三元体系Na2SO4-CuSO4-H2O 25 ℃活度系数的研究

用自制的Hg-Hg_2SO_4电极和Na离子选择性电极, 在25 ℃和离子强度分别为1.0和2.0的条件下, 测定了Na_2SO_4在Na_2SO_4和CuSO_4混合水溶液中的平均活度系数。对所使用的电极组的热力学响应、重现性等性能进行了检验。根据文献提供的Pitzer方程, 推导了计算Na_2SO_-CuSO_4-H_2O体系中Na_2SO_4和CuSO_4平均活度系数的表达式, 求出了Pitzer混合参数和Harned方程系数, 计算了CuSO_4在该体系中的平均活度系数。     

电解质溶液活度系数测定实验的改进

用电动势法测定AgNO3稀溶液的离子平均活度系数(γ±),操作简单、方便,且由于AgNO3是1-1价型电解质,其稀溶液的lgγ±-I曲线与Debye-H櫣ckel极限公式所预期的结果比较接近。将实验结果与文献值比较,有较好的准确度。     

Fe2(SO4)3/γ-Al2O3固体超强酸的Mossbauer谱研究

采用浸渍法制备了一系列Fe2(SO4)3/γ-A12O3型固体超强酸样品,用Mossbauer谱和XRD研究了不同温度处理对样品中铁组分的存在状态及稳定性的影响,结果表明,随Fe2(SO4)3含量的变化,铁组分可以在γ-A12O3表面以单层分散和无定形形式存在;当温度≥600℃时,无定形状态的Fe2(SO4)3又生成晶态的Fe2(SO4)3,而形成的晶态Fe2(SO4)3即使在700℃时也不分解.     

萘在1-1价小离子盐水溶液中活度系数的研究(V)

本文用紫外分光光度法测定了25 ℃下萘在LiBr、NaBr,KBr、NH_4Cl、NaF及KF盐水溶液中的活度系数f。将萘的lgf分别对六种盐的浓度c_S作图, 得到通过原点的直线, 符合Setschenow盐析公式, 直线斜率就是盐析常数k。本文还计算了萘在盐水溶液中盐析常数的各种理论值, 并对各种理论值进行对比, Debye-MacAulay理论和McDevit-Long公式的计算值都较实验值大2—3倍。Conway等人理论的计算k值对不同盐差别很小, 而实验值彼此之间的差别却很大。对体积大的非电解质, 色散力对盐析常数的影响不可忽略。本文对Bockris公式进行修正, 计算结果表明, 它能较正确地指出盐效应的次序及盐析常数的符号。内压力理论改进公式的计算结果不仅能预言盐析常数的符号, 也能指出盐析常数大小的顺序, 理论值与实经值符合较好。     

LaCl3和Fe2(SO4)3对化学镀Ni-W-P的影响

三氯化镧;硫酸铁;非晶沉积;LaCl3和Fe2(SO4)3对化学镀Ni-W-P的影响     

多组分电解质溶液热力学 II.HCl-CoCl2-H2O体系中HCl的活度系数(298.15K)

中图分类号:     

RbCl在H2O-DMF混合溶剂中活度系数的测定

应用Corning-价阳离子选择电极（M~＋－ISE）和Orion氯离子选择电极组成可逆电池,CI~－－ISE|RbCl（m）,H2O（1－x）,DMF（x）M~ －ISE．测量该电池标准电动势E_m,运用扩展的Debye－Hckel公式,计算RbCl在283．15至318．15K七个温度下由H2O至H2O－DMF混和溶剂的标准迁移自由能ΔG和在不同组成（H2O－DMF）混合溶剂中平均离子活度系数γ±,并对迁移自由能及活度系数随混合溶剂有机物组份的摩尔分数的变化进行了讨论。     

电导法测定ErCl3在H2O中的活度系数

应用电导法测定了298K下E下ErCl3在水中的活度系数,并分析了浓度对电解质溶液活度系数的影响.     

固体酸Fe2(SO4)3催化合成丙酸异戊酯

Solid acid ferric sulphate Fe2(SO4)3 was prepared and used for the study of the catalytic synthesis of iso-amyl propionate. The optimun reaction conditions were follows: the ratio of amount of substance n(iso-amylalcohol) : n(propionic acid) = 1.5, the reaction time 2h, the catalyst quantity 1.5g, and dewatering solvent toluene 10ml. The yield was 97.2% under the optimum reaction conditions. The catalyst being of high catalytic activity for the esterification reactions was prepared very easily and could be used repeatedly.     

离子色谱法测定辛辣食品中的SO32-(SO2)含量

采用阴离子色谱-抑制电导检测器测定姜、蒜、辣椒、芥末、洋葱等带有辛辣气味的含硫食品中的亚硫酸盐(二氧化硫)残留量,采用酸性条件下的水蒸气蒸馏方法对样品进行提取纯化。线性范围为1．0～160．0mg／kg,回收率为80％～110％,满足出口食品检测要求。该方法适用于出口脱水菜和袋装水煮菜中SO3^2-(SO2)的测定。     

Physical chemistry of the zinc-bromine battery: I. Activity coefficients of aqueous zinc bromide

The potential of the cell Zn–Hg(2 phase)|ZnBr₂(m)|AgBr|Ag was measured from 0 to 35.9°C and for molalities from 0.125 to 4.0. From these results and values of the standard cell potential, activity coefficients of aqueous zinc bromide were calculated. Good agreement was found with the emf and isopiestic results of Stokes and Stokes, where the ranges of temperature and molality overlap. The activity coefficients of solutions more concentrated that 1.0m are much lower than those of strong 1–2 electrolytes, and this anomaly becomes more pronounced with increasing temperature.     

金属活动性顺序的探讨——由一道初中化学试题引发的思考

列举了金属活动性顺序只能说明反应的趋势,不能说明反应速率的例子。解释了一些常见金属活泼性强,反应速率反而慢的原因。指出并举例说明了一些反应不能用金属活动性顺序来判断反应的方向。总结了在使用金属活动性顺序时应考虑的几点内容。     

The Liquid Junction Potential in Potentiometric Titrations. VII. On Emf Titrations Proposed for the Determination of Some Interaction Coefficients

Certain galvanic cells without liquid junctions, used together with a titration technique, are proposed to determine interaction coefficients for the various ion pairs present in the solutions: The experimental values of the interaction coefficients are needed in calculations of the total emf of cells with liquid junctions considered in other papers of this series.     

电极电势:从电化学势说起*

对于原电池,电极电势的本质是化学体系对电极材料上电子势能的影响,其正负极电势差反映化学能向电能转化的趋势。电极界面上化学物质的氧化/还原反应是通过何种途径影响到电极上电子势能的,现有的教材和论著没有给出明确的解释。本文基于相间电化学势平衡原则阐明了固液界面上离子平衡与电极上电子电势的关系,并由此给出了标准电势的物理含义:它是构成电极体系一系列物性参数的组合,包括被测电极的电子、离子化学势,工作电极电解液的离子化学势,参比电极的电子、离子化学势和参比电极电解液的离子化学势等。     

Thermodynamic parameters for the protonation of carboxylic acids in aqueous tetraethylammonium iodide solutions

The protonation constants of 21 carboxylic acids (formic, acetic, propionic, benzoic, phenoxyacetic, salicylic, oxalic, malonic, succinic, itaconic, malic, tartaric, oxydiacetic, thiodiacetic, thiodipropionic, phthalic, maleic, citric, 1,2,3-tricarboxylic, 1,2,4-tricarboxylic and 1,2,4,5-tetracarboxylic), have been determined potentiometrically, by pH-metric measurements, at several temperatures and ionic strengths, 5T55°C, 0<11 mol-dm^–3, using tetraethylammonium iodide as background salt. General equations for the dependence on ionic strength of thermodynamic parameters have been found. The statistical significance of results and the possibility of using a simple model for the thermodynamics of carboxylic acids protonation, is discussed.     

On the standard potential of the mercury:Mercurous sulfate electrode at 25°C in aqueous solution

The standard potential of the mercury:mercurous sulfate electrode in aqueous solution at 25°C is determined in terms of the Weston saturated and Clark saturated standard cells. Eight electrode combinations involving cadmium-amalgam or zinc-amalgam electrodes and one lead-amalgam electrode are employed with the emf of the standard cells. A best value of 0.61544 V was obtained that agrees within 0.09 mV with the value previously reported by Harned and Hamer.     

电极电势计算器的设计开发与教学应用

电极电势是化学基础课教学中重要的物理量和基础数据,将现代信息化Python技术与电极电势教学深度融合,自主设计、开发了一款图形用户界面电极电势计算器.结合具体应用实例,以物料平衡和电荷平衡2个基本定量关系为基础,利用电对的电极还原反应和电极电势Nernst方程,首先介绍了计算器分别从标准电极电势和条件电极电势出发快速计算获取非标准状态下电极电势的2种途径,之后重点讨论了盐效应作用或酸效应、沉淀生成效应和配合物生成效应等副反应存在下电对条件电极电势的估算.电极电势计算器界面设计简洁,操作方便,具有较强的开放性、灵活性和普适性,无需安装和专业编程知识,可直接在Windows平台上运行,便于教师教学和学生自主探究学习.     

Predicted and experimental standard electrode potentials in liquid ammonia at 25°C

Methods are described for the prediction of standard Gibbs free energies of formation of monatomic and polyatomic ions in liquid ammonia at 25°C. Supplementation with auxiliary free energy data allows the tabulation of standard electrode potentials in 1 m acid liquid ammonia solutions for 143 half-reactions involving 58 elements.     

Activity Coefficients of Individual Ions from Titration Data

It is shown that the activity coefficients of the anions resulting from the dissociation of a weak polyprotic acid can be obtained from titration data. Activity coefficients are determined in terms of the activity coefficient of the undissociated acid. The extracted activity coefficients are also dependent on the pH scale adopted in the titration process and are considered as operational coefficients. The computational procedure uses an exact equation representing the titration curve and a nonlinear least-squares fitting procedure. As an illustration, the activity coefficients of the anions of succinic acid are determined. The method also allows study of the variation of the activity coefficients with the ionic strength in a straightforward manner.     

Linear free energy relationship correlations for the solubilising characterisation of room temperature ionic liquids containing 1-hexyloxymethyl-3-methylimidazolium and 1,3-dihexyloxymethylimidazolium cations

Gas-to-room temperature ionic liquid (RTIL) partition coefficients have been compiled from the published literature for solutes dissolved in 1-hexyloxymethyl-3-methylimidazolium bis(trifluoromethylsulphonyl)imide, {[HxomMIm]⁺[(Tf)₂N]^?}, and in 1,3-dihexyloxymethylimidazolium bis(trifluoromethylsulphonyl)imide, {[(Hxom)₂Im]⁺[(Tf)₂N]^?}. These partition coefficients are converted into water-to-RTIL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients are analysed using the Abraham model with cation-specific and anion-specific equation coefficients. The equation coefficients are reported for the 1-hexyloxymethyl-3-methylimidazolium and 1,3-dihexyloxymethylimidazolium cations. The calculated cation coefficients can be combined with our previously determined nine sets of anion-specific equation coefficients to yield expressions capable of predicting the partition coefficients of solutes in 18 different RTILs.