Dilute Solution3.10 Chemical Potential and Activity (1)3.11 Activity and Activity Factor3.12 Chemical Potential and Activity (2)3.13 Mixing Properties and Excess Functions3.6 Chemical Pote

3、ntial and FugacityPureMixturePureMixtureThermodynamic standard state of gas phase as the reference state,Real SubstanceIdeal Gases3.6 Chemical Potential and FugacityFugacitydefPure substanceMixtureFugacity FactordefFugacity Factor3.7 Fugacity and Fugacity FactorPure substanceMixture1, Strong repulsi

4、ve tendency II. Fugacity, Activity and Mixing Properties3.6 Chemical Potential and Fugacity3.7 Fugacity and Fugacity Factor 3.8 Raoults Law and Henrys Law3.9 Ideal Mixture and Ideal Dilute Solution3.10 Chemical Potential and Activity (1)3.11 Activity and Activity Factor3.12 Chemical Potential and Ac

5、tivity (2)3.13 Mixing Properties and Excess FunctionsRaoults LawHenrys lawIdeal solutions Ideal-dilute solutionsSolvent observes Raoults lawSolute observes Henrys lawFor both solvent and solute, observe Raoults Law3.8 Raoults Law and Henrys LawII. Fugacity, Activity and Mixing Properties3.6 Chemical

6、 Potential and Fugacity3.7 Fugacity and Fugacity Factor 3.8 Raoults Law and Henrys Law3.9 Ideal Mixture and Ideal Dilute Solution3.10 Chemical Potential and Activity (1)3.11 Activity and Activity Factor3.12 Chemical Potential and Activity (2)3.13 Mixing Properties and Excess FunctionsLiquid: A+BGas:

7、 A+BEquilibrium3.10 Chemical Potential and Activity (1)How can we calculate the chemical potential of a real solution?For real gases mixture, FugacityGaseous reference stateFor a solution, what is the reference state? what is the characteristic property of the component? Selection I Select the liqui

8、d or solid pure component at the system temperature and pressure as the reference state. 3.10 Chemical Potential and Activity (1)Liquid and Solid Ideal Mixtures(a) In vapor-liquid (V-L) or vapor-solid (V-S) equilibrium(b) Considering of the component i in the gas phase, Selection I Select the liquid

9、 or solid pure component at the system temperature and pressure as the reference state. 3.10 Chemical Potential and Activity (1)Liquid and Solid Ideal Mixturesis the chemical potential of the pure liquid or pure solid i at the temperature T and the reference state of the selection I.3.10 Chemical Po

10、tential and Activity (1) of the reference state has reflected the important characteristics of the component i in the ideal mixture, the difference between and is expressed simply by the composition xi, increases linearly with the logarithm of xi. Selection I Select the liquid or solid pure componen

11、t at the system temperature and pressure as the reference state. Real MixturesTo obtain a concise and unique expression3.10 Chemical Potential and Activity (1)is the chemical potential of the pure liquid or pure solid i at the temperature T and the reference state of the selection I.ai, Activity, Th

12、e difference between the properties of the component in a real solution and that at the reference state, it is a state function and an intensive property Activity (selection I) 2. Expression for Chemical Potentials of Components in Liquid and Solid Real Mixtures, Activity 3.10 Chemical Potential and

13、 Activity (1)For ideal mixtures：ai = xi；Activity Factor (selection I)DefinitiondefDefinitiondefActivity factor represents the departure from the ideal mixture.When a liquid or solid mixture is in equilibrium with its vapor, if the gas phase can be regarded as an ideal gas,3.10 Chemical Potential and

14、 Activity (1)Activity and Vapor-Liquid (Solid) EquilibriumThe activity ai is a correction to xi when applying the Raoults law to real mixtures and can be regarded as an effective mole fraction.Positive deviationNegative deviation3.10 Chemical Potential and Activity (1)Physical Meaning of the Activit

15、y3. Relation between Activity and Fugacity When the pressure is very high, the gas phase can not be regarded as ideal gasThe activity is the ratio of the fugacity of the state studied to that of the reference state. 3.10 Chemical Potential and Activity (1)II. Fugacity, Activity and Mixing Properties

16、3.6 Chemical Potential and Fugacity3.7 Fugacity and Fugacity Factor 3.8 Raoults Law and Henrys Law3.9 Ideal Mixture and Ideal Dilute Solution3.10 Chemical Potential and Activity (1)3.11 Activity and Activity Factor3.12 Chemical Potential and Activity (2)3.13 Mixing Properties and Excess Functions1.

17、Experimental MethodDetermining the total pressure and the composition of the vapor at a certain temperature for the liquid mixture with a certain composition, i.e., the pTxy relation, ai and i can be calculated by the above equation. 3.11 Activity and Activity FactorIf only the solvent is volatile,

18、and the solute is non-volatile, the method can only be used to obtain i for the solvent. ExampleThe following data were obtained for the CS2(A)-CH3COCH3(B) mixture at 29.2: xB=0.540, p= 69.79kPa, yB=0.400. Calculate ai and i. It is known that: Solution(I) is an example of a positive deviation and (I

19、I) is that of a negative deviation, both deviations are with respect to the ideal mixture. 3.11 Activity and Activity FactorActivity-Factor DiagramCS2(A)-CH3COCH3(B)CHCl3(A)- CH3COCH3(B)(I)(II)2. Activity-Factor Correlation Equation van Laar Margules NRTL UNIQUACWilsonSolubility parameter equationGr

20、oup-contribution methodsASOGUNIFAC3.11 Activity and Activity FactorII. Fugacity, Activity and Mixing Properties3.6 Chemical Potential and Fugacity3.7 Fugacity and Fugacity Factor 3.8 Raoults Law and Henrys Law3.9 Ideal Mixture and Ideal Dilute Solution3.10 Chemical Potential and Activity (1)3.11 Act

21、ivity and Activity Factor3.12 Chemical Potential and Activity (2)3.13 Mixing Properties and Excess Functions1. Selection II For the solute B, select the liquid or solid pseudo pure component B with the characteristics of an ideal dilute solution at the system temperature and pressure as the referenc

22、e state.(1) The solvent A observes the Raoults law3.12 Chemical Potential and Activity (2) the chemical potential of the solute B at the reference state of the selection IILiquid and Solid Ideal Dilute Solutions1. Selection II For the solute B, select the liquid or solid pseudo pure component B with

23、 the characteristics of an ideal dilute solution at the system temperature and pressure as the reference state.(2) the solute B observes the Henrys law3.12 Chemical Potential and Activity (2)Liquid and Solid Ideal Dilute Solutions2. Expressions for Chemical Potentials of Solvent and Solute in Real S

24、olutions, Activity3.12 Chemical Potential and Activity (2)Solvent AThe reference stateSelection ISolute BSelection II The activity factors represent the departure from the ideal dilute solution. They are a measure of the non-ideality.Ideal dilute solutions3.12 Chemical Potential and Activity (2)Defi

25、nition of the Activity of the Solute (selection II)Activity Factor (selection II)When a liquid or solid solution is in equilibrium with its vapor, if the gas phase can be regarded as ideal gas,Solvent ASolute B3.12 Chemical Potential and Activity (2)Activity and Vapor-Liquid (Solid) EquilibriumPhysi

26、cal Meaning of the ActivityThe activities aA and ax,B are corrections to xA and xB when applying the Raoults law and the Henrys law to the solvent and the solute of real solutions, respectively, and can be regarded as effective mole fractions. When xA1, xB0, the solution approaches an infinite dilut

27、e solution, corresponding to an ideal dilute solution, 3.12 Chemical Potential and Activity (2)WhenActivity and Activity Factor by Experimental DataIf the vapor can not be considered as ideal gas, the vapor pressure or the partial pressure in the above equations should be replaced by the fugacity. 3

28、.12 Chemical Potential and Activity (2)ExampleFor a solution composed of H2O(A) and CH3COCH3(B) at 25, experiments gave: xB = 0.1791, p = 21.30 kPa, yB = 0.8782. It is known thatSolutionHenrys lawSelectionReference stateIdeal dilute solutionChemical potential of the reference stateA real solutionDef

29、inition of Activity and the activity factor3.12 Chemical Potential and Activity (2)IIIIV5. Conversion among Activity Factors of Various Selections Liquid-liquid mixtures, each component can adopt the selection I. also can be distinguished as the solvents, adopt the selection I, and the solutes, adop

30、t the selection II, III and IV, respectively. Gas-liquid mixtures, the solvents, adopt the selection I, and the solutes, adopt the selection II, III and IV, respectively. Solid-liquid mixtures, the solvents, adopt the selection I, and the solutes, adopt the selection II, III and IV, respectively. in

31、 chemical engineering, electro chemistry and bio chemistry mostly adopt the selection III and IV, respectively. 3.12 Chemical Potential and Activity (2)The conversion among activity factors of various selections can then be derived asThe chemical potential is irrelevant to the selections, so is the

32、vapor pressure in equilibrium.For pure A and B binary mixture, the vapour pressure of B, pB, change with xB can be expressed as Calculate:(1) What is the vapour pressure of pure B?(2) Adopting Selection I, when xB = 0.5, what are rB and aB ?(3) What is KHx,B ?(4) Adopting Selection II, when xB = 0.5, what are rx,B and ax,B? (5) This solution has a positive deviation or a negative deviation?Examples (1) What is the vapour pressure of pure B?