配平复杂氧化还原反应的系数问题

任何反应都要根据实验事实来确定其生成物,然后写出相应的化学方程式。上述反应的实质是KMnO4在酸性介质条件下氧化H2S。     

氧化-还原反应方程式逆向配平之技巧

关于氧化-还原反应方程式配平,同学们普遍感到:已掌握的配平原则、步骤对一般反应式的配平较顺利,当遇到较复杂的,按部就班似乎行不通.如下述方程式如何迅速地配平,让我们共同探讨.     

关于“配平复杂氧化还原反应的系数问题”

本刊在1982年5期60页上发表了一个解答。邹沐民同志提出了不同意见,肯定了第一个配平式而否定了第二个配平式。还有好几位读者,如王明华、张福兴、孙广华、曾庆辉等同志来信来稿提出了不同的意见。这些意见是宝贵的,饶有趣味的。     

有机物氧化-还原反应方程式的配平

熟知有机物氧化-还原反应方程式的配平可以使我們正确地写出有机物氧化-还原反应的完整方程式来,而且使我們加深对氧化-还原反应的认识。然而在涉及到有机物的氧化-还原反应时,人們往往忽略反应     

关于氧化-还原反应方程式配平的教学

氧化-还原反应作为化学反应的一种类型,有其普遍性和重要性.元素的原子在构成物质时,由于外围电子的得失或共用而建立起化学键,在化学反应中随着原子的离合与重组发生键的破裂与重建.在上述过程中,键合电子的隶属关系常发生变化,因此氧化一还原反应是一种常见的反应类型.     

谈氧化——还原反应方程式配平的教学

不少初学化学的同学反映,氧化—还原反应式的配平不好掌握。分析其原因:一是一些同学对“基本的”氧化—还原反应式配平还不甚了解的时候,盲目“拔高”;也有的教师忽略学生认识能力,一下子深刻地讲了“全部”氧化—还原反应式配平的许多例子,学生来不及用自己认知结构同化所学新知识,囫囵吞枣。     

介绍一种有机氧化还原反应的配平法

有机氧化还原反应方程式的配平,对于研究和定量计算有机反应是很重要的。但由于有机氧化还原反应比无机反应更为复杂,因此,用直观或氧化数法直接配平整个反应方程式就更加困难。本文介绍一种利用氧化还原反应中相互联系、不可分割的氧化与还原两个半反应,以配平有机氧化还原反应方程式的方法。这种所谓的半反应法比较简便,又易于掌握。为了理解和掌握半反应法,首先应当弄清有机化学中的氧化还原概念。在有机化学中,氧化反应一般是指有机物脱氢或得氧的过程,而还原反应是指加氢或失氧的过程。因此,烃转变为醇、醇转变为醛、醛转变为酸是氧化反应,其逆过程是还原反应;而烷转变为烯、烯转变为炔是氧化反应,其逆过程是还原反应:     

对“配平复杂氧化还原反应的系数问题”一文的商讨

阅读本刊1982年第5期问题解答栏“配平复杂氧化还原反应的系数问题”一文后,觉得有欠妥之处,现提出来和作者、编者商讨。     

高中化学氧化还原反应方程式配平技能学习进阶的探讨

氧化还原反应方程式配平技能是学生需要发展的化学基本技能之一。从学生需要的基础技能、氧化还原反应的复杂性、教科书教学内容的安排、高考的命题和考试要求这4方面讨论了影响氧化还原反应方程式配平技能的因素。对在“化学1”模块阶段、高考总复习阶段中,氧化还原反应方程式配平技能的学习过程进行分析,提出1个包括4个预期水平的预期水平方案。最后分别对围绕氧化还原反应方程式配平技能的教学实践、学术研究提供建议。     

有机氧化还原反应方程式的一种配平法：代数法

有机氧化还原反应方程式的一种配平法──代数法李致冉（山东大学化学系，济南２５０１００）有的文献［１］和教科书￣［２］曾介绍过配平有机氧化还原方程式的两种方法，即半反应法和氧化数法。本文介绍另一种方法——代数法。它的具体步骤是：第一，写出基本反应式；第...     

Computer Simulation of the Kinetics of Complicated Gas Phase Reactions

Modern digital methods and powerful computers make it possible to simulate the time behavior of chemical reactions. These calculations can be performed on systems containing an almost unlimited number of elementary reactions. Generally, however, the reaction models used should contain only those elementary reactions which describe the bulk of the conversion. Such a reaction model may be obtained by reduction of the complete set of elementary reactions. Another possibility is analysis of the chemical system starting from conditions ensuring a simple chemistry, which is generally the case at low temperatures and low conversions. The reaction model may then be extended into the range of the reaction variables (temperature, time) of interest. Mathematical simulations may be helpful during the development of the reaction model, and sometimes even decisive. These methods were applied to the pyrolysis of ethylbenzene and n-hexane, and to CO oxidation. They yield information on the reaction paths, the importance of particular elementary reactions, and reaction stability. Furthermore, quantitative data can be obtained concerning the influence of single elementary reactions on the product distribution. The sensitivity matrix shows, e.g., whether the determination of kinetic parameters of an elementary reaction from kinetic data of the overall reaction is possible in principle, and how high the accuracy of the rate constants should be for simulation of the reaction. Both results are important for modeling chemical reactions.     

基于单核配位反应的定量演进方程

提出了定量演进方程的概念,用于描述单核配位反应过程中各组分的量的变化规律。定量演进方程将通过反应过程中的质量平衡以及反应物的体积比来建立。本文结果表明定量演进方程可很好地揭示单核配位反应过程各组分的浓度演进图景,有助于学生直观把握单核配位反应的进程。同时,定量演进方程也可用于稳定常数的计算。     

A Cognitive Modeling Tutor Supporting Student Inquiry for Balancing Chemical Equations

Improved interactive tutoring capabilities in educational software for chemistry problem solving is an important need that has been clearly articulated by teachers and students. The purpose of this work is to examine the incorporation of new concepts from the field of artificial intelligence (AI) as a route to meaningful individualized tutoring. The basic shift is to replace specific foreknowledge of problems with a direct representation of chemical and pedagogical principles and then simulate reasoning using these principles to tutor students. To assess the potential of an AI-based approach, we have developed a prototype tutorial program for balancing chemical equations that contains two important advances. First, the system can create a worked-out solution with detailed explanations for any equation entered by the student or teacher. Unlike a conventional tutorial, this is done dynamically, without the equation being stored ahead of time. Second, the program can interactively answer a variety of detailed questions about its work at each step. Studying worked-out examples plays an important role in learning, and this approach to supporting interactive student inquiry is being investigated as a method of cognitive modeling and apprenticeship intended to foster the students own self-explanation and question-asking abilities.     

Quantitative Description of Polymerization Reactions by Means of Multiparameter Equations

Linear free energy relations are successfully extended to the principle of polylinearity when propagation is the predominant rate-determining step and others (e.g., initiation, termination) can be neglected. The cationic polymerization of vinyl ethers and p-substituted styrenes provides improved insight into the mechanism. On the other hand, the overall rate of the homopolymerization or the relative reactivity of the cross-propagation step in copolymerization can be controlled by means of multi-parameter equations. Some examples are given where multi-parameter correlation analysis with rather empirical parameters are shown useful for controlling industrial processes as well as for definite product formation.     

氧化还原反应中2个重要关系式用于求算非氧化还原反应平衡常数的方法讨论

电化学中的KƟ-EƟ关系式和φ-φƟ关系式是分别求算原电池氧化还原反应平衡常数和氧化还原电对电极电势的重要公式。实际上,这2个公式也可以用来求解非氧化还原反应的平衡常数。以实例的形式讨论了这一思想的根据、方法,及其在求算水电离常数、弱酸或弱碱电离常数、难溶性电解质溶度积常数和配离子形成常数等方面的应用。     

A New Singular Matrix Method for Balancing Chemical Equations and Their Stability

In this work is given a new singular matrix method for balancing new classes of chemical equations which reduce to an n × n matrix. The method offered here is founded by virtue of the solution of a homogeneous matrix equation by using of Drazin pseudoinverse matrix. The method has been tested on many typical chemical equations and found to be very successful for the all equations in our extensive balancing research. This method works successfully without any limitations. Chemical equations treated here possess atoms with fractional oxidation numbers. Also, in the present work are analyzed some necessary and sufficient criteria for stability of chemical equations over stability of their reaction matrices.     

Method for Estimating Efficiency Factors for Complex Reactions: I. Reactions Occurring via Several Stoichiometric Equations

The method for estimating the efficiency factors proposed by Temkin for a multicomponent reaction described by a single stoichiometric equation is extended to reactions described by several stoichiometric equations. The proposed approach makes it possible to find the efficiency factors of key substances by solving a set of nonlinear equations. The capabilities of the method are illustrated using the reaction of steam reforming of methane as an example.     

通识化学:有机物燃烧方程式的简易配平法

在通识化学的教学层面上,面向不同背景的学生,以简单有机物完全燃烧的化学方程式的配平为主题,梳理数学方法在化学方程式配平中的应用和特点,采用跨学科的方式,让学生能从不同的角度进行思考和学习,以掌握数学方法在化学中的应用。     

Balancing the Initiation and Molecular Recognition Capabilities of Eosin Macroinitiators of Polymerization‐Based Signal Amplification Reactions

Coupling polymerization initiators to molecular recognition events provide the ability to amplify these events and detect them using the formation of a cross‐linked polymer as an inexpensive readout that is visible to the unaided eye. The eosin‐tertiary amine co‐initiation system, activated by visible light, has proven utility in this context when an average of three eosin molecules are coupled to a protein detection reagent. The present work addresses the question of how detection sensitivity is impacted when the number of eosin molecules per binding event increases in the range of two to fifteen. Unlike in other initiation systems, a non‐monotonic relationship is observed between the number of initiators per binding event and the observed detection sensitivity.

     

A Concise Description of an Old Problem: Application of Matrices to Obtain the Balancing Coefficients of Chemical Equations

It is not difficult to balance chemical equations and thus it is hardly given more thoughts. However, there is a mathematical principle for the balancing of chemical equations and this principle may be used for automation. The balancing of chemical equation is carried out, by formulating a reaction matrix and the latter is used in a matrix equation. The matrix equation is then solved to obtain the balancing coefficients. The conventional matrix inverse method cannot always be used and hence the solution is obtained by row reduced operations. These operations and any matrix manipulation are carried out with Matlab. Further this novel method can be used to classify chemical equations as nonfeasible, unique and nonunique.