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基于化学核心素养,以“打开第二自然界的大门”开启甲烷的科学探究与体验之旅,在“历史线”“活动线”“知识线”等3条认知与体验路线中,经历科学概念的形成过程,实现对“稻草变黄金”科学本质的理解,有效地将HPS教育与化学核心素养结合起来,使学生体会化学发展的过程与方法,感受化学的学科魅力和发展成就,以提高学生的学习兴趣。 相似文献
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基于“素养为本”视角,以“原子晶体”的教学为例,对教学主题内容、教学现状及学情进行分析;以发展学生化学学科核心素养为主旨确定教学目标;以“微粒-微粒间的相互作用-物质的聚集状态-物质性质”的认识思路为主线,以“模型认知,建构概念-证据推理,归纳性质-微观探析,探究结构-科学史实,揭示价值”的任务型教学流程,达到落实并发展学生化学学科核心素养的目的。 相似文献
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“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。 相似文献
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在高中必修阶段“原子结构 元素周期律”主题已有研究的基础上,将“位构性”系统模型与学科能力活动任务相结合,提出了本研究的理论框架,进行了单元整体的教学设计并实施。通过预设学生的表现水平,设计各课时的评价任务,过程性地诊断学生在各个课时中“位构性”模型建构与学科能力的发展水平,描述学生在本章学习过程中的发展变化,促进了学生“证据推理与模型认知”等核心素养的发展。最后,归纳出以“位构性”模型建构和学科能力发展的“原子结构 元素周期律”在教学实践中的有效策略。以期能够对日后开展“原子结构 元素周期律”主题的教学设计与实践能够提供参考和建议。 相似文献
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为了反映化学学科发展的特点和趋势,充分突显现代科学技术发展的新成就。以“三谱解析阿司匹林”的4个教学环节为例,着重阐述质谱、红外光谱、核磁共振氢谱在有机物分子结构探究教学中的运用策略,从而建构出探究有机物分子结构的一般模型,培养学生的证据推理与模型认知的化学核心素养。 相似文献
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以“设计净水系统”为项目主题,介绍了项目教学主题选取、项目目标确定、项目规划、实施与评价策略。项目教学中,关注学生认知与思维发展,随着净水系统的设计、制作、测试和再设计项目学习活动的展开,引导学生综合运用化学、物理、数学等多学科知识方法分析解决问题,促进学生提炼真实情境下“物质分离与提纯”解决思路,发展化学学科核心素养,同时体验和感受完整的工程设计过程。 相似文献
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Areas of fusion and crystallization peaks of K3TaO2F4 and KTaF6 were measured using the DSC mode of a high-temperature calorimeter (SETARAM 1800 K). On the basis of these quantities, considering
the temperature dependence of the calorimeter sensitivity, values of the fusion enthalpy of K3TaO2F4 at the fusion temperature of 1181 K of (43 ± 4) kJ mol−1 and of KTaF6 at the fusion temperature of 760 K of (8 ± 1) kJ mol−1 were determined. 相似文献
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Russell G. Baughman Kenneth L. Martin Rajendra K. Singh James O. Stoffer 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(2):o103-o106
In 2,4‐dihydroxybenzaldehyde 2,4‐dinitrophenylhydrazone N,N‐dimethylformamide solvate {or 4‐[(2,4‐dinitrophenyl)hydrazonomethyl]benzene‐1,3‐diol N,N‐dimethylformamide solvate}, C13H10N4O6·C3H7NO, (X), 2,4‐dihydroxyacetophenone 2,4‐dinitrophenylhydrazone N,N‐dimethylformamide solvate (or 4‐{1‐[(2,4‐dinitrophenyl)hydrazono]ethyl}benzene‐1,3‐diol N,N‐dimethylformamide solvate), C14H12N4O6·C3H7NO, (XI), and 2,4‐dihydroxybenzophenone 2,4‐dinitrophenylhydrazone N,N‐dimethylacetamide solvate (or 4‐{[(2,4‐dinitrophenyl)hydrazono]phenylmethyl}benzene‐1,3‐diol N,N‐dimethylacetamide solvate), C19H14N4O6·C4H9NO, (XII), the molecules all lack a center of symmetry, crystallize in centrosymmetric space groups and have been observed to exhibit non‐linear optical activity. In each case, the hydrazone skeleton is fairly planar, facilitated by the presence of two intramolecular hydrogen bonds and some partial N—N double‐bond character. Each molecule is hydrogen bonded to one solvent molecule. 相似文献
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科学史奠基者乔治·萨顿在《科学史导论》第二卷的第一部分对我国宋代酿酒著作《北山酒经》予以了简要描述,出现了“spirits”“distillation”等字样;而《北山酒经》被众多学者认为其描述对象是发酵酒(黄酒)。本文从东西方蒸馏技术和相关著作的文本分析对《科学史导论》中提及的蒸馏技术和蒸馏酒存在的可能性提出了质疑。 相似文献
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The corroding process of six glasses of the Na2O-K2O-CaO-ZrO2-SiO2 system with ZrO2content 0–2.13 mass % by water was observed during static tests at 121°C and pressure of 0.25 MPa in steam sterilizer. Significant
increase of Na+ and K+ content in leachates was observed after the addition of ZrO2 into glass. Further increase of the content of ZrO2 in glasses slowed down the rate of Na+ and K+ leaching. The leaching process of SiO2 as well as Na+, K+, and Ca2+ ions was evaluated on the basis of comparison with model leaching processes. Variation of the concentrations of Na+, K+, Ca2+, and SiO2 in leachates with time was described by empirical equation. Observed changes in the initial leaching rates of Na+, K+, Ca2+, and SiO2 can be ascribed to the content of ZrO2 in glasses. The presence of ZrO2 in glasses reduced the overall rate of glass dissolution. 相似文献
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I. B. Bakhtiyarly D. Sh. Abdinov R. A. Ismaiyilova E. A. Geidarova 《Russian Journal of Inorganic Chemistry》2008,53(4):624-627
Phase equilibria in the Sb2Te3-Gd2Te3-Bi2Te3 ternary system have been studied using differential thermal analysis, namely, X-ray powder diffraction, microstructure examination, thermodynamic analysis, and microhardness and alloy density measurements. Phase diagrams of some polythermal joins and liquidus surface have been constructed. The regions of primary crystallization of phases and the coordinates of all invariant and univariant equilibria in the system under investigation have been established. 相似文献
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N. V. Pervukhina S. V. Borisov S. A. Magarill D. Yu. Naumov V. I. Vasiliev B. G. Nenashev 《Journal of Structural Chemistry》2004,45(4):720-723
The results of structural studies of the synthetic analog of the radtkeite mineral Hg3S2Cl1.00I1.00 are analyzed. The crystal structure of the compound has been refined; the unit cell parameters are a
m = 16.827(4) , b
m = 9.117(1) , c
m = 13.165(5) , = 130.17(2)°, V = 1543.3(8) 3, space group C2/m, Z = 8, R = 0.0527. A possible transition a
0
= a
m; b
0
= a
m + 2c
m; c
0
= –b
m to the pseudo-orthorhombic F cell previously determined for radtkeite, where one of the angles (
0
) is slightly different from 90° (89.55°), has been found. Each sulfur atom in the structure is bonded to three mercury atoms, forming SHg3 umbrellas with distances 2.240(6) –2.474(8) and angles HgSHg 94.7(2)°–102.9(2)°. The SHg3 fragments are linked through Hg vertices to form corrugated [Hg12S8] layers. The halogen atoms lie inside and between the [Hg12S8] layers; the distances are Hg-Cl and Hg-I 2.783(7) , 2.961(7) , and 3.083(4) –3.311(3) , respectively.Original Russian Text Copyright © 2004 by N. V. Pervukhina, S. V. Borisov, S. A. Magarill, D. Yu. Naumov, V. I. Vasiliev, and B. G. NenashevTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 755–758, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date. 相似文献
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A. V. Shlyakhtina A. E. Ukshe L. G. Shcherbakova 《Russian Journal of Electrochemistry》2005,41(3):265-269
A nanoceramic product of the composition Lu2Ti2O7 is synthesized by a coprecipitation method with a subsequent sublimation drying and an annealing at 650–1650°C. The conduction of Lu2Ti2O7 synthesized at 1650°C is ionic (10–3 S cm–1 at 800°C). Thus, a new material with a high ionic conduction has been discovered. The ordering in Lu2Ti2O7 is studied by methods of RFA, RSA, IK spectroscopy, electron microscopy, and impedance spectroscopy. The existence of a low-temperature phase transition fluorite-pyrochlore at 800°C and a high-temperature conversion order-disorder at 1650°C are established.Translated from Elektrokhimiya, Vol. 41, No. 3, 2005, pp. 298–303.Original Russian Text Copyright © 2005 by Shlyakhtina, Ukshe, Shcherbakova. 相似文献
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Teresa Zaremba 《Journal of Thermal Analysis and Calorimetry》2008,92(2):583-587
The study presents results of examination on Na0.5Bi0.5TiO3 (NBT) ferroelectric synthesis through intermediate binary compound Bi4Ti3O12 (BIT). The first stage of the study related to obtaining BIT from oxide precursors, i.e. Bi2O3 and TiO2. The second stage included obtaining NBT from Bi4Ti3O12, Na2CO3 and TiO2. Two polymorphic modifications of TiO2 (anatase, rutile) and diversified initial homogenization of raw material batches were applied during examination. 相似文献
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V. M. Novotortsev S. F. Marenkin I. V. Fedorchenko A. V. Kochura 《Russian Journal of Inorganic Chemistry》2010,55(11):1762-1773
The results of studying phase equilibria of ternary AIIBIVCV systems have been reported. Physicochemical foundations have been developed for the synthesis of new ferromagnets with Curie
temperatures above room temperature structurally compatible with basic semiconducting materials. Methods of synthesis and
physicochemical properties of manganese-doped AIIBIVC2V ferromagnets have been described. The results of theoretical simulation of magnetic properties have been considered and basic
approaches to the explanation of the emergence of ferromagnetism in AIIBIVC2V doped with 3d metals have been surveyed. The most promising ways to produce and study dilute magnetic semiconductors as spintronics materials
have been presented. 相似文献
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Quantum-chemical calculations of the geometry and energies of nine possible isomers of 12-vertex cobaltacarborane CpCoC2B9H11 (1) were carried out by the DFT method (PBEPBE/DGDZVP/DGA1). Thermodynamic stability of the isomers increases with increasing
distance between the carbon atoms in the cage and is virtually independent of the position of the CpCo vertex. The relative
stabilities of the 1,2,3-(17.57 kcal mol−1), 1,2,4-(3.72 kcal mol−1), and 1,2,9-isomers of 1 (0 kcal mol−1) are similar to the corresponding values for the ortho (17.61 kcal mol−1), meta (3.21 kcal mol−1), and para isomers (0 kcal mol−1) of carborane C2B10H12. The results of the present study confirm a close similarity of the CpCo and BH fragments in metallacarborane chemistry.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1557–1559, July, 2005. 相似文献