Introducing the equilibrium constant

The equilibrium equation for the first step is shown in Scheme 5-2. Introducing the equilibrium constant Kw of water (Kw = [H+][0H ]/[H20] leads to the equation shown in Scheme 5-3. ATW can be combined with the constant K (defined by Kx = K[KW) to give the equation of Scheme 5-4. In the same way, the second step can be expressed as in Scheme 5-5. 

The equilibrium constant in Eq. 2 is defined in terms of activities, and the activities are interpreted in terms of the partial pressures or concentrations. Gases always appear in K as the numerical values of their partial pressures and solutes always appear as the numerical values of their molarities. Often, however, we want to discuss gas-phase equilibria in terms of molar concentrations (the amount of gas molecules in moles divided by the volume of the container, [I] = j/V), not partial pressures. To do so, we introduce the equilibrium constant Kt., which for reaction E is defined as... 

If we introduce the equilibrium constant for the overall reaction in the gas phase. 

Since in most practical circumstances at temperatures where vapour transport is used and at around one atmosphere pressure, the atomic species play a minor role in the distribution of atoms, it is simpler to cast the distribution equations in terms of the elemental molecular species, H2, 02 and S2, the base molecules, and the derived molecules H20, H2S, S02 and SO3, and eliminate any consideration of the atomic species. In this case, let X, be the initial mole fraction of each atomic species in the original total of N° atoms, and the variables Xi represent the equilibrium number of each molecular species in the final number of molecules, N/. Introducing the equilibrium constants for the formation of each molecule from the elemental atomic species, with a total pressure of one atmos, we can write... 

Inorganic and physical chemistry Chemical equilibrium 1 Introducing the equilibrium constant, K... 

Many reactions, however, do not run to completion. They will reach a point where they stop, but in this chapter you will learn that when they are in this state they are not really stopped at all. These reactions, where the products can readily reform the reactants, are known as reversible reactions. The way these reactions proceed is analogous to the systems in equilibrium that were discussed in Chapters 8 and 10 (vapor equilibrium and solutions). In the next three chapters, you will study the equilibrium of chemical reactions and learn more about the factors associated with it. The focus of this chapter is to introduce the equilibrium constant, which provides data about the relationships between reactants and products in a system at equilibrium, and Le Chatelier s Principle, which allows you to predict the effects of different stressors on reaction equilibria. 

If the effective diffusivities Di,e and Z)2,e do not differ markedly, then eq 97 can be expressed in a simplified form by introducing the equilibrium constant Kcq =... 

This chapter, after introducing the equilibrium constant, discusses briefly the rate of entropy production in chemical reactions and coupling aspects of multiple reactions. Enzyme kinetics is also summarized. 

Substituting for HCO3 in expression (8.7) and introducing the equilibrium constant values and partial pressure of CO2 in the resultant equation, we find... 

In this section, we discuss the thermodynamics of systems imdergoing chemical reactions. First we derive the conditions for equilibrium. Then, we generalize the Gibbs phase rule for reacting systems. Afterwards, we examine the calculation of the and introduce the equilibrium constant. Finally, we examine the influence of pressure and temperature on chemical reaction equilibria. 

The rate constants of first order for the forward and the backward reaction of step i are denoted by ki and k i = kijKi, respectively. Then, using Eqs. (III.3) and (III.4) and furthermore introducing the equilibrium constant A of the overall reaction A< B,... 

Since the determinations of stoichiometric coefficients v,y and extents of reaction have already been discussed and illustrated in 7.4, we need only introduce the equilibrium constant to complete the description of the stoichiometric approach to reaction equilibrium problems. The full implementation of the stoichiometric approach is described in 10.4.3, after we have reviewed common choices for standard states. 

Little is known about the NADH aitd NAD content of the cytosol. In order to estimate the NADH/NAD ratio, the cytosolic contents of malate, aspartate, glutamate and 2-oxoglutarate were determined by nonaqueous fractionation of spinach leaves (Table l). From these values the NADH/NAD ratio was calculated on the reasonable assumption that the reactions catalyzed by the cytosolic malate dehydrogenase and glutamate oxaloacetate transaminase are near to equilibrium. Introducing the equilibrium constants of these enzymes 2.8. 10 at pH 7.0 (4), Kqqt... 

A chemical reaction is an irreversible process that produces entropy. The changes in thermodynamic potentials for chemical reactions yield the affinity A. All four potentials U, H, A, and G decrease as a chemical reaction proceeds. The rate of reaction, which is the change of the extent of the reaction with time, has the same sign as the affinity. The reaction system is in equilibrium state when the affinity is zero. This chapter, after introducing the equilibrium constant, discusses briefly the rate of entropy production in chemical reactions and coupling aspects of multiple reactions. Enzyme kinetics is also summarized. 

ECiev schemes introduce the equilibrium constant K into expressions for the electrode concentrations, parameter extraction is feasible at the equal (chemical) D limit (see below). 

We have introduced the equilibrium constant in terms of a ratio of rate constants, but the original research on chemical equilibrium was developed many years before the principles of kinetics. In 1864, two Norwegian chemists, Cato Guldberg and Peter Waage, observed that at a given temperature, a chemical system reaches a state in which a particular ratio of product to reactant concentrations has a constant value. This is a statement of the law of chemical equilibrium, or the law of mass action. 

In this section, we introduce the equilibrium constant, its different forms and its properties. 

By denoting = BT ln Kj, we introduce the equilibrium constant K,. For the equilibrium concentrations of reagents we obtain (2.15) which coincides with (2.4) for the equilibrium constant, K, introduced above from the kinetic consideration... 

Once more, 5 refers to liquids or solids in pure form, i, to constituents in the solution. We separate out terms that do not depend on the solution composition from those that do, thereby introducing the equilibrium constant... 

In this section, I explain how reactions reach equilibrium. 1 also introduce the equilibrium constant, which helps you find out how much product and reactant you have when the reaction is at equilibrium. 

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