摘要
研究了液体的蒸发热与内压间的关系,发现液体的蒸发熵与软球压缩因子P_iV/RT之间存在着很好的比例关系。据此,建立了一个能够计算不同温度下液体蒸发热的公式:△H_v=RTV^2/n(V^2-AV+B)。由22种液体在正常沸点下的蒸发热计算结果表明,计算值与实验值的平均相对误差为±1%。本文还修正了Fronk关系式,认为在小的体积变化范围内,液体的能量与摩尔体积间的关系应为U=U_■+RT-a′/V^R由此也可得到液体的内压为P_i=na′/V^(n+1)=a/V^m,但是,式中的n=P_iV/ΔH_v,而不是P_iV与蒸发能ΔU_v之比。
The relationship between vaporization heat and internal pressure has been dealt with for liquids. Based on the proportional relation which has been found between vaporization enthalpy and Soft sphere compressibility factor P_iV/RT for liquids, an equation to calculate the vaporization heat at various temperatures was established:■The mean relative discrepancy between the calculated and the experimental value is±1% at normal boiling points for 22 liquids, Frank's formula has been modified in small range of volume change, the relation between energy and molar volume of liquids should be considered as ■ and therefore internal pressure for liquids can be obtained as follows ■ but in this equation n equals to P_iV/ΔH, rather than the ratio of P_iV to vaporization energyΔU_v.
关键词
液体
蒸发热
内压力
溶液
热力学
liquid
internal pressure
thermodynamics: solution theory
vaporization heat
