硼砂热力学性质的研究

Thermodynamic Properties of Borax Decahydrted

中文关键词:  硼砂  低温热容  热力学函数

英文关键词:Borax decahydrate  Low heat capacities  Thermodynamic function

中文摘要:

      通过精密自动绝热量热仪测定了硼砂(Na2B4O7.10H2O)在78~345 K的热容。实验结果表明,硼砂在330~336 K温度区间有一个脱水-溶解峰,密闭加热条件下其熔点为334.38 K。用最小二乘法将脱水前的实验摩尔热容对折合温度进行拟合,得到了此温区的热容随温度变化的多项式方程,Cp,m=447.782 77+229.452 55X-49.129 89X2+21.504 25X3十24.551 12X4。用热容多项式方程进行数值积分获得了该物质在80~325 K温区每隔5 K的热力学函数值。

英文摘要:

      The heat capacities of borax decahydrate(Na2B4O7· 10H2O)was measured by a precision automated adiabatic calorimeter in the temperature range from 78 to 345 K.The experimental results indicate that in the 330 ~ 336K temperature range there is a dehydration-dissolution peak.Its melting temperature is 334.38 K when heated in the closed space. Polynomial equation of the heat capacities as a function of the temperature was fitted by the least square method before dehydration.The function is as following,Cp,m= 44...