Dimensions and Dimensional Analysis

Dimensions are the currency of science. Therefore, it is of utmost importance, especially in enzyme kinetics, to take care of dimensions and to perform the dimensional analysis of kinetic equations and expressions in order to avoid the algebraic mistakes and to check the derivation of rate equations. 

The dimensions are referring to the three major properties of the universe the matter, the time, and the energy. Earlier, a c.g.s. system of units (centimeter, gram, and second) was in general use, but now, another system ofunits has been adopted in many parts of the world, known as SI (System International d Unites) (Table 1). 

In this international system of units, the seven fundamental units are established length = meter (m), mass = kilogram (kg), time = second (s), electrical current = ampere (A), temperature = degree Kelvin (°K), luminosity = candelas (cd), and the quantity of matter = mole (mole). Many traditional units, such as calories (cal) or kilocalories (kcal) and centimeters (cm), are stUl in common use among chemists. 

In chemistry, the quantity of matter is usually expressed in moles (mole) and the concentration of matter is usually expressed in mole/liter (M). Reaction rates are expressed in mole/Uter/second (Ms 0- The first-order rate constants have the dimension oftime (s ) and the second-order rate constants have the dimension of concentration x time (M s ) zero-order rate constants have the dimension of concentration x time (M s ). 

Most kinetic expressions and kinetic equations are presented in the literature, as well as in this book, without dimensions the dimensions of kinetic parameters. 

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Astarita6 presents a brief history of the concept of dimensions and dimensional analysis from Euclid to the present day. 

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