初中化学“酸的性质复习”项目化教学——制作牙膏

以牙膏的制作为主线,通过认识口腔环境、选择牙膏材料、测定主材含量、动手制作牙膏等4个项目任务,复习酸的通性,拓展酸的个性。从元素观、转化观的视角认识物质转化规律,体现物质研究的一般思路,凸显科学探究的基本过程;构建验证无明显实验现象的反应发生的思路;建立混合物中定量测定某成分的方法;总结商品设计的思路及原则;深化物质组成决定性质、性质决定用途的学科观念。呈现一节利用已学化学知识解决真实问题的案例,有效培养学生的科学态度与社会责任,发展学生的质疑能力、批判能力、证据推理能力和创新意识。     

初中化学“氧化物的复习”教学实录及反思

实录了1堂"氧化物的复习"的课堂教学过程。以氧化物知识复习为主线,将游戏的元素和方法融入教学情境,从元素观、转化观和分类观的视角去认识和剖析氧化物及其转化规律,体现了物质研究的一般方法,呈现了1堂学科观念教学的具体课例,凸显了元素化合物知识复习的基本流程和思想方法。     

化学科学理解的基本视角及其核心观念

物质及其转化是化学科学的基本问题,也是化学学科教学的回归性问题。化学科学认识活动对其基本问题“物质及其转化”的认识有2大基本任务：一是探寻“物质及其转化”的基本规律,一是建构“物质及其转化”的科学理论。元素视角是化学科学认识其基本问题“物质及其转化”规律性的独特视角。微观认识是化学科学理解或解释其基本问题“物质及其转化”规律性的独特思维方式。元素观、能量观、科学本质观是化学科学的核心观念。     

信息技术与“教学评”一体化深度融合的教学实践*——以“有机合成”为例

以建构有机合成中的顺推法和逆合成分析法思维模型为载体,通过设置驱动任务,将信息技术和“教学评”一体化深度融合,促进学生结构观、发展观和转化观的形成,理解有机化学的社会价值,培养学生的宏微结合、变化观念、科学态度和社会责任等化学学科核心素养。     

化学学科观念建构是单元教学的核心——“物质的分类”单元教学的思考

物质的分类是高一学生学习化学的一个重要内容,其中贯穿着分类方法。如何根据这部分知识内容的特点和学生的学习实际,引导学生从化学的视角对物质进行分类,促进学生化学学科基本观念如元素观、分类观、转化观等的初步形成,这无疑是极为重要的。本文从“物质的分类”单元教学的角度出发,分析了本单元内容的教学价值,从化学学科本质的角度阐述了对“物质分类”的理解,在此基础上提出了基于学科观念建构的单元教学策略。     

在真实情境中发展核心素养的高三有机化学复习教学案例——以“香豆素3羧酸乙酯的合成”为例

基于高三有机化学复习特点,以真实情境为载体,设置综合复杂程度不同的问题,引导学生从有机化合物官能团转化的角度预测物质结构、设计转化路线;从碳骨架和化学键变化的角度理解反应过程,理解共价键的类型、极性与有机反应的关系;利用物理性质设计分离提纯方案,体现出学科内的融合。使学生真正建立“组成、结构决定性质”的基本观念,凸显对比分析、逆合成分析等有机推断问题解题思路,发展高阶思维,促进学生关键能力的提升,促进化学学科核心素养的发展。     

基于认识视角与认识思路的化学课堂教学*——物质的分类及转化

以解决“保存NaOH溶液的试剂瓶为什么不用玻璃塞”这一真实问题为情境,设计3个教学板块:运用分类方法认识物质、对物质进行分类、合成物质,从物质组成和物质变化的认识视角,对物质进行分类,建构分类观。依据物质分类研究同一类别物质的性质及应用,在完成知识结构化的同时,重在凝练基于物质分类及转化的认识视角和认识思路,寻找并体验陌生情境下解决复杂化学问题的突破口和思维框架,发展学生的化学学科核心素养。     

初中化学“溶解现象”项目式教学*——从海带中提取碘和甘露醇

围绕“海带中碘的检验和提取”和“甘露醇的提取”2个社会生活情境展开,通过流程图的制作、流程问题的探讨、实验的具体操作以及课后拓展研究等4组任务,来完成“溶解现象”章节复习,建构工业流程的认知模型,理解“溶解、溶液、溶解度、结晶”等学科概念,渗透元素观、微粒观、平衡观等学科观念,发展设计探究实验、数据分析与证据推理等学科关键能力。     

迷宫游戏助力元素观建构的二氧化硫复习教学

学科观念对学生的学习和发展起着重要而持久的迁移作用。元素观是化学学科的核心观念,元素观的建构有助于学生对物质世界形成有序的认识,并为其他化学观念的形成提供基本框架。高三复习阶段,以元素化合物知识和概念原理知识为依托,借助迷宫游戏进行思维活动,促使学生不断反思、概括、提炼学科事实性知识,将客观存在的、知识形态的元素观念逐步转化为学生脑海中的元素观。     

基于化学学科核心素养的初高中衔接教学——初三化学“金属的化学性质”

“金属的化学性质”是初高中化学学习的重要内容,该部分内容涉及到重要的化学观念和化学学科核心素养,如元素观、转化观、微粒观、STS观,以及宏观辨识与微观探析、证据推理与模型认知素养。但是初三学生认知水平受限,在教学中不能深入电子转移的微观角度,不能充分认知模型、应用模型。为弥补这一问题,本研究基于化学学科核心素养,进行“金属的化学性质”的初高中衔接教学研究。     

The enthalpies of combustion and formation of <Emphasis Type="Italic">L</Emphasis>-α-glutamic and 6-aminohexanoic acids

Summary The energies of combustion of crystalline L-α-glutamic and 6-aminohexanoic acids were measured in a static bomb adiabatic calorimeter, in pure oxygen at 3040 kPa. Corrections were made for the heats due to the ignition of sample and for the nitric acid formation. The derived enthalpies of formation for L-α -glutamic and 6-aminohexanoic acids are Δ_fH_cr⁰= -1002.6±1.1 kJ mol^-1and Δ_fH_cr⁰= -641.6±1.2 kJ mol^-1, respectively. The data of enthalpy of formation are compared with literature values and with estimated values by means of group additivity, using parameters recommended by Domalski and Hearing.     

Structral Effects on the Mutual Solubility of Solution Components and Formation of Zinc and Cadmium Chloride Complexes in Zn(Cd)(NO<Subscript>3</Subscript>)<Subscript>2</Subscript>-LiCl-H<Subscript>2</Subscript>O Systems

Solubility isotherms have been determined for Zn(Cd)(NO₃)₂-LiCl-H₂O systems at 25°C, and Raman spectra in the range of M-Cl and nitrate ion vibrations have been measured. A single bond system is realized over the whole range of concentrations in the Zn(NO₃)₂-LiCl-H₂O system because the cybotactic groups are structurally compatible. In the Cd(NO₃)₂-LiCl-H₂O system, the cybotactic groups are incompatible, which leads to structural microheterogeneities in post-eutectic concentrations.Original Russian Text Copyright © 2004 by M. K. Khripun, A. A. Kiselev, A. Yu. Efimov, L. A. Mund, and V. P. Petranovskii__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1027–1033, November–December, 2004.     

Study of non-isothermal crystallization of amorphous Cu<Subscript>50</Subscript>Ti<Subscript>50</Subscript> alloy

The crystallization kinetics of amorphous Cu₅₀Ti₅₀ has been studied using differential scanning calorimetry (DSC) under non-isothermal conditions. The curves at different linear heating rates (2, 4, 8 and 16 K min^–1) show sharp crystallization peaks. The crystallization peak shifts to higher temperatures with increasing heating rate. The Kissingers method of analysis of the shift in the transformation peak is applied to evaluate the activation energy (E _c). The KJMA formalism, which is basically developed for isothermal experiments, is also used to obtain E _c and the Avrami parameter (n).The DSC data have been analysed in terms of kinetic parameters, viz. activation energy (E _c), Avrami exponent (n) and frequency factor K ₀ using three different theoretical models. It is observed that the activation energy values derived from KJMA approach and modified Kissinger equation agree fairly well with each other. The activation energy values obtained from normal Kissinger method, and Gao and Wang expression underestimate the activation energy.The financial support provided by All India Council for Technical Education (AICTE), New Delhi (Govt. of India) is gratefully acknowledged.     

Standard molar enthalpies of formation of [RE(Gly)<Subscript>4</Subscript>(Im)(H<Subscript>2</Subscript>O)](ClO<Subscript>4</Subscript>)<Subscript>3</Subscript> (<Emphasis Type="Italic">RE</Emphasis>=Eu,Sm)

The two complexes, [RE(Gly)₄(Im)(H₂O)](ClO₄)₃(s)(RE = Eu, Sm), have been synthesized and characterized. The standard molar enthalpies of reaction for the following reactions, RECl₃·6H₂O(s)+4Gly(s)+Im(s)+3NaClO₄(s) = =[RE(Gly)₄(Im)(H₂O)](ClO₄)₃(s)+3NaCl(s)+5H₂O(l), were determined by solution-reaction colorimetry. The standard molar enthalpies of formation of the two complexes at T = 298.15 K were derived as Δ_f H _m^Θ {Eu(Gly)₄(Im)(H₂O)}(ClO₄)₃(s)} = = −(3396.6±2.3) kJ mol⁻¹ and Δ_f H _m^Θ {Sm(Gly)₄(Im)(H₂O)}(ClO₄)₃(s)} = −(3472.7±2.3) kJ mol⁻¹, respectively.     

从科学哲学的视角分析科学课堂教学——以“质量守恒定律”为例

以“质量守恒定律”为例,选取科学革命、科学问题、科学实验、归纳与重复、解释与预测等几个视角对科学课堂教学的各个环节进行了分析。通过分析,各环节中所蕴含的科学哲学内容得以显现,对科学课堂教学的认识更为全面,对科学本质的认识更加深刻。     

Prediction of compounds related to InFeZn<Subscript>2</Subscript>O<Subscript>5</Subscript>

The results of crystal-chemical analysis of layered hexagonal structures related to InFeZn₂O₅ and having space group P6₃/mmc are reported. It was found that more than 250 new compounds could be synthesized. Multilayered compounds of other compositions are possible.     

Insertion of cations into WO<Subscript>3</Subscript> investigated by QCM techniques

The electrochemical insertion of Li⁺, Na⁺, and hydrogen ions into thin layers of WO₃ was investigated with the help of an electrochemical quartz crystal microbalance. Solutions of perchlorates in propylene carbonate were used as electrolytes, and the first cycle of coloration/discoloration cycles was studied. In both cases, insertion of cations was accompanied by a massive and partly irreversible uptake of the solvent in a molar ratio from 1:1 to 1:2 (ion vs solvent). The insertion of Na was observed for the first time. Molecules of water coinserted with H⁺ indicated that the inserted species is H₃O⁺ rather than merely a proton H⁺. Very small but observable insertion of Mg²⁺ from perchlorate/PC solution proceeded in a marginal but observable extent from ClO₄ ^-/PC solution.     

Thermal oxidation of cellulose investigated by chemiluminescence. The effect of magnesium and calcium carbonates and of different pHs

Whatman cellulose impregnated with calcium and magnesium carbonates was oxidized and chemiluminescence accompanying this oxidation has been measured. It was shown that magnesium ions in deacidified cellulose pulp promote the light emission significantly. On the other hand, acid papers give the more pronounced light signals at temperatures close to ambient. The relation between chemiluminescence runs and paper degradation has been implicated, with an attempt to extrapolate half-lives of paper samples to conditions close to ambient. To cite this article: J. Rychlý et al., C. R. Chimie 9 (2006).     

Electrotransport properties of ions in aqueous solutions of H<Subscript>2</Subscript>SeO<Subscript>4</Subscript> and Na<Subscript>2</Subscript>SeO<Subscript>4</Subscript>

Coefficients of self-diffusion, absolute speeds of movement of ions and the activation energy of electrical conductivity are found from the conductance measurements of aqueous solutions of selenic acid and sodium selenate at different concentrations in a temperature range of 288–318 K. Both the Stokes and effective radii of ions and their hydrate numbers at 298 K are calculated. The obtained results are interpreted in the frames of Samoilov theory on positive and negative hydration of ions.     

Bibliometric Analysis of the <Emphasis Type="Italic">Journal of Structural Chemistry</Emphasis>

Bibliometric analysis has been carried out for the Journal of Structural Chemistry (JSC) published since 1960 by the Siberian Branch of the Russian Academy of Sciences. All JSC publications which appeared between 1960 and 2002 have been chosen online from the Chemical Abstracts and Science Citation Index databases of the STN International net and analyzed according to topics, authors, affiliations, and other criteria. JSC authors and publications with the largest numbers of citations have been identified. The impact factor has been determined for JSC 2002.Original Russian Text Copyright © 2004 by V. M. Buznik, I. V. Zibareva, V. N. Piottukh-Peletskii, and N. I. Sorokin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1142–1153, November–December, 2004.