Final answer:
To determine the rate law, compare changes in initial concentrations with rates of reaction to find orders of reactants and sum the orders to find the overall reaction order. The rate constant k is calculated by substituting the known concentrations and initial reaction rates into the rate law.
Step-by-step explanation:
Determining the Rate Law, Reaction Order, and Rate Constant
To determine the rate law of a chemical reaction, one must analyze experimental data that shows how the concentration of reactants affects the rate of the reaction. The rate law can be represented by the formula rate = k[A]m[B]n, where k is the rate constant, and m and n are the orders of the reaction with respect to reactants A and B, respectively. These orders can be determined by observing how changes in concentrations affect the rates of reaction.
Once the rate law is established, the overall reaction order is the sum of the exponents m and n. To find the value of k, we can use data from an experiment. Choosing initial concentrations and corresponding initial rates, we can substitute these values into the rate law and solve for k, ensuring that the units for k accommodate the units of concentration and rate, and result in the correct units for the rate of reaction.
The units of k will depend on the overall reaction order. For example, if the concentration units are mol³/L³, and the reaction is second order, then the units for k should be mol-2 L²/s to ensure that the rate is expressed in terms of mol/L/s.