在化学微观认识学习中发展学生科学本质理解的思考

发展学生对于科学本质的理解是科学教育的一个重要目标。在化学微观认识学习中发展学生科学本质理解的基本要点是：（1）化学微观认识是建立在事实基础之上发展起来的;（2）化学微观认识属于科学理论知识,是人类建构的说明物质微观世界的可能性认识;（3）化学微观认识之所以合理是因为较为满意的从微观结构的角度解释和预测了物质的性质。发展学生科学本质理解的基本思路是：（1）以WWHW为架构对化学微观认识进行认识论思考;（2）以“横纵关照”为基本技术构建发展科学本质理解的教学目标;（3）设计具有认识论意义的教学主题;（4）通过显性话语发展科学本质理解;（5）通过反思性活动发展科学本质理解;（6）适当评价学生对于科学本质的理解。     

理科职前教师科学模型理解的调查研究

就科学模型的理解对553名理科职前教师进行问卷调查。结果发现：（1）职前教师对科学模型的认识处于中上水平,仍需进一步提高;（2）科学模型的多个维度之间职前教师的理解水平相当;（3）职前教师对科学模型的认识并非随年级逐渐递增,具有不稳定性、反复性;（4）专业学习内容的差异对教师科学模型的认识有着重要影响;（5）科学模型的认识性别差异不明显。基于此提出了关于理科职前教师教育中加强科学模型教学的3点启示。     

国际科学教育中学生物质微粒性认识的研究进展

“物质微粒性”(PNM)是科学教育中的大概念之一,在国际科学课程中占有重要的地位。通过分析近20年国际科学教育相关研究文献,梳理了PNM的理论溯源、内涵、学生认识模型、制约因素及教学策略,阐明了当前国际科学教育领域对学生PNM认识的研究进展,为我国化学课程改革研究提供参考。     

例谈体现科学概念本质的教学设计

在分析与原子核、p轨道、杂化轨道相关迷思概念的基础上,以原子结构为例,探讨了教学设计如何在不改变常用术语的前提下,通过赋予科学概念以新的内涵,使其更加接近科学概念的本质。结合科学认识的发展,将更为体现事物本质的理论与模型转化为学生易于接受的形式进行呈现,同时帮助学生认识科学理论的构造性特征,可以促进学生形成对科学知识的批判性理解。     

何鸣元院士对绿色碳科学的认知与贡献

本文以何鸣元院士的代表性学术活动,概述了其对绿色碳科学的认知与贡献.首先介绍了何鸣元院士对分子筛催化裂化过程中三个层次矛盾的分析,以及针对矛盾内涵的关键问题,取得的催化裂化科学与技术的新认识和创新突破.进而,针对化石资源利用引起的碳失衡问题,在认识含碳物质化学键演变规律的基础上,何先生等提出了绿色碳科学的概念.     

科学教育评价新领域:科学身份

世界经济合作与发展组织(OECD)于2020年3月发布了《PISA 2024:科学评价策略愿景与指导框架》,计划在2024年PISA科学测评框架中引入一个新的评估领域--“科学身份”。以该框架为基础,探讨科学身份的内涵、科学身份建构的阶段性过程、科学身份评价的重点维度,以及科学身份评价对科学教育实践和评价的重要意义。     

从科学概念本体和发展史视角对化学平衡相关问题的分析

中学化学教学中关于化学平衡的认识存在多种误区,本文先从科学概念本体的视角系统考察了化学平衡的相关概念,对各种认识误区进行了分析,明确了原有分析化学平衡问题的视角的缺陷;再从科学概念发展史的视角探讨了化学平衡问题的分析方法,确立了符合热力学基本规律的更科学、更实用的化学平衡问题的分析工具——平衡常数;最后明确了基于平衡常数的化学平衡的相关认识及其基于平衡常数的平衡观构建的重要价值,可促进教师更加科学地认识化学平衡问题,关注并在教学中落实化学平衡常数的教学价值,为中学化学中四大平衡的教学提供借鉴和参考。     

在化学教学中进行科学素质教育的实践

探讨了在化学课堂教学中培养学生科学素质的基本方法:微观思维和科学探究;探讨了在化学课堂教学中培养学生的科学认识过程和科学认识方法;介绍了在化学课外活动中进行科学素质教育的方法:开设科技讲座、开展科技活动、进行创新实践;简要介绍了进行科技实践活动所取得的成果.     

高中生科学模型认识观的结构与特点

主要调查广东省337名高中生科学模型认识观的结构与特点。先用探索性因子分析初步确定量表中的因子数,再由验证性因子分析进一步检验量表的信度与效度,最后采用多元方差分析测查学生科学模型的认识观是否存在年级差异。     

促进学生认识发展的化学平衡教学设计研究

基于认识方式有关理论及高中生化学平衡认识模型,分析高中生在化学平衡从必修到选修的认识发展情况,进行促进学生认识发展的教学设计,实施课堂教学,并对比传统以知识获得为主的课堂教学,通过学生实际认识测查数据说明促进学生认识发展型教学优于传统教学。建议教师充分挖掘化学平衡常数的认识功能与价值,围绕化学平衡常数开展课堂教学,建立和发展学生对化学平衡的认识。     

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.     

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.     

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.     

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).     

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.     

Thermochemistry of Bu<Subscript>4</Subscript>NBr solutions in binary solvents containing formamide

The heats of solution of tetrabutylammonium bromide have been measured in mixtures of formamide (FA) with methanol (MeOH) and ethylene glycol (EG) at 313.15 K by calorimetric method. The standard enthalpies of solution in binary mixtures have been extrapolated to infinite dilution by Redlich–Rosenfeld–Meyer type equation using the literary data at 298.15 K and the present paper data at 313.15 K. The Debye–Hückel limiting law slope A _H required for calculation of the ∆_sol H ⁰ value has been obtained with application the new additive scheme of determination of the physic-chemical characteristics of binaries. The scheme is tested on the example of Bu₄NBr solutions in FA–MeOH mixture at 298.15 K. Its application yields the ∆_sol H ⁰ value very closed on the ones determined with the real (non-additive) characteristics of binaries. The standard enthalpies of solution extrapolated by Redlich–Rosenfeld–Meyer type equation are in a good agreement with the ones computed in terms of the Debye–Hückel theory in the second approximation. The heat capacities characteristics of Bu₄NBr have been calculated in H₂O–FA, MeOH–FA and EG–FA mixtures using the literary and present data. The sequence of solvents H₂O > FA > EG > MeOH located on their ability to solvophobic solvation found by us earlier for enthalpic characteristics is confirmed by the ∆C _p ⁰ values. The comparison of thermochemical characteristics of Bu₄NBr solutions in aqueous and non-aqueous mixtures containing FA has been carried out. The own structure of water remains in the region of small additions of formamide to co-solvents. It considerably differs the H₂O–FA mixture from the investigated non-aqueous systems.