The Thermodynamic Properties of Technetium and Rhenium Compounds. VII. Heats of Formation of Rhenium Trichloride and Rhenium Tribromide. Free Energies and Entropies1,2

1960 ◽  
Vol 82 (9) ◽  
pp. 2111-2113 ◽  
Author(s):  
J. P. King ◽  
J. W. Cobble
Keyword(s):  
Thermodynamic Properties ◽  
Heats Of Formation ◽  
Free Energies

Thermochemistry of biscyclopentadienyl metal compounds

1967 ◽  
Vol 20 (10) ◽  
pp. 2059 ◽  
Author(s):  
AG Turnbull
Keyword(s):  
Thermal Decomposition ◽  
Thermodynamic Properties ◽  
Ideal Gas ◽  
Heats Of Formation ◽  
Free Energies ◽  
Metal Compounds ◽  
Temperature Range ◽  
Thermodynamic Feasibility

Standard free energies of formation for the temperature range 298- 1000�K are calculated for C5H5, C5H6, and the biscyclopentadienyl compounds of iron, ruthenium, nickel, and magnesium by combining reported heats of formation at 298�K with calculated ideal-gas thermodynamic properties. The results are used to predict the thermodynamic feasibility of three types of reactions-the formation of biscyclopentadienyl metal compounds, their thermal decomposition, and their reduction with hydrogen. It is shown that the predictions are in agreement with qualitative chemical observations.

A Theoretical Study of Substituted Stepwise Fluorinated Cyclopropanone Keto-Enol System

2003 ◽  
Vol 58 (12) ◽  
pp. 749-755
Author(s):  
Abdullah El-Alali ◽  
Ali A. Marashdeh ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Study ◽  
Dipole Moments ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Isodesmic Reactions ◽  
Orbital Energies ◽  
Substantial Concentration ◽  
Homo Lumo ◽  
Complete Optimization

MINDO-Forces calculations have been performed with complete optimization of the geometries on stepwise fluorinated cyclopropanones and their enols. Increase in the number of fluorine atoms causes destabilization of cyclopropanone. Perfluorinated enol was found to be present in substantial concentration, as was mentioned in previous work. This is supported by calculations of Gibbs free energies and isodesmic reactions. Geometrical parameters, heats of formation, electron densities, dipole moments and orbital energies (HOMO-LUMO) are reported.

MINDO-Forces Study on Substituted Nitromethane ⇋ aci-Nitromethane Tautomerism

2005 ◽  
Vol 60 (1-2) ◽  
pp. 47-53
Author(s):  
Bareehan M. Salim ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Calculations ◽  
Geometry Optimization ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Electron Densities ◽  
Isodesmic Reactions ◽  
Complete Geometry Optimization

MINDO-Forces calculations with complete geometry optimization have been performed on nitromethane, aci-nitromethane and X-substituted nitromethane and aci-nitromethane (X = F, OH, NH2, CH3, CN, CF3, NO2, CHO). It is found that nitromethane is more stable than aci-nitromethane by 9.337 kcal/mol. This agrees with theoretical calculations. Thermodynamically, substituted aci-nitro tautomers are more stable than the corresponding nitromethane, except in case of the substituent F. Geometrical parameters, heats of formation, electron densities, Gibbs free energies and isodesmic reactions are reported.

Thermodynamic properties of the binary molten salt systems, PbBr2-KBr, PbBr2-RbBr and PbBr2-CsBr, by measurement of the electromotive forces of galvanic cells

1981 ◽  
Vol 34 (3) ◽  
pp. 479 ◽  
Author(s):  
H Bloom ◽  
MS White
Keyword(s):  
Thermodynamic Properties ◽  
Molten Salt ◽  
Activity Coefficients ◽  
Molten Salts ◽  
Free Energies ◽  
Complex Ions ◽  
Galvanic Cells ◽  
Salt Systems

The electromotive forces of galvanic cells for the formation of PbBr2 in the molten binary salt systems, PbBr2-KBr, PbBr2,-RbBr and PbBr2-CsBr, have been measured. Activities, activity coefficients and partial molar free energies have been calculated for each component of the three systems. Integral free energies of mixing have also been calculated. Various models of mixing of molten salts have been applied to the results. The systems contain complex ions, probably mixtures of PbBr42-, PbBr64- with some PbBr3-.

Calculation on the Free Energy of Mixing of some Silane Systems

2011 ◽  
Vol 391-392 ◽  
pp. 1017-1021
Author(s):  
Ru Zhang ◽  
Yan Fen Wu ◽  
Ping Hu
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Activity Coefficients ◽  
Influence Factors ◽  
Critical Parameters ◽  
Model Parameters ◽  
Free Energies ◽  
Wilson Model ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing

Six binary silane systems were chosen to calculate the activity coefficients (γ) and free energies of mixing (ΔGm). These systems included: methyldichlorosilane + methyltrichlorosilane, methyldichlorosilane + methylvinyldichlorosilane, methyldichlorosilane + toluene, methyltrichlorosilane + methylvinyldichlorosilane, methyltrichlorosilane + toluene, methylvinyldichlorosilane + toluene. Based on the Antoine constants, critical parameters of the pure components and Wilson model parameters, γ and ΔGmwere calculated. The influence factors of these thermodynamic properties were also discussed.

Redox Systems

1993 ◽  
Author(s):  
Greg M. Anderson ◽  
David A. Crerar
Keyword(s):  
Thermodynamic Properties ◽  
Oxidation State ◽  
Point Of View ◽  
Single Variable ◽  
Free Energies ◽  
Chemical Behavior ◽  
Redox Systems ◽  
Sufficient Detail ◽  
Electron Distributions ◽  
Nuclear Processes

Up until this point we have dealt with familiar intensive variables such as temperature, pressure, density, and molar thermodynamic properties (molar entropies, free energies, and so on). There exists another, equally important intensive variable that we have used implicitly, but have not yet discussed in sufficient detail—the oxidation state of a system. This involves concepts and applications so useful to Earth scientists that we devote a complete chapter to this single variable. Except for nuclear processes, most chemical behavior is determined by electron distributions and interactions. From this point of view, the oxidation state of an atom is among the most fundamental of all its properties. Most elements can exist in multiple valences with each state usually displaying quite different behavior from the others. As an example, consider the element sulfur.

Interactions between cations and sugars. III. Free energies, enthalpies, and entropies of association of Ca2+, Sr2+, Ba2+, La3+, Gd3+ with D-ribose in water at 25 °C

1987 ◽  
Vol 65 (11) ◽  
pp. 2656-2660 ◽  
Author(s):  
Alfredo Maestre Alvarez ◽  
Nicole Morel-Desrosiers ◽  
Jean-Pierre Morel
Keyword(s):  
Thermodynamic Properties ◽  
Aqueous Solutions ◽  
Equilibrium Constant ◽  
The Other ◽  
Free Energies ◽  
Mean Values ◽  
Enthalpies Of Transfer ◽  
Other Hand ◽  
Solutions Of Electrolytes

The standard enthalpies of transfer of ribose and arabinose from water to aqueous solutions of electrolytes (CaCl2, SrCl2, BaCl2, LaCl3, and GdCl3) have been measured at 25 °C. A method is described to calculate from these data the equilibrium constant and the enthalpy for the association between the cations and the complexing isomers of ribose. Mean values relative to these isomers are given: the constants vary from 2.0 to 4.3 and the enthalpies from −5.9 to −17.9 kJ mol−1 for the different cations studied. The thermodynamic properties of association are not related to the size nor to the charge of the complexed cation in a simple way. On the other hand, the enthalpies of reaction are linearly correlated to the entropies of reaction.

THE HEAT OF WETTING OF SILK FIBROIN BY WATER

1955 ◽  
Vol 33 (5) ◽  
pp. 904-912 ◽  
Author(s):  
H. Brian Dunford ◽  
John L. Morrison
Keyword(s):  
Water Vapor ◽  
Adsorption Isotherm ◽  
Thermodynamic Properties ◽  
Silk Fibroin ◽  
Adsorption Process ◽  
Film Formation ◽  
Adsorbed Water ◽  
Water Vapor Adsorption ◽  
Free Energies ◽  
Heat Of Wetting

The heats of wetting by water of silk fibroin initially containing various amounts of adsorbed and desorbed water have been measured. These measurements along with the water vapor adsorption isotherm of Hutton and Gartside have been used to calculate the integral and differential heats, free energies, and entropies of adsorption. In contrast with cellulose, silk containing desorbed water evolves less heat than that containing adsorbed water. This fact suggests that any contribution by a heat of swelling term is very small for silk fibroin, so that the calculated thermodynamic properties probably can be assigned almost entirely to the adsorption process. The changes in the heats and entropies of adsorption appear to parallel the sequence of changes in film formation as revealed by surface area calculations.

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