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压强是一个物理概念,化学实验中的喷泉实验、气密性检验、排液量气、倒吸实验等均与气体压强有关。对中学化学实验中的气压问题做了归纳与整合,并以相应的高考题例证。 相似文献
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岳金辉同志在“压强对化学反应速度影响的实验”一文中,用简单的具支试管和注射器做二氧化硫与硫化氢反应的实验来说明压强对反应速度的影响,看后很受启发。 相似文献
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《化学教育》1987年第3期第35页,介绍了张克梅同志的“也谈压强对化学反应速度影响的实验”一文。笔者读后,并经重复实验,认为文中的实验原理、实验现象和结论均存在某些问题,现将自己的看法提出来和有关同志商榷。一、关于实验原理原文中的实验原理是在等容、等温和参加反应的气体体积恒定的条件下,通过改变不参加反应的空气的体积而使体系压强改变的方法来说明压强改变对反应速度的影响的。 相似文献
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利用自制木制固定器、注射器等设计实验装置,借助压强传感器展示压强对"2NO2?N2O4"平衡体系的影响,实验操作简单,直观地展现了平衡移动过程,对于学生学习化学平衡尤其是理解勒夏特列原理有很大的帮助。 相似文献
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统编高中化学教材关于压强对化学平衡移动的影响,选取了在注射器中做N2O4和NO2混和气体的颜色随压强改变的实验.对于这个实验选择得是否合适,实验现象与教材所写是否相符,说法不少.但经过实践,我认为这个实验是可以说明问题的.实验现象是否与教材所说相符,关键在于是从注射器的顶面观察还是从侧面观察. 相似文献
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利用真空保鲜盒作为测定气体摩尔体积实验的实验装置,并借助智能手机的气压传感器通过手机软件Phyphox来测定实验装置内的压强变化,以此来测定标况下气体摩尔体积。实验结果表明改进后的实验取得了良好的效果,并且改进后的方法更易于学生动手操作。 相似文献
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关于“压强对化学平衡影响”实验的改进 总被引:2,自引:0,他引:2
压强对化学平衡影响实验,在刊物上已有不少文章提出了改进意见。但是还不够理想,本人做了多次实验对此提一点改进的意见和措施。 相似文献
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Mustafa R. Ibrahim Zacharia A. Fataftah Paul von Ragu Schleyer Peter D. Stout 《Journal of computational chemistry》1987,8(8):1131-1138
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases. 相似文献
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由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1989,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988. 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1988,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae. 相似文献
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Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin
E. I. Kapinus V. A. Ganzha B. M. Dzhagarov E. I. Sagun V. B. Pavlenko 《Theoretical and Experimental Chemistry》1989,25(2):146-151
The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989. 相似文献
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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