Gibbs reaction

In the literature tetrathiosulfuranes have been discussed as possible intermediates in the thermal decomposition of sulfanes and other polysulfur compounds. High-level ab initio MO calculations have in fact revealed that such species are local minima on the potential energy hypersurface [34]. However, recent results show that both the Gibbs reaction energies as well as the activation enthalpies for reactions of the type... 

The mechanism of the Gibbs reaction has been investigated." It has been concluded that A-chloroimine radical anion (80), generated in a single-electron transfer... 

Gibbs reaction energy(or maximum work lTg)AG = -702kJ/mol = 1.21 eV... 

Butylated hydroxyanisole Gibbs reaction 0.5-400 Amplification method using a DA detector... 

In Eqs. (127) and (128) /fa is the equilibrium constants of the chemical reaction and and are the activities at equilibrium concentrations of the reactants. Using the concept of standard reaction enthalpies, standard Gibbs reaction energies, and standard entropies (Section III), the quantities h (P T) can be calculated with the help of tabulated standard values (at 25°C and 1 atm) and Cp or U functions. Phase transitions on the path of integration must... 

With the knowledge of the Gibbs reaction enthalpy AG°, the standard decomposition... 

The mechanism of the Gibbs reaction, an assay for phenols using, e.g., 2,6-dichlorobenzoquinone iV-chloroimine, has been probed for a wide range of imines and phenols. The first step of single-electron transfer to produce the iV-chloroimine radical anion is followed by a mechanistic divergence into three routes, depending on the reactivity of the pair of reactants. 

Gibbs-Helmholtz equation This equation relates the heats and free energy changes which occur during a chemical reaction. For a reaction carried out at constant pressure... 

For analysing equilibrium solvent effects on reaction rates it is connnon to use the thennodynamic fomuilation of TST and to relate observed solvent-mduced changes in the rate coefficient to variations in Gibbs free-energy differences between solvated reactant and transition states with respect to some reference state. Starting from the simple one-dimensional expression for the TST rate coefficient of a unimolecular reaction a— r... 

Kirkwood generalized the Onsager reaction field method to arbitrary charge distributions and, for a spherical cavity, obtained the Gibbs free energy of solvation in tenns of a miiltipole expansion of the electrostatic field generated by the charge distribution [12, 1 3]... 

The most important themiodynamic property of a substance is the standard Gibbs energy of fomiation as a fimetion of temperature as this infomiation allows equilibrium constants for chemical reactions to be calculated. The standard Gibbs energy of fomiation A G° at 298.15 K can be derived from the enthalpy of fomiation AfT° at 298.15 K and the standard entropy AS° at 298.15 K from... 

Gibbs values and the effective electrode potential follows the Nemst equation (see section C2.11). For the oxidation (anodic) reaction, the potential (E ) of the Nemst equation can be written as ... 

This shows that Eqs. (1) and 2) are basically relationships between the Gibbs free energies of the reactions under consideration, and explains why such relationships have been termed linear free energy relationships (LEER). 

Having calculated the standai d values AyW and S" foi the participants in a chemical reaction, the obvious next step is to calculate the standard Gibbs free energy change of reaction A G and the equilibrium constant from... 

As has been noted above, there is no gross change in the mechanism of nitration of PhNH3+ down to 82 % sulphuric acid. The increase in o- andp-substitution at lower acidities has been attributed differential salt effects upon nitration at the individual positions. The two sets of partial rate factors quoted for PhNH3+ in table 9.3 show the effect of the substituent on the Gibbs function of activation at the m- and -positions to be roughly equal for reaction in 98 % sulphuric acid, and about 28 % greater at the -position in 82 % sulphuric acid. ... 

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