共查询到20条相似文献,搜索用时 15 毫秒
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从知识考古学的视角,分析当前“课堂中的化学平衡”的历史根源。作为简化的学科知识,“教材中的化学平衡”不仅划定了知识的边界,而且内隐了知识的结构;作为演进的理解表现,“高考中的化学平衡”逐步形成了稳定的考查角度和方式。作为实然的教学内容,“课堂中的化学平衡”是多元主体社会协商形成的“共识”,具有区域性特征,包含特定的话语,是一种高度依赖于学校情境的工具化、条件化了的知识。 相似文献
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分析了“化学平衡常数”的教材内容和相关教学设计,针对实际教学中存在的2个问题:简化的数据探究难以让学生体会到科学研究的复杂性;纯粹的知识性教学难以体现科学知识的价值和意义。提出在教学中融合化学史和数据探究,能帮助学生全面深入地理解概念,促进学生进一步认识科学本质和学科价值。 相似文献
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Victor A. Snyder 《Journal of mathematical chemistry》2006,40(2):119-134
The classical thermodynamic treatment of chemical equilibria in closed systems is founded on theoretical formulations by J.W. Gibbs and Th. De Donder. These two theories represent mathematically equivalent energy variation problems, related to each other through a mass variable transformation analogous to coordinate transformations in mechanics. Associated with the change in mass variables, chemical potentials of reactive substances are defined differently in the two theories, and are subject to different sets of constraints. Traditionally, the two sets of constraints have been merged into one, by assuming that the chemical potential represents the same variable in both theories, an assumption that is formally inconsistent with the difference in chemical potential definitions. Merging of constraints is still possible if chemical potentials remain invariant in value as a manifestation of symmetry under a Gibbs – De Donder mass transformation, but such symmetry has not been investigated. Here we demonstrate chemical potential invariance by reformulating De Donder’s theory using Lagrange multipliers, and combining the resulting constraints on chemical potentials with the classical Gibbs constraints, in a phase equilibration thought experiment. A new form of the Gibbs–Duhem (GD) relation is derived in the De Donder mass system. Comparing this relation to the classical GD equation in Gibbs’ component framework, subject to chemical potential invariance, directly yields the linear operator mapping the De Donder mass variables onto the set of Gibbs component masses. Results are illustrated for a simple ion exchange reaction, in the process solving the longstanding problem of determining solid exchanger activities in ion exchanging mixtures. It is pointed out that, even though the Gibbs and De Donder formulations are mathematically equivalent, the formal structure of De Donder’s theory allows a more explicit and systematic treatment of constraints, and also defines chemical masses in a form more naturally adapted to typical experimental measurements. 相似文献
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Equilibrium adsorption of binary mixtures of gases by zeolites and the state of the adsorption phase
A method for analyzing the state of the adsorption phase was developed on the basis of statistical thermodynamics for the
case of equilibrium adsorption of binary gaseous mixtures. The procedure for treating experimental data to determine the Helmholtz
energy and other thermodynamic functions of a mixture of molecules occluded within zeolite cavities was proposed. A measure
of ideal behavior of a mixture of a small number of molecules in the micropore was formulated; in the asymptotic limit such
a behavior leads to the Raoult law and to assumption of the validity of the Raoult law when moving along the line of constant
value of the Gibbs integral in the ideal adsorption solution theory.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1927–1932, October, 1998. 相似文献
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关于稳定单变度曲线自动判别的一种简便的普适性方法 总被引:3,自引:0,他引:3
无变度点周围各单变度曲线稳定性的自动判别,是多体系稳定平衡相图计算机成图理论中十分关键而棘手的问题。它既令化学家感兴趣,更为地质地球化学家、冶金学家、材料学家所关注。在这方面,已有不少学者做过探讨,其基本依据是“等温等压下达到平衡时体系的Gibbs自... 相似文献
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利用平衡移动原理可以定性判断浓度对电极电势的影响。在改变除电对以外离子的浓度、改变电对其中1种离子的浓度、同时改变电对本身2种离子的浓度的3种情况下,能斯特方程和该法均可得到相同的结论,但后者更简单。 相似文献
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高效毛细管电泳分离中的化学平衡 总被引:2,自引:0,他引:2
在高效毛细管电泳(HPCE)中缓冲对分离有重要影响,缓冲中的化学平衡决定了待测组分的存在状态或形态,从而决定了组分的电泳尚度,淌度的差异是HPCE分离之基础,因此,溶液化学平衡在HPCE分离中起着重要作用,本文综述了电泳淌度,HPCE分离与化学平衡的关系,并要介绍了电泳淌度与酸碱平衡,络合平衡的关系,从化学平衡的角度,讨论了酸碱性化合物,金属离子,对映异构体等几大类化合物的HPCE分离。 相似文献
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基于可信度在概念转变中的重要性,介绍了注重证据与概念匹配关系的证据模型链(MEL)教学支架,说明了它在支持概念可信度重新评估、促进概念转变教学有效完成中的作用。通过分析MEL支架的构成要素及呈现形式,开发了适用于化学概念转变教学的课堂教学模式,并以容易产生相异构想的典型主题“化学平衡的动态性”为教学设计案例,对基于MEL的概念转变教学模式付诸实践并予以说明。 相似文献
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基于认识方式有关理论及高中生化学平衡认识模型,分析高中生在化学平衡从必修到选修的认识发展情况,进行促进学生认识发展的教学设计,实施课堂教学,并对比传统以知识获得为主的课堂教学,通过学生实际认识测查数据说明促进学生认识发展型教学优于传统教学。建议教师充分挖掘化学平衡常数的认识功能与价值,围绕化学平衡常数开展课堂教学,建立和发展学生对化学平衡的认识。 相似文献
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利用安卓智能手机的CMOS传感器并配合安卓手机软件Color Grab来获取不同编号试管中FeCl3溶液的L*,a*,b*值,并将相应数据导入到智能手机的WPS Office中处理后得到相应的色差值,通过比较色差值大小来探究浓度对化学平衡的影响,取得了良好的效果。 相似文献