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1.
通过新旧课标与教材的对比分析,在大概念的统领下,确定“合成高分子”的教学目标以及认识方式。以“结构决定性质,性质决定用途”大概念统领单元教学,围绕教学目标选择新冠疫情下的“防病毒口罩”为情境,在真实问题的解决过程中发展学生认识合成高分子的基本思路,促进学生化学学科核心素养的发展。  相似文献   

2.
“水溶液”是中学化学的核心内容主题,改进和优化水溶液复习教学至关重要。通过对高三学生水溶液复习前的问卷调查与访谈、分析已有水溶液复习教学研究和复习教学指导文件、梳理学生关于水溶液认识发展的已有研究,综合确定了高三水溶液复习教学中学生的具体认识发展点,基于此设计了促进学生认识发展的高三水溶液的单元整体复习教学,并且进行了教学实践,取得了较好的教学效果。在此基础上探讨了基于学生认识发展点的复习教学的核心策略。  相似文献   

3.
李小静  艾璐 《化学教育》2023,(19):79-87
在教学单元知识结构及承载的素养发展功能、教学现状、学情分析的基础上,制定“物质的组成与结构”单元目标及课时目标,设计每课时的教学流程,并以导引式大概念建构课“物质成分的探究”为例进行单元教学实践,培养学生基于宏观、微观、宏微结合的视角认识物质成分的意识,发展学生的核心素养,并进行实践反思。  相似文献   

4.
高中生化学概念发展水平测查结果表明,学生化学概念发展中存在2个问题:(1)认识角度尚待丰富;(2)认识水平尚需提高。当前课程改革实践过程中,概念教学"过程与方法"维度目标设计中存在一系列问题。将认识方式发展目标落实到具体内容的"过程与方法"维度教学目标当中,为解决学生概念发展过程中存在的2个问题及教师在教学目标设计过程中存在的问题提供了可行的途径。  相似文献   

5.
王维臻 《化学教育》2019,40(13):23-27
我国最新一轮的课程修订将小学科学课程起始年级从3年级调整至1年级。在大概念理念下,1年级学生应该学习哪些内容才能有效促进其大概念的发展开始受到越来越多的关注。以物质学习为例,基于大概念视角讨论1年级学生对于物质应该建构何种认识,并提出了相应的教学建议。  相似文献   

6.
何彩霞 《化学教育》2010,31(9):30-32
化学概念是学生化学学习的重要内容。化学概念的教学不应只关注具体概念内涵的识记和辨析,而应关注学生的思维过程,教给学生科学加工的方法,使之成为认识物质及其变化的思想工具。本文以“混合物和纯净物”概念教学为例,对案例中的教学问题进行了多角度分析,并从了解学生已有的知识经验、明确学生化学概念学习水平和认识发展目标、创设经历思维过程的学习活动3个方面阐述了促进学生认识发展的概念教学设计思路。  相似文献   

7.
学科大概念是单元整体教学设计的核心。从教学内容、学情、试题进行教学现状分析,基于课程标准、学科本质、学生认知构建学科大概念,进行学科大概念统领下的高三有机复习教学设计与实践,促进学生化学学科核心素养的发展。  相似文献   

8.
朱鹏飞  陈敏  陈凯 《化学教育》2018,39(23):37-42
以高中化学“离子反应”概念教学为例,阐述了发展学生化学学科核心素养的课例研究思路和教学活动设计。围绕离子反应概念、离子方程式书写、离子反应发生条件等知识内容,挖掘教学内容与学科核心素养内涵的联系,创设真实且富有价值的问题情境,开设高水平的实验探究活动,注重微观分析过程,将离子反应概念的学习与从微观离子角度分析水溶液中反应的认识思路进行整合,力求发展学生的化学学科核心素养,帮助学生形成对“离子反应”概念的整体认识。  相似文献   

9.
邱惠芬 《化学教育》2016,(19):38-40
以"溶解度"的概念教学为例,分析概念建构过程中如何促进学生的认识发展。在概念教学中,应关注学生的前科学认识,挖掘学生的认识角度和思路,发展学生的认识方式,从而形成学生的认识能力。  相似文献   

10.
刘健  郑长龙  康波  宁晓强 《化学教育》2022,43(17):73-79
以“物质成分”大概念教学为例,基于学科理解,以探究物质成分的相关化学史为线索设计教学,引导学生在追溯“物质成分”相关概念、理论的发展过程中,逐渐建构物质成分的宏观、微观、宏微结合视角。并在解决探究物质成分的真实问题的过程中,培养学生基于证据进行推理的科学论证能力,通过认识视角的发展,体会科学理论是在不断发展和进阶的,初步建立科学发展观。  相似文献   

11.
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.  相似文献   

12.
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。  相似文献   

13.

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.

  相似文献   

14.
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.  相似文献   

15.
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。  相似文献   

16.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
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^-。  相似文献   

17.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

18.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

19.
袁丽秋 《化学教育》2006,27(5):8-10
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。  相似文献   

20.
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