Question

Explain what is meant by the rate law of a reaction.

Short answer

The rate law of a reaction is a mathematical equation that relates the rate of a chemical reaction to the concentrations of its reactants. It is empirically determined and usually takes the form of 'Rate = k \([A]^m \times [B]^n\)'. The rate law models how a reaction will proceed over time, enabling control over reaction rates and gaining insights about the reaction mechanism and the effect of temperature.

Step-by-step solution

Define the rate law

The rate law of a reaction is a mathematical expression that illustrates the relationship between the rate at which a chemical reaction proceeds and the concentration of the reactants. As such, the rate law is a crucial component in determining the kinetics, or speed, of a chemical reaction.

Explain the construction of a rate law

Rate laws are determined experimentally and are usually of the form 'Rate = k \([A]^m \times [B]^n\)', where 'Rate' denotes the rate of the reaction, 'k' denotes the rate constant for the reaction, '[A]' and '[B]' denotes the concentrations of the reactants and 'm' and 'n' denote the orders of the reaction with respect to the reactants A and B respectively. The overall order of reaction is the sum of individual orders (m + n). The orders of reaction represent the effect of reactant concentrations on the rate of reaction and can be 0, 1, 2 or sometimes fractions.

Discuss the significance of the rate law

The rate law is significant because it allows scientists to model how a reaction will proceed over time. This has practical importance in a wide array of fields, from designing industrial processes to understanding biological systems. By controlling the concentrations of reactants, the rate of a reaction can be manipulated. Additionally, from the rate constant, the rate law also allows information about the reaction mechanism and the effect of temperature on reaction rate to be obtained.