Question

How can the rate law be determined?

Answer 1

Hint : We know that the rate law could be a mathematical relationship obtained by comparing reaction rates with reactant concentrations. The reaction order is that the sum of the concentration term exponents during a rate law equation.

Complete Step By Step Answer:
A rate law shows how a change in concentration affects the rate. The equation for a component A is $rate=k|A{{|}^{m}}$, where $m$ is the order of the reaction.
Zero Order: The rate does not depend on the concentration. Whatever we do to the concentration, the rate will not change. $rate=k|A{{|}^{0}}=k$
First Order: The rate is directly proportional to the concentration. If we double the concentration, we double the rate. If we triple the concentration, we triple the rate. If we halve the concentration, we halve the rate, and so on. $rate=k|A{{|}^{1}}=k|A|$
Second-Order: The rate is proportional to the square of the concentration. If we double the concentration, we multiply the rate by four. If we triple the concentration, we multiply the rate by nine. If we halve the concentration, we divide the rate by four, and so on. $rate=k|A{{|}^{2}}$
Since concentration changes during an experiment, we must measure the initial rate of the reaction, before the concentration has had a chance to decrease. We set up an experiment and measure the rate. Then we do another experiment in which we change only the concentration of component A. Let's say we double the concentration of A.
If the rate did not change, the reaction was zero order in A. If the rate doubles, the reaction is first order in A. If the rate quadruples, the reaction is second order in A.

Note :
Remember that the rate of a reaction is, perhaps, its most vital property because it dictates whether a reaction can occur during a lifetime. Knowing the speed law, an expression relating the speed to the concentrations of reactants can help a chemist adjust the reaction conditions to urge a more suitable rate.