van't Hoff方程及相关问题的讨论  

Discussion on van't Hoff equation and related problems

作　　者：任聚杰[1] 

机构地区：[1]河北科技大学理学院,河北石家庄050018

出　　处：《河北工业科技》2018年第1期18-23,共6页Hebei Journal of Industrial Science and Technology

基　　金：河北省高等教育教学改革研究项目(2012GJJG073);河北科技大学教育教学改革研究项目

摘　　要：van’t Hoff方程是描述化学平衡常数与温度之间关系的方程,且有"化学反应等压方程"和"化学反应等容方程"之说。目前教材对于这些方程的推导不严格,甚至不正确,对于"等压"和"等容"的含义也没有解释,造成了该方程使用上存在困难,出现许多错误的结论,使得在推导活化能与反应热关系时出现混乱。针对此问题,从化学势是状态函数入手,证明了摩尔反应吉布斯函数也是状态函数,并以此为基础,利用严谨的数学和热力学概念,推出了van’t Hoff方程。结果表明,van’t Hoff方程的2种形式,即所谓的"化学反应等压方程"和"化学反应等容方程",其使用条件与等压和等容无关,只是一种习惯叫法而已。在此基础上,严格导出了理想气体化学反应的Arrhenius活化能和恒压反应热及恒容反应热之间的关系。研究明确了任意反应和理想气体反应van’Hoff方程的形式和使用条件,对人们正确认识和利用热力学领域理想气体反应活化能和反应热的关系打下了基础。van't Hoff equation is the equation describing the relationship between chemical equilibrium constant and temperature,and there is the equation so-called " chemical reaction isobaric equation" and " chemical reaction isochoric equation". In the current textbooks,the derivation of these equations is not strict,even incorrect,and there is no explanation for the meaning of " equal pressure" and " equal capacity". This makes difficulties in the use of the equation,resulting in many wrong conclusions,and leads to confusion in the derivation of the relationship between activation energy and reaction heat. Starting from the state function of the chemical potential,it is proved that the molar reaction Gibbs function is also a state function. Based on this,the van't Hoff equation is introduced using rigorous mathematical and thermodynamic concept. It is also proved that the two forms of the van't Hoff equation,the so-called " chemical reaction isobaric equations" and " chemical isometric equations",are not related to isobaric and isometric. It's just a habit name.On this basis,the relationship between Arrhenius activation energy and constant pressure reaction heat and constant volume reaction heat of the ideal gas chemical reaction is strictly derived. This study clarifies the van't Hoff equation and the use conditions of the equation of arbitrary and perfect gas reactions,and lays the foundation for the correct realization and application of the relationship between perfect gas reaction activation energy and the reaction heat in the thermodynamics field.

关 键 词：化学热力学 van’t Hoff方程 恒压反应 恒容反应 理想气体 活化能 

分 类 号：O642[理学—物理化学]