Method of Initial Rates
Definition and meaning of Method of Initial Rates in chemistry.
Method of initial rates is an experimental kinetics technique used to determine the exact rate law and reaction orders of a given chemical reaction.
In more detail
In this analytical method, the reaction rate is meticulously measured at the very beginning of the reaction (the initial rate) across several distinct experimental trials. By systematically varying the starting concentration of one specific reactant while keeping all others completely constant, physical chemists can directly observe how the initial rate fluctuates. Mathematically comparing the rates across these different trials allows for the precise determination of the kinetic order of reaction with respect to each individual reactant in the system.
Key facts
| Field | Physical Chemistry |
|---|---|
| Primary Purpose | Determining experimental rate laws |
| Key Measurement | Reaction rate exactly at time zero |
By doubling the initial concentration of a reactant A and observing that the initial rate perfectly quadruples, a chemist can confidently conclude that the reaction is second order with respect to reactant A.
Frequently asked questions
Why use the initial rate instead of rates measured later in the reaction?
Initial rates are used because the exact concentrations of reactants are known, and any potential reverse reaction is entirely negligible at the very beginning.
What valuable information does this specific method provide?
It provides the specific reaction orders for each reactant, which are then combined to write the complete experimental rate law equation.