应用胞腔理论计算纯物质的汽化热

1引言胞腔模型或称自由体积模型早在本世纪30年代就已经提出［’－‘］，但由于该模型的重要参数，即自由体积一直无法予以确定，以至于就无法用该模型来计算物质的一系列性质、作者曾于1985年利用胞腔型状态方程导出两个物质特性参数一内压因子和构形因子问，本文根据上述状态方程和两个特性参数导出了计算物质的自由体积公式。从此即可应用自由体积参数计算物质的热力学性质。本文是介绍应用自由体积参数计算纯物质的汽化热的方法。2自由体积模型的液体理论和自由体积的计算自由体积理论最早由Lennard－Jones和Devon－shire用来将液体的…

CALCULATION OF VAPORIZATION ENTHALPIES OF PURE COMPOUNDS BY THE CELL THEORY OF LIQUIDS

On the basis of the cell theory of liquids and the law of corresponding states several char-acteristic parameters of substances-configuration factor, internal pressure factor and polarityfactor had been presented. Thus, the correlation of free volume variable with configurationfactor and internal pressure factor was deduced from Hirschfelder equation of state of liquid.In addition, the equation for calculating the latent heats of vaporization of pure substancesfrom free volume variables is also derived by statistical thermodynamic method in this paper.Then, the proposed equation is applied to estimate the vaporization enthalpy data of 50 puresubstances at normal boiling point. And all results show that the proposed equation is fairlyfitted to experimental data, giving an average absolute deviation of only 1.16%. The greatestadvantage of this equation is simple and convenient in calculating. The above results alsoshow that the theory of cell model is valid.