共查询到20条相似文献，搜索用时 109 毫秒
1.
杨先碧 《青少年科技博览(中学版)》2014,(2):1-2
现在,计算机可以模拟自然界的许多事物。比如,科幻影片中未来世界的场景。同样,用现有技术手段都难以观察到的复杂的化学反应变化,计算朝也可以模拟。这样的研究领域被称为计算化学。 相似文献
2.
孙玉泉 《潍坊教育学院学报》1994,(2)
有机化学反应千差万别 很复杂,但有机化合物在化学反应过程中却都需要经过活性中间体这一阶段.活性中间体的生成与转化是研究有机化学反应历程的重要环节.本文仅对其中的负碳离子这一活性中间体从各个方面进行探讨. 相似文献
3.
化学反应的进行缘于分子间不断产生的随机有效碰撞.这种碰撞的随机性就为用MonteCarlo方法来模拟反应动力学过程提供了可能.依此,在Matlab环境下设计了一种用MonteCarlo方法来模拟化学反应动力学的算法.通过对反应实例的模拟,结果表明,MonteCarlo方法不仅与龙格库塔法一样均能对已建立动力学方程的组分进行较好模拟,而且对动力学方程欠缺组分的模拟也是有效的. 相似文献
4.
教学目标 :1.理解和掌握化学反应中反应物的物质的量对化学反应的重要性。2 .在探究化学反应与物质的量的关系的过程中对学生进行科学方法的教育。3 .学会运用物质的量与化学反应的知识来认识和解决问题 ,并将其与工业生产实践相联系。教学重点 :1.化学反应中反应物的物质的量和反应历程及产物的关系。2 .研究化学反应中反应物的物质的量的关系的科学方法。教学模式 :指导———完善模式和引导———探究模式相结合的复习课。教学手段 :1.用Ｐｏｗｅｒｐｏｉｎｔ显示板书及有关图片。2 .用自编动画软件模拟反应中的微观情况。3 .用实物投影… 相似文献
5.
针对复杂化学反应的配平问题,文章在综合各类化学反应方程式配平方法优点的基础上,给出一种通过"分解"反应物或生成物配平化学反应的方法.结果表明,与传统配平方法相比.该方法具有不需要掌握化合价和电子转移的情况.也不需要处理复杂数学运算的特点.且该方法对化学反应方程式的配平方法是一个有益的补充,对理解化学反应的本质也有一定的... 相似文献
6.
刘敬 《中学化学教学参考》2004,(3):41-42
涉及到化学反应的计算题千变万化，但只要我们抓住化学反应的实质，那么不论怎么复杂的计算都可化繁为简，迎刃而解。特别是终态分析法，在分析清楚化学反应的过程后，只需考虑反应的最终结果，不拘泥于细枝末节，从大处着手，借助守恒思维，往往能出奇制胜，有令人惊叹的效果。 相似文献
7.
8.
9.
以UbD理论为支撑,对“化学反应速率”一课进行教学设计。研究表明：基于UbD理论的教学设计有助于达成“教、学、评”一致性,融合PhET虚拟仿真实验平台模拟的化学反应,能让学生更主动地融入学习,提高学生联系和分析宏观现象与微观可视化的能力,促进学科核心素养的落地。 相似文献
10.
运用超声方法对丙酮碘化反应和丙酮与高猛酸钾氧化反应进行了研究，实验表明：超声空化作用对丙酮氧化具有正催化作用，这是由于声波能形成局部高温高压，导致自由基，声波使键能共振等一些特性，不仅能够加快某些化学反应的速度，而且能够使某些在通常情况下不发生的化学反应在超声波的作用下进行，此外实验用光谱吸收法来测定化学反应的进程。 相似文献
11.
大多数有机化学反应是在溶剂中进行,欲深入研究有机反应的平衡与速率,溶剂效应不容忽略。但由于溶质——溶剂作用的复杂性,目前仍无严格的定性定量理论与公式。本文在此领域内以若干简单反应为模型探讨了溶剂效应对反应平衡和反应速度的影响。 相似文献
12.
Pallavi Bhattacharyya 《Resonance》2012,17(7):635-652
Henry Eyring is most well-known as the proponent of the activated complex (transition state) theory for chemical reactions. He was also the one to construct the first Potential Energy Surface along with Michael Polanyi. Apart from his exemplary work in chemical kinetics, the plethora of problems he engaged in establish his versatile genius. Evaluation of dipole moments in complex molecules, one-electron theory for optical activity, conformation changes in proteins, deformation kinetics in materials are some of the fields where his contributions have been immensely significant. He was a prolific writer and authored more than 600 articles and 10 scientific volumes. This article will discuss the contributions of Henry Eyring. 相似文献
13.
微波加热在有机反应中的应用 总被引：2，自引：0，他引：2
在化学反应中,大多数反应都必须在一定的温度和一定的时间范围内才能完成,特别是一些有机化合物的合成反应,如反应温度、时间掌握不当,则副反应产物将占的比例较大,从而使产品产率降低.为此作者利用微波加热的方法来提高产率,并且与常规加热方法进行对比实验,微波加热有节省时间、节省能源、提取效率高、安全的优点等. 相似文献
14.
从热力学角度分析了固相反应的吉布斯自由能变,印证了固相反应一旦发生,便能进行到底的结论.并且,探讨了固相反应在化学合成和保护环境等方面较液相反应具有非常明显的优势. 相似文献
15.
Dynamic visualizations can make unseen phenomena such as chemical reactions visible but students need guidance to benefit from them. This study explores the value of generating drawings versus selecting among alternatives to guide students to learn chemical reactions from a dynamic visualization of hydrogen combustion as part of an online inquiry unit. In prior research, generation has been more successful than selection in helping students distinguish among ideas to learn complex topics. However, selecting among perplexing alternatives may motivate learners to distinguish among ideas they might otherwise neglect. To test the value of selection for helping students distinguish ideas, this study contrasted complex selection (involving normative as well as non-normative ideas identified in prior research) from typical selection (involving images from the visualization). Results showed that all conditions improved student understanding and that typical selection was less effective than generation while complex selection was as successful as generation. In both generation and complex selection students revisited the visualization while learning, whereas revisiting was rare in typical selection. These results support the idea that distinguishing among common non-normative ideas is more valuable than distinguishing among images from the visualization. In addition, for students with low prior knowledge, both generation and complex selection had some advantages. Overall, the results suggest that students learning from complex visualizations could benefit from a combination of complex selection and generation. 相似文献
16.
吴萍 《扬州职业大学学报》2002,6(2):50-53
给出了有机化合物酸碱性的定性判断方法，可通过比较负离子的稳定性来判断酸性强弱，分析中心原子电子云密度大小及空间效应来判断碱性强弱，运用有机物的碱酸性可在有机化学中分离化合物，比较物质反应活性的差异等。 相似文献
17.
Excel在化工数据及模型参数拟合中的应用 总被引：1，自引：0，他引：1
运用Excel的回归分析功能，对化工实验数据进行处理，可以满足在化工数据与模型参数拟合中遇到的复杂计算问题。通过实例说明该方法的实用性及有效性。 相似文献
18.
This study explores the impact of asking middle school students to generate drawings of their ideas about chemical reactions on integrated understanding. Students explored atomic interactions during hydrogen combustion using a dynamic visualization. The generation group drew their ideas about how the reaction takes place at the molecular level. The interaction group conducted multiple experiments with the visualization by varying the amount of energy provided to ignite the reaction. The generation group integrated more ideas about chemical reactions and made more precise interpretations of the visualization than the interaction group. Embedded assessments show that generation motivated students to interpret the visualization carefully and led to more productive explanations about ideas represented in the dynamic visualization. In contrast, the interaction group was less successful in linking the visualization to underlying concepts and observable phenomena and wrote less detailed explanations. The study suggests that drawing is a promising way to help students interpret complex visualizations and integrate information. © 2011 Wiley Periodicals, Inc. J Res Sci Teach 48: 1177–1198, 2011 相似文献
19.
以硅烯为重要反应中间体的硅烯化学越来越引起人们的重视,本文选取含N杂环的硅烯稳定结构作为基本单元,探讨通过S i-O键合形成的低聚体的电子结构特性.采用Gaussian03程序包中的AM1方法,计算了几种模型的能级结构、电荷分布及激发态性质,并对计算结果从微观机理上进行了分析. 相似文献
20.
Quantum chemical simulation was used to investigate the catalytic mechanism of Na/K on NO-char heterogeneous reactions during the coal reburning process. Both NO-char and NO-Na/K reactions were considered as three-step processes in this calculation. Based on geometry optimizations made using the UB3LYP/6-31G（d） method, the activation energies of NO-char and NO-Na/K reactions were calculated using the QCISD（T）/6-311G（d, p） method; Results showed that the activation energy of the NO-Na/K reaction （107.9/82.0 kJ/mol） was much lower than that of the NO-char reaction （245.1 kJ/mol）. The reactions of NaO/KO and Na2O/K2O reduced by char were also studied, and their thermodynamics were calculated using the UB3LYP/6-31G（d） method; Results showed that both Na and K can be refreshed easily and rapidly by char at high temperature during the coal reburning process. Based on the calculations and analyses, the catalytic mechanism of Na/K on NO-char heterogeneous reactions during the coal reburning process was clarified. 相似文献