Results 251 to 260 of about 2,123,596 (289)

A DFT study on the enthalpies of thermite reactions and enthalpies of formation of metal composite oxide

Chemical Physics, 2018
Abstract The standard thermite reaction enthalpies (ΔrHmθ) for seven metal oxides were theoretically analyzed using density functional theory (DFT) under five different functional levels, and the results were compared with experimental values. Through the comparison of the linear fitting constants, mean error and root mean square error, the Perdew ...
Yu-ying Zhang, Meng-jie Wang, Chun-ran Chang, Kang-zhen Xu, Hai-xia Ma, Feng-qi Zhao   +5 more
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Enthalpy versus Entropy in Chlorocarbene/Alkene Addition Reactions

Journal of the American Chemical Society, 2008
We report the first measured activation parameters for the additions of CCl2 and CClF to simple alkenes and demonstrate the existence of enthalpic barriers for CCl2 additions to cyclohexene and 1-hexene. With these two alkenes, additions of PhCCl are "dominated" by entropic contributions to deltaG++ and additions of CCl2 display comparable ...
Robert A, Moss, Lei, Wang, Min, Zhang, Christopher, Skalit, Karsten, Krogh-Jespersen   +4 more
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Activation and Reaction Volumes and Their Correlations with the Entropy and Enthalpy Parameters

Journal of Chemical & Engineering Data, 2015
© 2015 American Chemical Society. Data for the enthalpies, entropies, and volumes of 271 liquid compounds at standard conditions as well as those for 103 isomerization and decomposition reactions have been collected and compared. It was observed that the values of liquid molar volumes are proportional to the standard molar entropies of these compounds (
Kornilov D., Kiselev V.
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The Reaction of Serpins with Proteinases Involves Important Enthalpy Changes

Biochemistry, 2001
When active serpins are proteolytically inactivated in a substrate-like reaction, they undergo an important structural transition with a resultant increase in their conformational stability. We have used microcalorimetry to show that this conformational alteration is accompanied by an important enthalpy change.
C, Boudier, J G, Bieth
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Calculating Enthalpy of Reaction by a Matrix Method

Journal of Chemical Education, 2000
A matrix representation method is suggested to calculate for the enthalpies of chemical reactions from given thermochemical equations using the relation ns = nnet, where n, s, and nnet represent the stoichiometric number matrices of the given reactions, the path matrix, and the stoichiometric number matrix of the equation to be solved.
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Gas-Phase Enthalpies of Formation and Enthalpies of Sublimation of Amino Acids Based on Isodesmic Reaction Calculations

The Journal of Physical Chemistry A, 2014
Accurate gas-phase enthalpies of formation (ΔfH298°) of 20 common α-amino acids, seven uncommon amino acids, and three small peptides were calculated by combining G4 theory calculations with an isodesmic reaction approach. The internal consistency over a set of ΔfH298°(g) values was achieved by sequential adjustment of their values through the ...
Olga V, Dorofeeva, Oxana N, Ryzhova
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Enthalpies of reactions at the metal oxide/aqueous interface

Langmuir, 1993
A detailed thermodynamic analysis of simultaneous surface reactions is presented, with a special emphasis on the definition of standard enthalpies. An experimental study of the surface reactions at the anatase/water interface is also reported. Generally, the reaction enthalpy is defined as the ratio of the reaction heat and its extent.
Žalac, Suzana, Štefanić, Goran, Kallay, Nikola   +2 more
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Reaction enthalpies as selection criteria for tribological coatings

physica status solidi (b), 2003
AbstractA wide range of coatings are used for a variety of applications. Selection criteria for these coatings include coating‐substrate adhesion, hardness, melting temperature, coefficient of thermal expansion mismatch, corrosion resistance, and cost. A factor often ignored is the possibility of reaction between the coating and the other surface which
N. Ooi, James B. Adams, Uttam Singisetti
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Calculating Enthalpy of Reaction from Bond Dissociation Energy

2020
The Purpose of The Exercise In my experience, it is pretty rare for an organic chemist to carry out one of these calculations. However, they will look at a reaction and intuitively know whether it is likely to be endothermic or exothermic... They can...
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Enthalpy Changes for Reactions Involving Anionic Species

2020
A Strange Statement The two statements below appear to be direct contradictions. How can they possibly both be correct? The devil is in the details. Addition of HBr across an alkene can be exothermic. Elimination of HBr to form an alkene can also be exothermic....
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