Kinetics, definition

We adopt this kinetic definition of reaction order without reference to the actual number of molecules involved in each act of chemical transformation. In homogeneous reactions the kinetically determined order is equal to the number of molecules participating in the actual change of which the rate is being measured. In heterogeneous reactions this equality is not necessarily preserved. It will be convenient to call the order inferred from the effect of pressure on the time of half-change the apparent order, and to refer to the number of molecules involved as the true order of the reaction. We have now to consider the relation of the true and the apparent order in various cases. ... 

For convenience, Table A.2 in the Appendix provides a summary of the kinetic definitions and relations. 

Application of the kinetic definition of equilibrium to the mechanisms of Eqs. 40 42 yields the following relationship ... 

By rearrangement of equation (4), we can relate the bioconcentration factor to the rate constants for uptake and clearance of the toxicant. This may be compared with the earlier definition ofBCF based on equilibria the advantage of the kinetic definition is that the BCF may be deduced in cases where equilibration has not been achieved, provided that the rate constants can be estimated... 

This well-known result provides the kinetics definition of chemical equilibrium and relates the rate constant from thermodynamics to the ratio of the forward and reverse rate constants. 

The equilibrium state is a special kinetic state, namely that state in which the net change of all components with respect to time is equal to zero. For the sake of simplicity, in the ensuing discussion we shall assume all activity coefficients equal to unity. This assumption will in no way invalidate the conclusions reached. In addition, the principle of detailed balance must be obeyed. It states that at equilibrium the rate of conversion from a state A to another state B must exactly equal the direct conversion rate from state B to A. Although this sounds very much like the kinetic definition of equilibrium given above, the two are not exactly the same [9]. Consider the reaction scheme (1-38). 

In the next subsection, kinetic definitions and concepts are introduced. Subsequently, relevant properties of chemical operations w.r.t their modelling are outlined. Special... 

There are two distinct types of sequences leading from reactants to products through active centers. Sequences are either open or closed. An open sequence is one in which an active center is not reproduced in any other step of the sequence. A closed sequence, on the contrary, is one in which an active center is reproduced so that a cyclic reaction pattern repeats itself and a large number of molecules of products can be made from only one active center. A closed sequence is the best kinetic definition of catalysis. 

The Zener theory of the incomplete transformation phenomenon sometimes attending the bainite reaction in steel, as described by the overall reactions kinetics definition, has been shown by [2001Aar] to be able to describe neither the upper temperature limit for bainite formation in C-Fe-Mo alloys nor the average carbon concentration in retained austenite at the beginning of incomplete transformation. 

This is a thermodynamic definition of equilibrium equivalent to Equation (3.6). The kinetic definition of equilibrium follows from considering the overlap of occupied and vacant states in the solid and in the redox electrolyte. Fig. 3.13 shows a magnified plot of the energy distribution functions neariTp. In the case of a metal electrode, the states involved in electron transfer at equilibrium are in the exponential tails of the distribution functions W E) for the oxidised and reduced species, and as a consequence electron transfer involves states which are close (within a few k T) of E p. In the case of a semiconductor or insulator electrode, on the other hand, the density of electron levels in the solid is zero at... 

Ammonia decomposition over Fe, Cu, Ag, Au, and Pt Hydrolysis of starch to glucose catalyzed by acids Mixture of coal gas and air makes a platinum wire white hot Measurements on the rate of H2O2 decomposition Selective oxidation of ethanol to acetic acid over platinum Comprehensive paper on the H2 + O2 reaction on platinum foils, including reaction rates, deactivation, reactivation, and poisoning Definition of catalysis, catalyst, and catalytic force First quantitative analysis of reaction rates Systematic studies on the concentration dependence of reaction rates First concise monograph on chemical kinetics Definition of order of reaction Arrhenius equation k = u exp (-Ea/RT)... 

Unit definition One restriction unit is usually defined as the amount of enzyme required to digest completely 1 fig of DNA (typically phage A) in 1 hr. Because the definition relies on the activity at an end point of the reaction, it is distinguished from the usual kinetic definition of enzyme units based on the initial reaction rate. 

Equivalent to the sugar concentration according to mutarotadon kinetics definition. 

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