MgCl_2·nH_2O的溶解与水合热化学研究  

Thermo-chemical Study of Dissolution and Hydration of MgCl_2·nH_2O

作　　者：张军[1] 赵萍[1] 

机构地区：[1]河南科技大学化工与制药学院,河南洛阳471003

出　　处：《河南科技大学学报（自然科学版）》2005年第2期93-97,i007,共6页Journal of Henan University of Science And Technology:Natural Science

基　　金：国家自然科学基金资助项目(20171022);河南科技大学重大预研基金资助项目(2004ZD005);河南科技大学人才科学研究基金资助项目(04011)

摘　　要：利用精密量热计测定了氯化镁及其水合物(MgCl2、MgCl2·2H2O、MgCl2·4H2O、MgCl2·6H2O)晶体在298.15K温度下溶于水的积分溶解热。利用Pitzer电解质溶液理论模型,计算了溶质的相对表观摩尔焓,从而直接获得了它们的标准摩尔溶解焓分别为(-155.86±0.17)、(-79.45±0.17)、(-41.78±0.18)和(-14.58±0.16)kJ·mol-1。氯化镁2、4、6水合物晶体的标准摩尔生成焓分别为-1289.39、-1898.72和-2497.58kJ·mol-1;摩尔水合焓则依次为-76.41、-114.08和-141.28kJ·mol-1。并依据Born-Haber循环法得到它们的晶格能依次为-2490.36、-3158.37、-3772.70和-4376.56kJ·mol-1。The integral dissolution heats of MgCl_2,MgCl_2·2H_2O,MgCl_2·4H_2O,MgCl_2·6H_2O in water at 298.15 K were determined by using precision calorimeter.The relative apparent molar enthalpies of MgCl_2 and its hydrates were calculated by utilizing Pitzers' electrolytic solution model.The mean integral dissolution enthalpies for MgCl_2 and its hydrates (MgCl_2·2H_2O,MgCl_2·4H_2O,MgCl_2·6H_2O) are-154.94,-78.56,-40.78 and-13.14 kJ·mol^-1 ,respectively.The standard molar hydration enthalpies and formation enthalpies for the three hydrates were also accurately obtained with the values of (-76.41,-114.08 and-141.28 kJ·mol^-1 ) and (-1289.39,-1898.72 and-2497.58 kJ·mol^-1 ) respectively.According to Born-Haber circulation method,the lattice energy for them was estimated.

关 键 词：MGCL2 化学研究 水合热 标准摩尔生成焓 电解质溶液 表观摩尔焓 摩尔溶解焓 理论模型 水合物 氯化镁 量热计 溶解热 15K 水合焓 晶格能 循环法 晶体 积分 溶质 

分 类 号：O6-1[理学—化学] TQ325.12[化学工程—合成树脂塑料工业]