rate constant

In chemistry, the rate constant (often denoted as k) is a proportionality constant that relates the rate of a chemical reaction to the concentrations of the reacting substances. It is a crucial component in understanding how fast a reaction proceeds.12

The rate constant is influenced by several factors, most notably temperature. The Arrhenius equation mathematically describes this relationship, showing that an increase in temperature significantly increases the rate constant. This equation also incorporates A, which represents the frequency of effective collisions between molecules, and E, the activation energy required for the reaction to occur.3

The units of the rate constant vary depending on the order of the reaction, which is determined by how the rate depends on the concentrations of reactants. For instance, in a second-order reaction where the rate is proportional to the concentrations of two reactants, the rate expression might be v = k[A][B].2