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The properties of mixtures. 자연과학대학 화학과 박영동 교수. Chapter 6 The properties of mixtures 6.1 The thermodynamic description of mixtures 6.1.1 Partial molar properties 6.1.2 Spontaneous mixing 6.1.3 Ideal solutions 6.1.4 Ideal dilute solutions 6.1.5 Real solutions: activities
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The properties of mixtures 자연과학대학 화학과 박영동 교수
Chapter 6 The properties of mixtures 6.1 The thermodynamic description of mixtures 6.1.1 Partial molar properties 6.1.2 Spontaneous mixing 6.1.3 Ideal solutions 6.1.4 Ideal dilute solutions 6.1.5 Real solutions: activities 6.2 Colligative properties 6.2.6 The modification of boiling and freezing points 6.2.7 Osmosis 6.3 Phase diagrams of mixtures 6.3.8 Mixtures of volatile liquids 6.3.9 Liquid-liquid phase diagrams 6.3.10 Liquid-solid phase diagrams 6.3.11 The Nernst distribution law
At 25°C, the density of a 50 per cent by mass ethanol/water solution is 0.914 g cm-3. Given that the partial molar volume of water in the solution is 17.4 cm3 mol-1, what is the partial molar volume of the ethanol?
Chap. 5 Pressure dependence of G G = H – TS dG = dH – TdS – SdT = Vdp - SdT = V For liquid or solid, ΔG = VΔp For vapor, ΔG = ∫Vdp = nRT∫(1/p)dp =nRTln(pf/pi) ΔGm=RT ln(pf/pi) ch05f01
The Gibbs energy of mixing of two perfect gases of two liquids that form an ideal solution.
Chap. 4 The entropy change with isothermal expansion ch04f04
The entropyof mixing of two perfect gases of two liquids that form an ideal solution.
Raoult's law: pA=xApA*
Raoult’s law The partial vapour pressure of a substance in a liquid mixture is proportional to its mole fraction in the mixture and its vapour pressure when pure: Figure 6.6 The partial vapour pressures of the two components of an ideal binary mixture are proportional to the mole fractions of the components in the liquid. The total pressure of the vapour is the sum of the two partial vapour pressures.
certain composition makes the solution more volatile CS2 is more volatile
Raoult’slaw: for Ideal solution, esp. for solvent The partial vapour pressure of a substance in a liquid mixture is proportional to its mole fraction in the mixture and its vapour pressure when pure: Figure 6.6 The partial vapour pressures of the two components of an ideal binary mixture are proportional to the mole fractions of the components in the liquid. The total pressure of the vapour is the sum of the two partial vapour pressures.
chemical potential of a solvent A present in solution at a mole fraction xA is
At equilibrium, chemical potential of any given component is same everywhere.
The experimental partial vapour pressures of a mixture of trichloromethane, CHCl3 (C), and propanone, CH3COCH3 (acetone, A),
The chemical potential of the solute has its standard value when the molar concentration of the solute is 1 mol dm−3 (that is, ).
G = H – TS dG = dH – TdS – SdT = Vdp – SdT dμ = Vmdp– SmdT μs= μ*– Sm(s) dT μl= μ*– Sm(l) dT + RT lnxA {Sm(l) - Sm(s) }ΔT = RTlnxA μ* • -Sm(s)ΔT RTlnxA • -Sm(l)ΔT μ*+ RTlnxA
μg= μ*– Sm(g) dT μl= μ*– Sm(l) dT + RT lnxA {Sm(l) - Sm(g) }ΔT = RTlnxA μ* {Sm(l) - Sm(g) }ΔT = RTlnxA • Sm(g)ΔT μ*+ RTlnxA • Sm(l)ΔT
μA(xA=1, p) = μA(xA, p+Π) μA(xA, p+Π) μA(xA=1, p)
Understanding fractional distillation • pA=xApA*=apA* • pB=xBpB* = (1-a)pB* • a'= pA/(pA+pB)= apA*/(apA*+(1-a)pB*) • = apA*/(pB* + a(pA*-pB*))
Liquid-Vapor Composition and fractional distillation a'= yA= mole fraction in vapor • a'= pA/(pA+pB) • = apA*/(apA*+(1-a)pB*) • = apA*/(pB* + a(pA*-pB*)) • a'= aX/(1+a(X-1)) • where X = (pA* /pB*) a= xA= mole fraction in liquid
B: lessvolatile substance 나오는것은 A, 남는 것은 B A: morevolatile substance
low-boiling(positive) azeotrope repeated distillation can never produce a distillate that is richer in constituent X than the azeotrope 끓어나오는 것은 Azeotrope, 남는것은 A나 B
공비(共沸) 혼합물 high-boiling(negative) azeotrope 끓어나오는 것은 A나 B이지만, 남은것은 Azeotrope