“铜元素化合物”的高三线上主题式复习*

以高三复习课“铜元素化合物”的教学为例,基于主题教学思想,从“价类二维图”出发,引导学生从物质类别、氧化还原和化学平衡等多角度认识元素化合物间的相互转化,实现了主题内容的关联与进阶,促进了学生思维能力的提升和学科观念的建构。本节课是网络直播课,采用“腾讯课堂”平台,学生可以连麦回答问题,学生设计的实验方案发布在班级微信上,由教师共享屏幕,则所有学生可见。     

促进学生有机物认识方式发展的烃、卤代烃单元复习教学研究

在烃、卤代烃单元复习教学之前,探查了学生对有机物的认识方式和基础知识的掌握情况,进而将复习课的核心教学目标定位为"建立基于化学键的有机物认识方式,促进学生有机物认识方式的发展"。基于复习教学目标,设计了认识性任务、问题、活动及其具体的教学过程,通过设计2种任务类型实现同课异构。通过教学实践,分析教学效果,探讨促进学生有机物认识方式发展的有效教学策略。     

手持技术和POE教学策略在高三复习中的应用——以“弱电解质的电离平衡”教学为例

通过"弱电解质的电离平衡"的高三复习课的课例分析,阐述了手持技术实验和POE教学策略在高三复习中的应用,能起到发展学生思维能力,有效突破教学重难点的作用和效果。     

熟手-新手化学教师“化学键”课堂教学行为特征比较研究

通过对熟手教师和新手教师的6节常态课堂中教学行为对类型、所用时间以及分布特征进行对比分析,发现熟手教师在各个小类教学行为对上的使用、教学行为转换上好于新手教师,新手教师在教学行为对使用的时间利用率上低于熟手教师。在常态课教学中,熟手教师和新手教师都应该多尝试采用开放度较高的教学行为对,新手教师要更加关注学生,引导学生思考,积极参与课堂。     

“复杂问题简单化”的教学思考——从“共价键与分子结构”复习课说起

"复杂问题简单化"是复习教学的普遍追求,以"共价键与分子结构(选修)"复习课教学为例,分析了教师对"复杂问题简单化"的认识,提出了教学设计注意的问题。     

复习课应回归教学原点——基于“沉淀溶解平衡”复习课设计的几点思考

高三化学复习课过分强调情境化,削弱了教学实效性。复习课的功能包括唤醒、重组和提升。"沉淀溶解平衡"教学设计包括引入归真、呈现归真、演绎归真和拓展归真等。复习课教学应关注精当的问题容量、精彩的教学预设和精准的学情掌控。     

组织学生进行溶液复习的尝试

初中化学第四章溶液的复习课教学中,用“五步法”组织学生复习,取得了较好的教学效果。现简介如下：第一步：复习准备教师以教材、大纲为依据,结合学生在学习溶液时易错、常错、易于忽略和混淆的问题,运用溶解度曲线,编写复习讨论题,引导学生复习、练习、理解、记忆。具体如下：     

论证“是否应该停止使用氮肥”社会性科学议题教学——氮及其化合物的复习

“氮及其化合物”复习教学中,通过社会性科学议题“是否应该停止使用氮肥”,在真实复杂的两难问题情境中,使学生基于物质类别和元素价态视角分析、设计氮肥的制备、使用以及减少其对环境影响中涉及的含氮物质的转化,提高学生自主应用氮元素“价-类”二维图综合分析、解决真实问题的能力,促进证据推理与模型认知、科学探究与创新意识、科学态度与社会责任等多维度化学学科核心素养的融合发展。经过多轮教学改进,结合教学效果抽提出以下教学策略：课上课下统筹安排,合理设置任务,提高学生参与议题的兴趣,促使学生全身心投入对议题的探讨;聚焦真实问题解决,将议题的探讨过程与关键能力持续进阶紧密结合并相互促进;让学生经历“做真事、真做事、真反思、真发展”的完整过程。     

“生命活动的物质基础”复习课教学与反思

利用"营养快线"饮料建构了"生命活动的物质基础"复习课,让学生体验食品中的化学,再到生活中的化学,最后到自然界中的化学,感悟化学是无处不在的。同时,在复习课教学中,利用化学实验手段、化学思维方式和化学符号向学生展示了化学学科特色,渗透了"化学观"教育,培养了学生的学科素养,在收获知识的同时提升能力。     

基于“前置性学习”的有效课堂生成教学——“硝酸的性质”教学反思

基于"前置性学习",课前建立教师与学生交流的平台,为教师更有效地进行课堂教学提供基础。结合"硝酸的性质"教学,阐述了"前置性学习"在元素化合物教学中课前如何设计、课中的如何延伸和拓展,最终实现学生乐学、好学的好课。     

"Alpha"-, "beta"- and "delta"-anhydrodigitoxigenin

The syntheses of 3β-hydroxy-5β-carda-14, 20:22-dienolide (= «β»-anhydro-), 3β-hydroxy-5β-carda-8:14, 20:22-dienolide (= «α»-anhydro-) and «δ»-anhydro-digitoxigenin (= probably 3β-hydroxy-5β, 14β-carda-8, 20:22-dienolide) by the best ways known to date, have been described. «δ»-Anhydro-digitoxigenin represents the thermodynamically most stable isomer. In this isomer the double bond in position 8 is unaffected by hydrogenation with Pt in acetic acid; with perbenzoic acid an epoxide results from which, on hydrogenation, the double bond can be regenerated in its original position. Analogous reactions are known to occur in the 8:14-epoxides.     

化“材”为“筑”

Chemistry is a central, practical and creative discipline. The development of chemistry plays an important role in the progress of science and society, as well as the improvement of the quality of human life. This paper introduces the chemical knowledge of stone, concrete, glass and other inorganic nonmetallic building materials by the anthropomorphically story. Taking nanomaterials as an example, the prospect of building materials development in the future is put forward.     

"Turn-on" fluorescent sensing with "reactive" probes

Chemical probes are valuable tools for the investigation of biochemical processes, diagnosis of disease markers, detection of hazardous compounds, and other purposes. Therefore, the development of chemical probes continues to grow through various approaches with different disciplines and design strategies. Fluorescent probes have received much attention because they are sensitive and easy-to-operate, in general. To realize desired selectivity toward a given analyte, the recognition site of a fluorescent probe is designed in such a way to maximize the binding interactions, usually through weak molecular forces such as hydrogen bonding, toward the analyte over other competing ones. In addition to such a supramolecular approach, the development of fluorescent probes that sense analytes through chemical reactions has witnessed its usefulness for achieving high selectivity, in many cases, superior to that obtainable by the supramolecular approach. Creative incorporations of the reactive groups to latent fluorophores have provided novel chemical probes for various analytes. In this feature article, we overview the recent progress in the development of turn-on fluorescent probes that are operating through chemical reactions triggered by target analytes. Various chemical reactions have been implemented in the development of many reactive probes with very high selectivity and sensitivity toward target analytes. A major emphasis has been focused on the type of chemical reactions utilized, with the hope that further explorations can be made with new chemical reactions to develop reactive probes useful for various applications.     

Making "wheels" and "cubes" from triangles

[Mn(IV)Mn(II)3] triangular units directed by the presence of tripodal alcohols self-assemble in the presence of azide and acetate ligands to form either a [Mn24] "wheel" or a [Mn32] "cube".     

"Clickable" polymersomes

Polymersomes, composed of amphiphilic polystyrene-block-poly(acrylic acid) (PS-b-PAA), with the periphery being covered with azide groups, were used for further functionalization using "click" chemistry.