摘要
为获得液体内压和摩尔定容热容的准确数据 ,以热力学状态方程和一个液体的 p-V-T方程为基础 ,提出了液体内压的计算方法以及如何由液体的摩尔定压热容推算摩尔定容热容。以包括极性液体、非极性液体和缔合液体的 13种液体为例 ,计算了它们在 2 5℃及 10 1.3 2 5 k Pa时的内压和摩尔定容热容。结果表明 :液体的内压达到 10 0 MPa数量级 ,从而导致液体摩尔定容热容与摩尔定压热容存在很大差异。若以摩尔定压热容的值代替摩尔定容热容 ,在上述 13种液体中的误差为 17%～ 5 6%范围以内。因此得出结论
The thermodynamic equation of state and a p V T equation for liquids were used to develop improved methods for calculating the internal pressure and the molar heat capacity at constant volume of liquids. Internal pressure and molar heat capacity at constant volume were calculated for 13 kinds of liquids at 25 ℃ and 101.325 kPa including polar liquids, non polar liquids and associative liquids. The calculated molar heat capacity at constant volume is shown to be much different than that at constant pressure. Replacing the liquid molar heat capacity at constant volume by its molar heat capacity at constant pressure causes a relative error from 17% to 56%. The results show that the molar heat capacity at constant volume should not be replaced by that at constant pressure for liquids. The large internal pressure of liquids, of the order of 100 MPa, causes the considerable difference between the two molar heat capacities.
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2000年第6期4-5,32,共3页
Journal of Tsinghua University(Science and Technology)
关键词
摩尔定容热容
摩尔定压热容
内压
液体
equation of state
molar heat capacity at constant volume
molar heat capacity at constant pressure
internal pressure
