关于等物质的量规则的形成与探讨

正1985年赵梦月等首先提出了等物质的量规则~([1])。等物质的量反应规则的内容详解及举例,参见文献~([2])。它受到化学界的广泛重视、热烈讨论和积极思考,已被不少作者采用~([1,3-5])。同时,在国家标准的起草中,也得到了充分运用~([6-7])。广大的化学工作者也经常使用等物质的量规则,进行相关的专业教学、学生试验、溶液配制与计算、日常化学检测、仲裁分析和科研开发等活动。     

等物质的量规则及其应用

为了在化学中,尤其在分析化学中贯彻执行《关于在我国统一实行法定计量单位的命令》、《中华人民共和国计量法》以及有关量和单位国家标准,必须废除“当量”、“当量浓度”、“当量定律”。为了解决废除当量定律后分析化学中的计算问题,作者曾提出了“等物质的量规则”。等物质的量规则是在当量定律基础上,根据化学反应的客观规律,利用物质的量及其导出量(物质的量)浓度的定义提出的,既继承     

基于概念认识功能的教学案例*—以“物质的量”为例

分析了“物质的量”概念教学存在的2个问题:概念结构不清晰,忽视概念之间关系的建立,概念的呈现不能从原有认知出发;忽视概念的认识功能,将物质的量仅仅当成计算的工具。提出在教学中从初三原有化学定量出发,从朴素的个数定量和宏观的质量定量发展到科学的化学计量—物质的量,借助板书建立了物质的量从内涵到关系的概念结构图。呈现了突出物质的量的认识功能、促进化学计量认识发展的教学实录,包括概念建立、概念理解和概念应用3个环节,并通过访谈分析了教学效果和存在问题及改进方向。     

以物质的量为核心的化学计量系统构建及其产生式教学策略

从认知心理学知识学习角度分析以物质的量为核心的化学计量系统,从教学策略角度,可以将其划分为知识系统和操作系统2大部分,其知识系统主要属于陈述性知识,而操作系统则主要属于程序性知识。按照陈述性知识的认知特点设计体现物质的量相关知识系统网络结构功能的探究教学;按程序性知识的认知规律设计产生式自展过程等较高层次的思维运作。从而形成了以物质的量为核心的化学计量系统知识建构的探究教学方法与实际问题解决的小步子产生式策略。其意义在于以结构化系统替代零散知识,用逻辑性思维替代常识比喻,以智能化产生替代机械运算,为以物质的量为核心的化学计量系统教学探索更加有效的策略与方法。     

盐酸滴定碳酸钠第二化学计量点碳酸浓度的探讨

盐酸滴定碳酸钠第二化学计量点碳酸的浓度是溶液的pH值的计算依据，碳酸的浓度应该根据等物质的量反应原理，利用反应溶液的浓度具体计算得出，同时，应该明确说明计算时忽略碳酸的分解这一前提条件。     

品味"物质的量"教学

《化学教育》2003年第6期刊登了朱文祥、裴毅两位老师“让我们给‘物质的量’命个名”一文。文章指出“物质的量”作为一个物理量名称的不严谨为学生及化学工作者带来诸多不便。介绍了英、美等国化学教材、专著中“mole”概念的引入、使用。作者认为十分必要给“物质的量”取个特定的名称,     

对等物质的量规则的认识

在分析化学中,废除了以当量为基础的当量定律后,有些学者提出了等物质的量规则的理论,并在新编分析化学教材中得到了应用。但是,对等物质的量规则尚持有不同的看法。本文首先剖析了等物质的量规则,并提出了一种表述等物质的量规则的方法,然后阐述了等物质的量规则的优越性以及使用等物质的量规则计算时应注意的几个环节。     

“物质的量”概念的探讨及其有关计算方法之我见

物质的量是物理化学和分子物理学这门学科范围的基本量。长期以来,人们习惯用当量,当量浓度及摩尔浓度等现已废弃的单位去计算。而当前国际单位制(SI)以物质的量作为基本量。为了使大家对物质的量能正确的理解和使用,本文特对其概念进行了讨论,并提出了与之适应的计算方法。     

碳酸氢钠受热分解实验

为了使高一学生加深理解摩尔这一概念和掌握有关摩尔最基本的化学计算,笔者从日本高中理科用的化学教材中摘译了碳酸氢钠分解实验。该实验的主要特点是能把有关物质的量、摩尔质量、摩尔数、气体摩尔体积等基本概念既能严格地加以区分,又能有机地统一在同一个实验之中。     

容量分析中的物质的量计算

在量和单位的国家标准中,当量及其有关的量均被废除,代之而出现了物质的量及其有关的量,自然当量定律也被废除,代之而出现了等物质的量规则。由于当量及其有关的量和当量定律在分析化学中使用很久,人们已非常习惯,加之人们对国家标准中物质的量及其有关的量和等物质的量规则不太熟悉,因此在分析化学计算上还存在不少问题,如何在分析化学计算中应用等物质的量规则,在教学中是应该探讨的。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。