Mass action law

About: Mass action law is a research topic. Over the lifetime, 168 publications have been published within this topic receiving 2684 citations.

A thermodynamic model of calculating mass action concentrations for structural units or ion couples in NaClO4-H2O and NaF-H2O binary solutions and NaClO4-NaF-H2O ternary solution

Abstract: A thermodynamic model of calculating mass action concentrations for structural units or ion couples in NaClO4-H2O and NaF-H2O binary solutions and NaClO4-NaF-H2O ternary strong electrolyte aqueous solutions was developed based on the ion and molecule coexistence theory (IMCT). A transformation coefficient was needed to compare the calculated mass action concentration and the reported activity, because they were usually obtained at different standard states and concentration units. The results show that transformation coefficients between the calculated mass action concentrations and the reported activities of the same components change in a very narrow range. The transformed mass action concentrations of structural units or ion couples in NaClO4-H2O and NaF-H2O binary solutions agree well with the reported activities. The transformed mass action concentrations of structural units or ion couples in NaClO4-NaF-H2O ternary solution are also in good agreement with the reported activities in a total ionic strength range from 0.1 to 0.9 mol/kg H2O by the 0.1 mol/kg step with different ionic strength fractions of 0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1, respectively. The results indicate that the developed thermodynamic model can reveal the structural characteristics of binary and ternary strong electrolyte aqueous solutions, and the calculated mass action concentrations of structural units or ion couples also strictly follow the mass action law.

The Free Energy of Electron Gas

Abstract: The energy and free energy of a semi‐degenerate gas obeying the Fermi statistics are computed as functions of temperature and concentration. The significance of the deviation of the free energy from the limiting high temperature value is illustrated by calculating the degree of thermal ionization of potassium vapor under conditions of high electron concentration.

The Rate of Transformation in Aqueous Solution of Methylammonium Cyanate into Methylurea

Abstract: When two molecules A and B react irreversibly with formation of a third substance C, the velocity v of the reaction, according to the classical law of mass action, ought to be directly proportional to the product of the concentrations Ca and Cb of A and B at the time of observation, that is v = k CaCb, where k is a constant. Although this equation has been successfully applied to some reactions there are many expectations, particularly reactions involving ions, where the irregularity is indicated by a progressive change in k with the initial concentration. Corrections have therefore had to be made in the above equation to account for the deviations from the classical mass action law. It has been suggested that the concentration terms should be replaced by thermo-dynamic activities, for the equilibrium constant K of the reaction A + B ↔ C is given exactly by K = a c/ a a a b, where a a, a b, and a c represent the activities of A, B, and C. Mere substitution of activities for concentrations in the velocity equation does not, however, explain the kinetic phenomena observed. The views that up to the present have met with most success have been put forward by Bronsted. He supposes that probably all reactions involve the primary formation from the reactants of a fugitive complex which is in thermo-dynamic equilibrium with them. The rate of the reaction is determined by the rate of formation of this complex X which then breaks down spontaneously into the final product, at a rate proportional to the concentration of X. Bronsted finally deduces the following equation for the velocity of reaction: v = ka a a b/ f x = k CaCb f a f b/ f x = k CaCbF, where the f terms represent activity coefficients. The reaction kinetic factor F is in a great measure dependent on the ionic concentration of the solution, and in general, it changes with the course of the reaction. The change on X, in a reaction involving ions, is the algebraic sum of the charges on A and B, and its activity coefficient depends in the same way as that of a substance on the medium. Bronsted's hypothesis has been tested in a great many reactions involving are expected to undergo a considerable change, owing to medium changes, either due to continued reaction, or to the addition of various electrolytes.