KBr-H2O、NH4Br-H2O和ZnBr2-H2O作用浓度计算模型

建立了强电解质水溶液KBr-H2O、NH4Br-H2O和ZnBr2-H2O作用浓度的计算模型,计算了上述三个溴化物二元水溶液体系在温度为298.15K、质量摩尔浓度达到饱和前的作用浓度.热力学模型计算的组元作用浓度以纯物质为标准态和摩尔分数为浓度单位,与文献报道的组元活度以无限稀为标准态和质量摩尔浓度为浓度单位经过活度的标准态转换后可良好地吻合,且转换系数在计算的浓度范围内基本守恒.以上热力学模型计算的组元作用浓度能反映出强电解质水溶液的结构本质;在本模型的假设下电解质水溶液呈现理想溶液特征,组元的作用浓度在计算的浓度范围内严格遵守质量作用定律.

Calculating models of mass action concentrations for KBr(aq), NH4Br(aq) and ZnBr2(aq) binary solutions

The calculating models of mass action concentration for electrolyte aqueous chloride solutions KBr-H2O,NH4Br-H2O,and ZnBr2-H2O were founded at 298.15 K to calculate the molalities before saturation according to the ion and molecule coexistence theory and the mass action law.The calculated mass action concentration is based on pure species as the standard state and mole fraction as the concentration unit,and the reported activities are usually based on infinite dilution as the standard state and molality as the concentration unit.Hence,the calculated mass action concentration must be transformed to the same standard state and concentration unit.The transformation coefficients between calculated mass action concentrations and the reported activities of the same component fluctuate in a very narrow range.Thus,the transformed mass action concentrations not only agree well with the reported activities,but also strictly obey the mass action law.It is indicated that the new developed models can embody the intrinsic structure of the investigated three electrolyte aqueous solutions.Electrolyte aqueous solutions have characters of ideal solution under the assumed condition.The results also show that the mass action law has its widespread applicability to electrolyte binary aqueous solutions.