B Chemical Equilibrium

White, W.B., Johnson, S.M., and Dantzig, G.B. Chemical equilibrium in complex mixtures. J. Chem. Phys. 28, 751-755 (1958), Warga, J. A convergent procedure for solving the thermo-classical equilibrium problem. J,. Soc. Ind. Appl. Math. 11, 594-606 (1963). 

Define and illustrate the following terms (a) reversible reaction, (b) chemical equilibrium, (c) equiUbrium constant. 

Library of Congress Cataloging in Publication Data Guenther, William B Chemical equilibrium. 

An example of enhanced ion production. The chemical equilibrium exists in a solution of an amine (RNH2). With little or no acid present, the equilibrium lies well to the left, and there are few preformed protonated amine molecules (ions, RNH3+) the FAB mass spectrum (a) is typical. With more or stronger acid, the equilibrium shifts to the right, producing more protonated amine molecules. Thus, addition of acid to a solution of an amine subjected to FAB usually causes a large increase in the number of protonated amine species recorded (spectrum b). 

S. Gordon and B. J. McBride, "Computer Program for Calculation of Complex Chemical Equilibrium Composition, Rocket Performance, Incident and Reflected Shocks, and Chapman-Jouget Detonations," NASA SP-273, Interim Revision, NTIS, Springfield, Va., Mar. 1976. 

Denbigh, K., The Principles of Chemical Equilibrium, Cambridge University Press (1971) Avery, H. E. and Shaw, D. J., Basic Physical Chemistry Calculations, Butterworths (1971) Gross, J. M. and Wiseall, B., Principles of Physical Chemistry, Macdonald and Evans (1972) Kubaschewski, O., Evans, E. LI. and Alcock, C. B., Metallurgical Thermochemistry, 4th edition, Pergamon Press (1967)... 

The thermodynamic effects of electric fields and are well known. Application of an electric field to a solution can affect the chemical equilibrium. For example, in Eq. (18) where C has a large dipole moment and B has a small dipole moment the equilibrium is shifted toward C under the action of an electric field. 

Fowle and Fein (1999) measured the sorption of Cd, Cu, and Pb by B. subtilis and B. licheniformis using the batch technique with single or mixed metals and one or both bacterial species. The sorption parameters estimated from the model were in excellent agreement with those measured experimentally, indicating that chemical equilibrium modeling of aqueous metal sorption by bacterial surfaces could accurately predict the distribution of metals in complex multicomponent systems. Fein and Delea (1999) also tested the applicability of a chemical equilibrium approach to describing aqueous and surface complexation reactions in a Cd-EDTA-Z . subtilis system. The experimental values were consistent with those derived from chemical modeling. 

Detonation pressure and temperature of hydrogen-air mixtures starting from 101.3 kPa (1 atm) and 298 K (25°C). Chapman-Jouguet calculations using the Gordon-McBride code. (After Gordon, S. and McBride, B.J., Computer Program for Calculation of Complex Chemical Equilibrium Compositions and Applications, NASA Reference Publication, Cleveland, Ohio, 1994.)... 

White, W. B., 1967, Numerical determination of chemical equilibrium and the partitioning of free energy. Journal of Chemical Physics 46,4171-4175. 

A strictly dehned region of chemical shifts of C2, C4, and C5 atoms in A-oxides of 4A-imidazoles allows to dehne clearly the position of the A-oxide oxygen atom (102). Chemical shifts of the a-C nitrone group in a-N-, O-, and S-substituted nitrones are located in the region of 137 to 150 ppm (388, 413). On the basis of 13C NMR analysis of 3-imidazoline-3-oxide derivatives, the position of tautomeric equilibria in amino-, hydroxy-, and mercapto- nitrones has been estimated. It is shown that tautomeric equilibria in OH- and SH-derivatives are shifted toward the oxo and thioxo forms (approximately 95%), while amino derivatives remain as amino nitrones (413). In the compounds with an intracyclic amino group, an aminonitrone (A) - A-hydroxyaminoimino (B) tautomeric equilibrium was observed (Scheme 2.76), depending on both, the nature of the solvent and the character of the substituent in position 2 of the heterocycle (414). 

Figure 1.1 (a) Chemical potential diagrams for systems forming a complete range of solid solutions. The tangent shows at its terminal points, X, Y the chemical potentials of the elements x and y which are in equilibrium with the solid solution of composition M (b) Potentials for the system A-B, which forms the two stable compounds the stoichiometric A2B and the non-stoichiometric AB2. The graph shows that there are many pairs of potentials A, B in equilibrium with A2B and only one pair for a particular composition of AB2 AB is metastable with respect to decomposition to A2B and AB2... 

Here we are considering the dynamic equilibrium between molecular species in the gas phase and the adsorbed gas species on a surface. Let us consider the following quasi-chemical equilibrium between the species B in the gas, Bg, and the available sites at the surface of the adsorbate ... 

The fundamental law of chemical equilibrium is the law of mass action, formulated in 1864 by Cato Maximilian Guldberg and Peter Waage. It has since been redefined several times. Consider the equilibrium between the four chemical species A, B, C and D ... 

A chemical equilibrium results when two exactly opposite reactions are occurring at the same place, at the same time and with the same rates of reaction. When a system reaches the equilibrium state the reactions do not stop. A and B are still reacting to form C and D C and D are still reacting to form A and B. But because the reactions proceed at the same rate the amounts of each chemical species are constant. This state is a dynamic equilibrium state to emphasize the fact that the reactions are still occurring—it is a dynamic, not a static state. A double arrow instead of a single arrow indicates an equilibrium state. For the reaction above it would be ... 

In such an apparatus, a chemical reaction takes place with a conversion of compound A into the products B and C. Typically, a sharp pulse of component A is fed into the column. During the passage through the column, compound A is converted into the products B and C and the amount of component A decreases. Because of their different retention times, the products B and C are concomitantly separated from each other and component A. Due to the removal of the products from the reaction zone, chemical equilibrium is never reached and the reaction will ideally proceed until the total conversion of the compound A. The reaction may take place in the stationary and/or the mobile phase. Heterogeneous reactions maybe either catalyzed by the packed adsorbent or by an additional catalyst, which is mixed with the adsorbent. 

B. Interpretation of Volume Changes Let us consider a general chemical equilibrium... 

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