硼酸盐水溶液热力学研究——4.离子对[CaB(OH)_4]^+标准缔合常数的确定  

The Thermodynamics of Aqueous Borate Solutions——4. The Standard Association Constant of Ion Pair [CaB(OH)_4]^+

作　　者：孙柏[1] 杨家振[2] 宋彭生[1] 邓敏[2] 高岩岩 

机构地区：[1]中国科学院青海盐湖研究所,西宁810008 [2]辽宁大学化学系,沈阳110036

出　　处：《化学学报》1999年第9期992-996,共5页Acta Chimica Sinica

基　　金：辽宁省自然科学基金资助课题;中国科学院基金资助课题

摘　　要：在温度为278.15～318.15K范围内测定了含有不同Li_2B_4O_7和CaCl_2浓度测试液的无液接电池:Pt,H_2(101.325kPa)|Li_2B_4O_7(m_1),CaCl_2(m_2)AgCl-Ag的电动势E(V).在Pitzer电解质溶液理论基础上,用线性外推法确定离子对[CaB(OH)_4]~4的标准缔合常数K_d,并得到K_d随温度T变化的经验公式:pK_d=0.6857-359.72/T-4.632×10^(-3)T.同时计算得到了离子对缔合过程的热力学函数,指出形成该离子对的推动力是缔合熵.Emfs for the cell without liquid junction: Pt, H2(101.325kPa)| Li2B4O7(m1), CaCl2( m2)| AgCl - Ag are reported at five temperatures from 278.15 to 318.15 K. The standard association constant of ionic pair [CaB(OH)4] + , Kd is determined by fitting to the cell results. The dependence of pKd on temperature T is expressed by an empirical equation: pKd = 0.6857 - 359.72/T-4. 632×10 -3 T. The other thermodynamic quantities of the association process are also calculated. The results show that the driving force for the ion association reaction is association entropy.

关 键 词：水溶液 热力学 硼酸盐 离子对 缔合常数 电动势 

分 类 号：O611.65[理学—无机化学]