A research of Ven der Waals Equation

• Main Authors: Shen-Yen Chao, 趙慎言
• Other Authors: Wen-Chung Li
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/60569026178263634015

碩士 === 國立臺灣大學 === 物理研究所 === 101 === This thesis aims to make a clear and systematic explaination of the historical origins of van der waals equation, explore the connotation of van der waals equation with algebraic methods and related thermodynamic theory. We compared the experimental and theoretical values of the critical temperature of the several gas,including water vapor, nitrogen,carbon dioxide,and examined the application of van der Waals equation to phase transition phenomena. When the method of Maxwell''s Construction is applied to the Van der Waals isotherm, the following conclusions are obtained: (1) The theoretical values of the vapor pressure of the different gas molecules obtained by the van der Waals equation is not completely in accordance with the experimental values, there is a positive deviation of the saturated vapor pressure of water vapor, and carbon dioxide value shows a negative deviation. The reason is the structure of the various gas molecules are quite different, so the intermolecular potential varies drastically. (2) When the temperature is only slightly lower than the critical temperature, the theoretical value can still fit the experimental data. Well, however, for still lower temperatures, the difference between the two is significant. When we switch to an R-K equation and do the same type of comparison, the difference between the theoretical value and experimental data is reduced.