Initial Rate Method
A technique for determining reaction orders by measuring the starting rate in a series of experiments with different initial concentrations.
Formula / equation
rate₂/rate₁ = ([A]₂/[A]₁)^m
Unit
mol/(L·s)
In depth
Using initial rates avoids complications from product accumulation and reverse reaction. Changing one reactant's concentration at a time and observing the rate response gives that species' order directly, and repeating for each reactant builds up the complete rate law.
Examples in the real world
Doubling [A] and observing a fourfold rate increase establishes second order in A.