When Is a Reaction First Order?

A first-order reaction is a reaction that proceeds at a rate that depends linearly on only one reactant concentration.

How do you determine reaction order?

In order to determine the reaction order, the power-law form of the rate equation is generally used. The expression of this form of the rate law is given by r = k[A]^x[B]^y.

What does it mean to be a first order reaction?

: a chemical reaction in which the rate of reaction is directly proportional to the concentration of the reacting substance — compare order of a reaction.