a better method OZ OZ dz=w dx+o) By dividing by at const.X OZ OZ、Ow By dividing by“dx”" at const.y; OZ aZ OZ、Ow +( OX 4上一内容下一内容◇回主目录 返回 2021/2/22
上一内容 下一内容 回主目录 返回 2021/2/22 A better method dw w Z dx x Z dZ w x ( ) ( ) + = By dividing by “dy” at const. x; x x x y w w Z y Z ( ) ( ) ( ) = By dividing by “dx” at const. y; y w x y x w w Z x Z x Z ( ) ( ) ( ) ( ) + =
For a pure substance For a homogeneous system molar volume m, B 12, B molar thermodynamIc energy U m, B 4上一内容下一内容◇回主目录 返回 2021/2/22
上一内容 下一内容 回主目录 返回 2021/2/22 B * m,B n V V = molar volume B * m,B n U U = molar thermodynamic energy For a pure substance For a homogeneous system:
The thermodynamic functions molar enthalpy H._H m molar entropy B molar Helmholz free energy molar Gibbs free energy B G m B B 4上一内容下一内容令回主目录 返回 2021/2/22
上一内容 下一内容 回主目录 返回 2021/2/22 The thermodynamic functions B * m, B n H molar enthalpy H = B * m,B n S molar entropy S = B * m, B n A A = molar Helmholz free energy B * m, B n G G = molar Gibbs free energy
Open systems and changes of composition The formulation presented so far is obviously incomplete because it has been tacit assumed that composition remains constant Furthermore, the expression dg= vap-SaT suggests that g is a function of only P and t, and that when these are held constant dg=o: this conflicts with the result derived on p. 149 that at constant p and t we have dG= Sw 4上一内容下一内容◇回主目录 返回 2021/2/22
上一内容 下一内容 回主目录 返回 2021/2/22 Open systems and changes of composition The formulation presented so far is obviously incomplete because it has been tacitly assumed that composition remains constant. Furthermore, the expression dG = VdP – SdT suggests that G is a function of only P and T, and that when these are held constant dG = 0: this conflicts with the result derived on p. 149 that at constant P and T we have dG = Wmax
The two points are connected, for we shall now see that taking composition variation into account allows us to identify a source of non-pV work Now we define partial molar quantity and describe how any thermodynamic quantity depends on the composition of the system Almost everything we do will be confined to systems with only two components: these are binary mixtures 4上一内容下一内容令回主目录 返回 2021/2/22
上一内容 下一内容 回主目录 返回 2021/2/22 The two points are connected, for we shall now see that taking composition variation into account allows us to identify a source of non-pV work. Now we define partial molar quantity and describe how any thermodynamic quantity depends on the composition of the system. Almost everything we do will be confined to systems with only two components: these are binary mixtures