Joule-Thomson coefficient OT J-T The isenthalpic j-T coefficient 是系统的强度性质。因为节流过程的dp<0 所以当 -r>0经节流膨胀后,气体温度降低。 -r<0经节流膨胀后,气体温度升高。 -r=0经节流膨胀后,气体温度不变。 4上一内容下一内容令回主目录 返回 2021/2/21
上一内容 下一内容 回主目录 返回 2021/2/21 Joule-Thomson coefficient： J-T >0 经节流膨胀后，气体温度降低。 J-T ( )H T p = - The isenthalpic J-T coefficient J-T 是系统的强度性质。因为节流过程的 , 所以当： J-T d 0 p J-T <0 经节流膨胀后，气体温度升高。 J-T =0 经节流膨胀后，气体温度不变
Extent of reaction bD+vE+…→VF+v(G+ t=0,5=0 D,0 E,0 G.0 t=t, s=5 n E 20世纪初比利时的 Dekonder引进反应进度E的定义为: d B B.0 ds= 2单位:mo B is the stoichiometric coefficient of component B negative -reactants and positive -products 4上一内容下一内容令回主目录 返回 2021/2/21
上一内容 下一内容 回主目录 返回 2021/2/21 Extent of reaction 20世纪初比利时的Dekonder引进反应进度的定义为： B B,0 B n n − = B B d d n = D E F G D E F G + +→ + + t = t, = D n E n F n G n t = 0, = 0 nD,0 nE,0 nF,0 nG,0 单位：mol is the stoichiometric coefficient of component B, negative - reactants and positive - products
extent of reaction 引入反应进度的优点: 在反应进行到任意时刻,可以用任一反应物 或生成物来表示反应进行的程度,所得的值都是 相同的,即: dn dn de= E F G E E F 4上一内容下一内容◇回主目录 返回 2021/2/21
上一内容 下一内容 回主目录 返回 2021/2/21 extent of reaction 引入反应进度的优点： 在反应进行到任意时刻，可以用任一反应物 或生成物来表示反应进行的程度，所得的值都是 相同的，即： D E F G D E F G d d d d d n n n n = = = = = d= g dn f dn e dn d dnD E F G = = − = −
The reaction enthalpy If the trans fer of heat occurs at constant volume and if no other forms of work are permitted (△Uy=Q For a specified change of state AU is independent of how the change is brought about, therefore the subscript v can be dropped from U: AU=Qv The significance of this equation is that if we measure the heat transferred at constant volume we can identify it with the change in a thermodynamic state function 4上一内容下一内容令回主目录 返回 2021/2/21
上一内容 下一内容 回主目录 返回 2021/2/21 If the transfer of heat occurs at constant volume, and if no other forms of work are permitted, (△U)v = Qv . For a specified change of state △U is independent of how the change is brought about,therefore the subscript v can be dropped from U: △U = Qv . The significance of this equation is that if we measure the heat transferred at constant volume we can identify it with the change in a thermodynamic state function. The reaction enthalpy
The analogous result for changes occurring at constant pressure AH=QP. When there is no work other than pv-work The relation between△Hand△U The enthalpy of a substance differs from its thermodynamic energy by an amount pv It follows that AH=AU +pVi(products)-[pV](reactants) For reactions involving only solids and liquids △H≈△U 4上一内容下一内容◇回主目录 返回 2021/2/21
上一内容 下一内容 回主目录 返回 2021/2/21 The analogous result for changes occurring at constant pressure. △H = Qp . When there is no work other than PV-work. The relation between △H and △U . The enthalpy of a substance differs from its thermodynamic energy by an amount pV. It follows that △H = △U +[pV](products)-[pV](reactants) For reactions involving only solids and liquids: △H △U