Order of reaction
It refers to the relation between the rate and concentration of the elements taking part in a chemical reaction and can be obtained by calculating the rate equation of that reaction. The rate equation can determine the entire composition of the mixture consisting of all the elements. In other words, it refers to the dependence of the concentration of all reactants in a chemical reaction on the rate law expression.
For example, the reaction rate is wholly dependent on the concentration of one species in a first-order chemical reaction. It is an experimental value, which means it is an experimentally determined parameter.
The value of the reaction order can be a fraction, an integer, or zero. Therefore, we can draw a graph of reaction rates for different reaction orders. For example, below is a graph between the concentration and time of different reactions, with a downward slope.
