Determination of a Rate Equation

The speed equation determines the speed equation with formal speed = k [A] x [B] y. This shows how the rate of chemical reaction depends on the concentrations of reactants (A and B) and the rate constant k. The speed equation usually indicates which species are involved in the rate determination step and how much species are involved. The rate equation is used to explain how the product concentration increases or how the reactant concentration decreases over time and this equation can also be used to calculate one or more reactants Shows how the concentration directly influences the speed.

The kinetic or kinetic equation of the chemical reaction is a differential equation that relates the reaction rate to the reactant concentration or pressure and constant parameters (usually rate coefficient and partial reaction order). In order to determine the velocity equation for a particular system, the reaction rate can be combined with the mass balance of the system. Furthermore, there are a series of differential equations for the study of thermodynamics and quantum mechanics.

In these formulas, k (T) is the reaction rate coefficient or reaction rate constant. However, it is not actually a constant because it contains all the parameters affecting the reaction rate, except for the concentrations explicitly considered. Among all parameters affecting the reaction rate, temperature is usually the most important parameter and is calculated by the Arrhenius equation. The indices n and m are called reaction orders and depend on the reaction mechanism. In a basic (single step) reaction, the order of each reactant is equal to its stoichiometric coefficient. However, for complex (multi-stage) reactions this is usually inaccurate and the rate equation is determined by a detailed mechanism, as shown by the reaction to H 2 and NO as follows.

These are called Michaelis - Menten equations. Here, Vmax represents the maximum initial reaction rate, and Km represents the Michaelis constant. Km shows an initial reaction rate of 1 / 2Vmax. This equation is basically a hyperbolic function that proves saturation phenomena. This formula is derived based on specific assumptions (see "Derived" column on page 55) and is not always applied to all enzymatic reactions. In practice, however, this formula is applicable to many enzymatic reactions and Km is used as an indicator of the affinity between the enzyme and the substrate (the smaller the Km, the greater the affinity).