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An electrostatic bond energy model is formulated to fit the enthalpies of formation and dipole moments of the alkanes and chloroalkanes. In this model, the charge distributions are calculated by an electrostatic approach similar to the "MSE" method, and the enthalpy of formation of a molecule is the sum of the bond energy terms plus the electrostatic energy of the interactions between the charges on all atoms. All parameters of this model are obtained by parameterization. The calculated dipole moments for 13 chloroalkanes and enthalpies of formation for 19 alkanes and non-geminal chloroalkanes agree with the determined values very well. To calculate the enthalpies of formation of geminal chloroalkanes, a correction mainly attributed to the van der Waals interactions in the geminal substituted group, about 24 kJ/mol per pair of geminal chlorine atoms, is introduced. 相似文献
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M.L.McGlashan著“Chemical Thermodynamics”(Academic Press,London,1979),已由刘天和、刘芸译,胡日恒审校,中国计量出版社1988年4月出版,新华书店北京发行所发行,各地新华书店经售,该书是目前国际上第一本彻底采用国际单位制(SI)和国际标准化组织(ISO)的国际标准ISO 31/0—13来表达和阐述当代热力学的优秀著作。作者经历的影响,在书中可处处反映出来。M.L. 相似文献
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It has been found that an ordinary reaction calorimeter can be used for the determination of small heat effects (10^-^3 to 10^-^4 C temperature change) by correctly evaluating the Newton's cooling constant K through a reference temperature technique. This technique was applied to the determination of the integral enthalpies of solution of L(+)-aspartic acid and L(+)-glutamic acid in water in the concentration range of 10^-^3 to 10^-^4 mol/kg which were found equal to 25.8+/-0.6 and 25.7+/-0.4kJ/mol respectively (twice standard deviation). No CH2 increment effect has been revealed in the solution enthalpies of these two amino-acids. 相似文献
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In this report, a method for deconvoluting the multi-band spectra of charge-transfer complex is presented and a relation between double-bands is proposed. 49 such spectra in which double-bands appear are calculated. It has been found that the deviation between the calculated and the measured values is less than 3%. The scheme can be extended to deconvolute the CT peaks are used to evaluate the electron affinities of these acceptors. But, the scheme can be used to the π-π charge-transfer complexes. 相似文献
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目前固体比表面积的测定主要是通过测量吸附到固体表面的吸附质的量来实现的。当固体表面积很小时;因为吸附量少,不易测准,精密度差。Groszek用流动微量量热法测量了一些不同种类的固体的比表面积,并与其它方法的数据比较,证明量热法数据可靠、且精密度 相似文献
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微量量热法研究液固吸附正逐渐引起人们的兴趣。本实验室拟开展强化采油中表面活性剂在固体表面吸附机理的研究,装配了一台微量吸附热量计,并用标准化学反应检测其可靠性。研究表面活性剂的吸附规律,需要选用合适的吸附剂。硅胶的组份简单确定,不含干扰离子,表面积足够大,而且它就是油井矿物、粘土等的主要成份,被选为吸附剂样品。但硅胶的表面状态易受制备过程、热处理等因素影响,迄今尚无统一标准的硅胶表面,使用时应表征其表面状态。本文用热失重分析确定硅胶的活化温度、用微量吸附热量计测量了硅胶的浸湿热,并与文献数据进行比较。 相似文献