Silver Oxide: Heat Capacity from 13 to 300°K., Entropy, Heat of Solution, and Heat and Free Energy of Formation. The Heat of Formation and Entropy of Silver Ion

1937 ◽  
Vol 59 (12) ◽  
pp. 2633-2639 ◽  
Author(s):  
Kenneth S. Pitzer ◽  
Wendell V. Smith
Keyword(s):  
Heat Capacity ◽  
Free Energy ◽  
Silver Oxide ◽  
Heat Of Formation ◽  
Silver Ion ◽  
Heat Of Solution ◽  
Free Energy Of Formation ◽  
Energy Of Formation

Heat Capacity, Entropy, and Free Energy of Rubber Hydrocarbon

1936 ◽  
Vol 9 (2) ◽  
pp. 264-274 ◽  
Author(s):  
Norman Bekkedahl ◽  
Harry Matheson
Keyword(s):  
Heat Capacity ◽  
Free Energy ◽  
Heat Of Formation ◽  
The Third ◽  
Free Energy Of Formation ◽  
Third Law Of Thermodynamics ◽  
Third Law ◽  
Lower Temperature ◽  
Energy Of Formation

Abstract The best method for obtaining the free energy of formation of rubber is by making use of the third law of thermodynamics. This makes necessary the determination of heat-capacity values of rubber from room temperature down to temperatures sufficiently low to apply an empirical formula for obtaining the values below this lower temperature. From these heat-capacity values the entropy may be obtained. Then from this latter value, along with the entropy values of carbon (graphite) and gaseous hydrogen and the heat of formation of rubber, a reliable value for the free energy of formation of rubber may be calculated. Several investigators have previously determined the heat capacities of rubber, but their observations were not made at temperatures sufficiently low to permit accurate extrapolation to the absolute zero in order to apply the third law. Furthermore, in the previous work the possibility that rubber at low temperatures might exist either as a metastable amorphous form or as a crystalline form was not clearly recognized. In the present investigation the aim was not only to extend the temperature range but also to obtain data of a higher order of accuracy than that previously reported.

The tetrahedral intermediate from the hydration of N-methylformanilide

1993 ◽  
Vol 71 (12) ◽  
pp. 2109-2122 ◽  
Author(s):  
J. Peter Guthrie ◽  
Jonathan Barker ◽  
Patricia A. Cullimore ◽  
Jinqiao Lu ◽  
David C. Pike
Keyword(s):  
Aqueous Solution ◽  
Free Energy ◽  
Dimethyl Acetal ◽  
Heat Of Formation ◽  
Basic Solution ◽  
Tetrahedral Intermediate ◽  
Rate Determining Step ◽  
Free Energy Of Formation ◽  
Hydrolysis Of ◽  
Energy Of Formation

Heats of hydrolysis of N-methylformanilide dimethyl acetal have been measured in basic solution. The heat of formation of N-methylformanilide was obtained by determining the equilibrium constant in aqueous solution for its formation from formic acid and N-methylaniline as a function of temperature:[Formula: see text]. These data permit the calculation of the heat of formation of N-methylformanilide dimethyl acetal, [Formula: see text]. The free energy of formation of the tetrahedral intermediate in the hydrolysis of N-methylformanilide was calculated by methods we have previously reported. Consideration of the energetics of the intermediates and the known rates of reaction leads to the conclusion that the rate-determining step for alkaline hydrolysis is cleavage of the C—N bond.

THERMODYNAMIC PROPERTIES OF SYNTHETIC BASIC ALUMINITE [Al4(OH)10SO4∙5H2O] FROM SOLUBILITY DATA

1980 ◽  
Vol 60 (2) ◽  
pp. 381-384 ◽  
Author(s):  
S. SHAH SINGH
Keyword(s):  
Free Energy ◽  
Standard Free Energy ◽  
Entropy Change ◽  
Heat Of Formation ◽  
Standard Free Energy Change ◽  
Kcal Mole ◽  
Free Energy Of Formation ◽  
Equilibrium Data ◽  
Solubility Equilibrium ◽  
Energy Of Formation

From the solubility equilibrium data of basic aluminite at three temperatures, the standard free energy change (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) were determined as 160.02 kcal∙mole−1, 65.48 kcal∙mole−1 and 317.1 cal∙deg−1]mole−1, respectively. From these values the free energy of formation (ΔGf°) and the heat of formation (ΔHf°) of basic aluminite was also computed and was 1465.25 kcal∙mole−1 and 1682.08 kcal∙mole−1, respectively.

scholarly journals Isomers of (L)-Diiodotyrosine - A DFT Treatise

2021 ◽  
pp. 347-361
Author(s):  
Lemi Türker
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Hydrogen Bonding ◽  
Quantum Chemical ◽  
Density Functional ◽  
Heat Of Formation ◽  
Functional Theory ◽  
Free Energy Of Formation ◽  
Ionic Forms ◽  
Energy Of Formation

(L)-Diiodotyrosine isomers are considered within the realm of density functional theory at the level of B3LYP/6-311+G(d,p). Their zwitter ionic forms are considered as well. All the structures are electronically stable, have exothermic heat of formation and favorable Gibbs free energy of formation values. Within the limitations of the method the zwitter ionic forms are not different from the corresponding parent structures in the vacuum conditions and no hydrogen bonding seems to exist between the NH2 and COOH groups. Some structural, quantum chemical and spectral data have been collected and discussed.

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