对称性与热力学自发变化方向.doc

延 边 大 学 （ 二 〇 一 四 年 五 月 摘 要 本文通过对热力学理论知识和对称性方面的研究分析，得出了分子对称性与热力学自发变化方向之间的相互关系。即体系由对称到不对称的过程中，总是朝着自发变化方向进行。 在文章开始，通过介绍热力学基础知识，了解热力学相关定律、Carnot定理，得出了焓变与反应方向之间的关系。因为焓变作为判据是有局限性的，所以后面又有了用熵变来判断化学变化方向。通过 一些热化学方程式推导出Helmholtz函数和Gibbs函数，根据它们变化值得大小作为变化方向和限度的依据。归纳、整理，得出可以作为判据的有：熵增加原理、Helmholtz函数和Gibbs函数降低原理。研究完了转化方向相关知识，我们还研究了一个新判据——对称性。从对称性的概念、应用领域来详细明了地证明了它在宏观和微观世界的存在价值。 最后，总结得出了热力学自发变化方向和对称性之间的内在联系。从热力学角度上分析，系统总是自发的是由熵低的状态向熵高的状态转变；从对称性角度上分析，系统是由对称度低的状态向对称度高的状态转变，直到系统达到重新平衡。 关键词：对称性；熵增加原理；Helmholtz函数；Gibbs函数；焓变 Abstract Based on analysis of the thermodynamic theory of knowledge and the symmetry, I get the relationship between the molecular symmetry and spontaneous change direction. The system is symmetric to asymmetric process, always move toward the direction of spontaneous change. At the start of article, by introducing the basic knowledge of thermodynamics, by understanding the thermodynamic law, the Carnot theorem, we have got the relation between enthalpy and reaction direction. Because the enthalpy change as a criterion is limited, so there has been used to determine the chemical changes in the direction of the entropy change. Through some thermochemical equation to derive the Helmholtz function and Gibbs function, according to their size and extent change as the direction of change of basis. By the summary, it can be taken as a criterion for the principle of entropy increase,the Helmholtz function and the Gibbs function reduce principle. After the study direction of transformation related knowledge, we also study a new criterion – symmetry. From the concept, the symmetry of the application domain with clearly proved it in the macroscopic and microscopic world the existence value. Finally, summarizes the relationship between spontaneous change direction and symmetry. Thermodynamically, the system always spontaneous is changed from low entropy to high entropy condition; the analysis from the perspective of symmetry,