培养学生高级思维能力的“分子间作用力与物质性质”探究教学

探究教学的深入开展要求更加关注学生在探究过程中的自主性、创造性和问题解决能力。以"分子间作用力与物质性质"的教学设计为背景,详述了3个核心探究:范德华力的成因、范德华力的影响因素和氢键模型的建构。对实施创造性探究教学的策略进行了总结反思:在教学设计上,为学生打造展示和发展思维的环境;在实施探究教学过程中,教师要善于抓住机遇,充分展现学生的思维过程。     

分子间选择性作用力和控制论化学——金松寿教授研究简介

金松寿教授是著名的量子化学及化学动力学专家。年近九旬的他如今仍然锲而不舍地在学习、研究,把握化学研究的发展方向。他在催化集团结构适应性及无机化合物溶解度领域做了大量的工作,重要的成就是发现了选择性分子间力并用以阐释物性如溶解度、吸附、色谱中的反常现象,还可以解释溶媒对反应速度的影响。相似的选择力后来被外国科学家在超分子研究中得到证实和发展。他还推动了控制论化学的应用,对化学中的许多疑难繁琐的现象给出清晰满意的解释。     

分子间选择性作用力和控制论化学-金松寿教授研究简介

金松寿教授是著名的量子化学及化学动力学专家。年近九旬的他如今仍然锲而不舍地在学习、研究,把握化学研究的发展方向。他在催化集团结构适应性及无机化合物溶解度领域做了大量的工作,重要的成就是发现了选择性分子间力并用以阐释物性如溶解度、吸附、色谱中的反常现象,还可以解释溶媒对反应速度的影响。相似的选择力后来被外国科学家在超分子研究中得到证实和发展。他还推动了控制论化学的应用,对化学中的许多疑难繁琐的现象给出清晰满意的解释。     

手持技术数字化实验支持下的抽象化学概念学习*——以探究比较丁醇同分异构体的分子间作用力大小为例

根据TQVC概念认知模型设计手持技术数字化实验,比较丁醇同分异构体的分子间作用力大小,并应用“四重表征”理论对实验结果进行解释与分析。研究发现:蒸发时温度下降速度越快,同分异构体的空间位阻越大,其分子间作用力越小;同分异构体混合液的分子间作用力比任一组分的分子间作用力小。     

以实验和论证为杠杆撬动化学概念深度学习*——以“分子与原子”教学为例

以倡导“理解与批判、联系与构建、迁移与应用”的深度学习为理念,围绕“分子与原子的概念”比较教材与文献的设计思路,调整认知脉络,着力解决“概念学习过程中实验探究少,宏观现象进入微观分析的相关实验不匹配,忽略证据推理、变化观念与平衡思想核心素养”等不足。设计“3种形态的碘与淀粉的反应、H2O2溶液与品红反应、H2O2溶液的分解反应”3组实验,设置学生画分子模型、画H2O2分子分解的微观过程等活动,提炼“物质种类、分子种类、物质性质之间的关系是什么？你从实验中找到哪些证据支持观点？前2个单元的实验,还有哪些可作为论证的依据？”等问题,引发学生充分论证。“实验、活动、问题、论证”环环相扣,促成教学内容的有效结构化,通过化学概念的深度学习实现化学学科核心素养的发展。     

基于“手持技术”实验比较液体有机物分子间作用力大小——以醇类同系物和同分异构体为例

利用手持技术,通过测量不同的液体醇(同系物或同分异构体)在相同条件下蒸发时的温度变化曲线,以比较不同液体分子间的作用力,并得出以下结论:在相同条件下,蒸发时温度曲线下降幅度越大,下降速率越快的液体,其分子间作用力越小。     

促进学生个性化深度学习的教学策略设计——以“二氧化硫的性质和作用”为例

在BEM理论的基础上,分析常规课堂教学的弊端,提出“1-1-2问题模板策略”进行教学设计的建议,以苏教版《化学1》“二氧化硫的性质和作用”为例,展示学生进行个性化深度学习的实践探究过程。     

模型素材差异对初中生“分子和原子”概念认知水平影响的观测工具设计

模型是为了理解事物而对事物做出的一种抽象,不同模型对学生关于同一概念的认知理解会产生不同的影响。以初三化学“分子和原子”章节为载体,设计了可以观测模型素材差异对初中生“分子和原子”概念认知水平影响的3份工具。     

以“问题账单”引导学生自主建构化学概念——以“物质的分类”教学为例

以高中化学1"物质的分类"教学为例,分析了物质分类的教学价值与学生学习的困难,阐述了基于"问题账单"促进学生建构化学概念的教学整体思路,并就其中关键环节的设计进行了较为详细的说明,以问题为驱动引导学生体会建立物质分类的必要性,以问题为线索设置认知冲突、构建教学内容主线,呈现了类别概念建立的多种途径和方法。     

利用预测和实验的冲突促进探究学习——“原电池的工作原理”课例分析

实验在化学教学中起着重要的作用,实验探究是实验教学的重要手段.高中化学课堂中出现预设和实验冲突的现象,应该培养学生实事求是的学风、严肃认真的科学态度以及探讨问题的科学方法,帮助学生理解和运用化学基本概念、化学定律和化学原理.     

Intermolecular Forces of Sugars in Water

Summary. Apparent molar volume and viscosities of fructose, glucose, mannose, and sucrose have been measured in dilute aqueous solution, concentration range 0.028–0.336 M at 293 K. The viscosity coefficient B and A were calculated from the viscosity data using the Jones-Dole equation for all the studied sugars. The data were also analysed for Stauarding equation. The structure making behavior was obtained for all the sugars. A modified Jone-Dole equation was proposed by using ratio of mole fractions of solute and solvent in place of concentrations of solute.     

Intermolecular Forces of Sugars in Water

Apparent molar volume and viscosities of fructose, glucose, mannose, and sucrose have been measured in dilute aqueous solution, concentration range 0.028–0.336 M at 293 K. The viscosity coefficient B and A were calculated from the viscosity data using the Jones-Dole equation for all the studied sugars. The data were also analysed for Stauarding equation. The structure making behavior was obtained for all the sugars. A modified Jone-Dole equation was proposed by using ratio of mole fractions of solute and solvent in place of concentrations of solute.     

概念的建构过程应促进学生的认识发展——“溶解度”的教学与思考

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。     

Naphthazarin Derivatives in the Light of Intra- and Intermolecular Forces

Our long-term investigations have been devoted the characterization of intramolecular hydrogen bonds in cyclic compounds. Our previous work covers naphthazarin, the parent compound of two systems discussed in the current work: 2,3-dimethylnaphthazarin (1) and 2,3-dimethoxy-6-methylnaphthazarin (2). Intramolecular hydrogen bonds and substituent effects in these compounds were analyzed on the basis of Density Functional Theory (DFT), Møller–Plesset second-order perturbation theory (MP2), Coupled Clusters with Singles and Doubles (CCSD) and Car-Parrinello Molecular Dynamics (CPMD). The simulations were carried out in the gas and crystalline phases. The nuclear quantum effects were incorporated a posteriori using the snapshots taken from ab initio trajectories. Further, they were used to solve a vibrational Schrödinger equation. The proton reaction path was studied using B3LYP, ωB97XD and PBE functionals with a 6-311++G(2d,2p) basis set. Two energy minima (deep and shallow) were found, indicating that the proton transfer phenomena could occur in the electronic ground state. Next, the electronic structure and topology were examined in the molecular and proton transferred (PT) forms. The Atoms In Molecules (AIM) theory was employed for this purpose. It was found that the hydrogen bond is stronger in the proton transferred (PT) forms. In order to estimate the dimers’ stabilization and forces responsible for it, the Symmetry-Adapted Perturbation Theory (SAPT) was applied. The energy decomposition revealed that dispersion is the primary factor stabilizing the dimeric forms and crystal structure of both compounds. The CPMD results showed that the proton transfer phenomena occurred in both studied compounds, as well as in both phases. In the case of compound 2, the proton transfer events are more frequent in the solid state, indicating an influence of the environmental effects on the bridged proton dynamics. Finally, the vibrational signatures were computed for both compounds using the CPMD trajectories. The Fourier transformation of the autocorrelation function of atomic velocity was applied to obtain the power spectra. The IR spectra show very broad absorption regions between 700 cm−1–1700 cm−1 and 2300 cm−1–3400 cm−1 in the gas phase and 600 cm−1–1800 cm−1 and 2200 cm−1–3400 cm−1 in the solid state for compound 1. The absorption regions for compound 2 were found as follows: 700 cm−1–1700 cm−1 and 2300 cm−1–3300 cm−1 for the gas phase and one broad absorption region in the solid state between 700 cm−1 and 3100 cm−1. The obtained spectroscopic features confirmed a strong mobility of the bridged protons. The inclusion of nuclear quantum effects showed a stronger delocalization of the bridged protons.     

基于学生自主、合作学习过程的元素化合物课型教学实践——以“铁盐和亚铁盐的性质”为例

在“国培计划”高中化学观摩课“铁盐和亚铁盐的性质”的教学设计和教学实践中,通过向学生提供具有一定开放性和综合性的学习任务,学生在自主、合作学习过程中对元素化合物性质的学习内容产生深度思考,并对学习过程产生深度体验。教学结束后,通过问卷调查学生对自主、合作学习过程的自我评价,对元素化合物课型中促进学生自主、合作学习能力发展的教学理念和教学方法进行讨论。     

Competition of Intra- and Intermolecular Forces in Anthraquinone and Its Selected Derivatives

Intra- and intermolecular forces competition was investigated in the 9,10-anthraquinone (1) and its derivatives both in vacuo and in the crystalline phase. The 1,8-dihydroxy-9,10-anthraquinone (2) and 1,8-dinitro-4,5-dihydroxy-anthraquinone (3) contain Resonance-Assisted Hydrogen Bonds (RAHBs). The intramolecular hydrogen bonds properties were studied in the electronic ground and excited states employing Møller-Plesset second-order perturbation theory (MP2), Density Functional Theory (DFT) method in its classical formulation as well as its time-dependent extension (TD-DFT). The proton potential functions were obtained via scanning the OH distance and the dihedral angle related to the OH group rotation. The topological analysis was carried out on the basis of theories of Atoms in Molecules (AIM—molecular topology, properties of critical points, AIM charges) and Electron Localization Function (ELF—2D maps showing bonding patterns, calculation of electron populations in the hydrogen bonds). The Symmetry-Adapted Perturbation Theory (SAPT) was applied for the energy decomposition in the dimers. Finally, Car–Parrinello molecular dynamics (CPMD) simulations were performed to shed light onto bridge protons dynamics upon environmental influence. The vibrational features of the OH stretching were revealed using Fourier transformation of the autocorrelation function of atomic velocity. It was found that the presence of OH and NO2 substituents influenced the geometric and electronic structure of the anthraquinone moiety. The AIM and ELF analyses showed that the quantitative differences between hydrogen bonds properties could be neglected. The bridged protons are localized on the donor side in the electronic ground state, but the Excited-State Intramolecular Proton Transfer (ESIPT) was noticed as a result of the TD-DFT calculations. The hierarchy of interactions determined by SAPT method indicated that weak hydrogen bonds play modifying role in the organization of these crystal structures, but primary ordering factor is dispersion. The CPMD crystalline phase results indicated bridged proton-sharing in the compound 2.     

从分子间作用力看新冠病毒的前世今生

A good way to understand the complex structures and mechanisms of SARS-CoV-2 is from the perspective of chemistry. The basic components, structures, and replication processes of SARS-CoV-2 are described in a firstperson perspective to elucidate the essential role of intermolecular forces in living organisms.