Nadeem Syed Muhammad Saqib, Saeed Rehana, Ali Moattar
Department of Chemistry, University of Karachi Room No. 309, 3rd Floor Karachi-75270 Pakistan
RSC Adv. 2025 Sep 24;15(42):35201-35218. doi: 10.1039/d5ra03403e. eCollection 2025 Sep 22.
Densities of pure water, aqueous maltose, and aqueous lactose solvents were measured at temperatures of 303.15, 308.15, 313.15, 318.15, and 323.15 K before and after the addition of different concentrations of copper(ii) sulfate. The density of water, aqueous maltose, and aqueous lactose solvents increased with the addition of copper(ii) sulfate, while an increase in temperature decreased the density. The apparent molar volume ( ) of copper(ii) sulfate solutions was calculated from the density data by using a standard mathematical relationship. The decreased with the increase in the concentration of copper(ii) sulfate and is also affected by the nature of the solvent and temperature. The limiting apparent molar volume ( ) was evaluated by using Masson's and Redlich, Rosenfeld, & Meyer's equations. The structure-breaking or structure-making behavior of copper(ii) sulfate was evaluated by calculating Hepler's constant (δ /δ ) . A negative value of Hepler's constant in water and aqueous maltose solvent confirmed the structure-breaking behavior of copper(ii) sulfate, whereas a positive value of Hepler's constant in aqueous lactose solvent is indicative of the structuring of the solvent. The limiting apparent molar expansibility ( ) and isobaric thermal expansion coefficient ( ) were also evaluated from the to provide supporting evidence for the obtained conclusions.
在添加不同浓度的硫酸铜之前和之后，分别在303.15、308.15、313.15、318.15和323.15 K的温度下测量了纯水、麦芽糖水溶液和乳糖水溶液溶剂的密度。随着硫酸铜的添加，水、麦芽糖水溶液和乳糖水溶液溶剂的密度增加，而温度升高则使密度降低。通过使用标准数学关系，根据密度数据计算硫酸铜溶液的表观摩尔体积（ ）。 随着硫酸铜浓度的增加而降低，并且还受溶剂性质和温度的影响。通过使用马森方程以及雷德利希、罗森菲尔德和迈耶方程来评估极限表观摩尔体积（ ）。通过计算赫普勒常数（δ /δ ） 来评估硫酸铜的破坏结构或形成结构行为。在水和麦芽糖水溶液溶剂中赫普勒常数的负值证实了硫酸铜的破坏结构行为，而在乳糖水溶液溶剂中赫普勒常数的正值表明溶剂的结构化。还从 评估了极限表观摩尔膨胀系数（ ）和等压热膨胀系数（ ），以提供所得结论的支持证据。
