国内外“物质的量”主题教学研究现状述评

分别以“Web of Science”与“中国知网”数据库为检索源,对2000—2020年间国内外“物质的量”主题研究论文进行检索,根据论文的研究内容进行分类归纳。研究表明:目前“物质的量”主题教学研究主要涉及:概念历史考量、教材研究、教师发展、学生认知与教学策略研究等5个方面。通过探析国内外的相关研究成果,以期为国内相关研究与实践提供有益借鉴。     

宏观与微观结合的化学教学实践——以“认识化学键的极性和分子的极性”为例

立足化学核心素养,凸显“宏微结合”,以“认识化学键的极性和分子的极性”一课的教学设计与实施为例,以牙签小实验引出化学问题,在习得化学键的极性和分子的极性理论知识之后,再回到生活中有机分子的极性特点,引出表面活性剂的系列性质,由宏入微、由微知宏、宏微结合,实现化学核心素养的落地。     

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。     

“教、学、评”一体化的化学课堂教学评价目标设计

精准设计评价目标是有效开展教学评价,实现“教、学、评”一体化的前提和保证。化学课堂教学评价目标的制订需要围绕教学目标合理规划学习任务和学习活动,依据学习活动承载的素养功能和水平,结合相关学业质量水平的要求,准确定位评价角度和评价水平。以“物质的量及其单位--摩尔”课时教学为例来说明评价目标的科学制订和规范表达。     

高中生对“物质的量”概念群的理解水平测查

通过编制信度、效度可靠的测量工具对高中生“物质的量”概念群的理解水平进行测查,发现大部分学生主要处于部分理解并伴随一定的误解的理解水平;学生对各概念的理解均存在迷思概念;学生在“物质的量”概念群中的迷思概念共计14条。     

基于变构学习模型的高中化学“导致悖论”教学设计*

“导致悖论”教学是一种智在创境、妙在引领的教学,其核心理念源自于变构学习模型的悖论思想,给学习者创造一个“肯定→否定→肯定”的反思性学习过程。高中化学教学设计可以通过4种途径分别创设“概念与概念”相悖、“理论与实验”相悖、“理论与理论”相悖和“实验与实验”相悖的悖论情境,最终实现学生新旧概念的更替和高阶思维能力的发展。“导致悖论”教学在实施中要注意精选合适的知识内容,加强学生心理的调控,提供丰富的支撑材料。     

国际科学教育视角下1-9年级学生“物质”核心概念进阶维度研究

概念转变理论、认知架构理论、概念形成理论都验证了核心概念建构的重要性。基于核心概念建构的进阶路径,介绍了学生理解“物质”概念进阶表征框架、“物质”和学生能力水平进阶表征框架、“物质”结构的学习进阶表征框架、“物质”核心概念区块理论表征框架和“物质”概念描述理论表征框架,并以“水的认识”为例分析了其构造图和结果空间。基于美国、英国、澳大利亚、爱尔兰、新加坡、加拿大阿尔伯塔省、加拿大安大略省、中国台湾、中国大陆9个国家或地区1至9年级科学课程文件,梳理了学生“物质”核心概念,并从“成分与辨识”“性质与应用”“变化与转化”3个视角划分了学生“物质”核心概念进阶维度,介绍了“物质”核心概念进阶测量方法,以期对我国科学教育有所启示。     

日本初中理科教科书中“粒子的存在”内容选择及启示

日本理科课程中“粒子”科学概念主要与化学课程相关,“粒子的存在”是“粒子”的首要核心概念,主要发展学生从微观层面认识物质的性质、结构及2者之间关系的能力,明确物质是由粒子构成的,粒子包括分子、原子和离子等,且粒子的性质决定物质的性质。从“重要事实”“核心内容”和“主要观念”3个方面自下而上对日本《新科学》教科书中“粒子的存在”相关内容的选择进行分析,发现《新科学》教科书在内容选择上具有注重“粒子模型”构建的层次性和观念层面要求显性化的特征。     

高中生对化学核心概念掌握情况的测查分析——以“电解质、离子反应、化学键”概念群为例

电解质、离子反应、化学键组成一个核心概念群,是学生掌握相关知识的重难点。对北京市普通高中370名高二学生的测查显示:(1)概念掌握的程度为:化学键<离子反应<电解质。(2)“电解质的概念”与“导电原理”“离子反应概念”“离子共存”的掌握程度存在显著相关;电离与离子反应概念的掌握程度显著相关;“导电原理”与“离子反应概念”“离子共存”“离子键与共价键综合辨析”的掌握程度显著相关。表明电解质的概念、导电原理的理解与掌握是概念体系中的重要纽带。(3)优秀、中等、学困3类学生在解决容易和较难2类概念的相关问题上差异最大,而中等难度上的差异相对较小。基于此,提出了相应的核心概念教学对策。     

高中生“化学平衡”概念结构的研究

根据认知心理学关于概念结构的理论,对高中生“化学平衡”概念的自由分类进行多维标度和聚类分析,得出高中生的“化学平衡”概念由2个维度组成,学生的分类属于关联聚类,揭示了影响学生概念结构的因素,并对概念教学提出了建议。     

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.     

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。     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

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.

     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

解决能源问题的新途径——光解水制氢的研究

面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。