Changing the concentration of reactants affects the reaction rate by altering the frequency of collisions between reactant molecules. In general, increasing the concentration of reactants will increase the reaction rate, while decreasing the concentration will decrease the reaction rate. This is because a higher concentration of reactants leads to more frequent collisions, which in turn increases the likelihood of successful reactions.To determine the order of a reaction, you need to analyze the relationship between the reaction rate and the concentration of the reactants. The order of a reaction is the sum of the exponents of the concentration terms in the rate law equation. The rate law equation is given by:Rate = k[A]^m[B]^nwhere Rate is the reaction rate, k is the rate constant, [A] and [B] are the concentrations of the reactants, and m and n are the reaction orders with respect to reactants A and B, respectively.To determine the order of the reaction, you can perform a series of experiments in which you vary the concentrations of the reactants and measure the resulting reaction rates. By analyzing the data, you can determine the relationship between the reaction rate and the concentration of each reactant, which will allow you to determine the reaction orders m and n and the overall reaction order m + n .For example, if doubling the concentration of reactant A doubles the reaction rate while the concentration of reactant B remains constant, the reaction is first order with respect to reactant A m = 1 . If doubling the concentration of reactant B quadruples the reaction rate while the concentration of reactant A remains constant, the reaction is second order with respect to reactant B n = 2 . In this case, the overall reaction order would be m + n = 1 + 2 = 3.