Use the rate law: rate = k[A]^m[B]^n
Determine reaction order from the exponents in the rate law
Find the order with respect to each reactant by varying one concentration at a time
Compare initial rates from experiments
If doubling a reactant doubles the rate, the order is 1
If doubling a reactant quadruples the rate, the order is 2
If doubling a reactant does not change the rate, the order is 0
If doubling a reactant halves the rate, the order is -1
Add the individual orders to get the overall reaction order
Use the integrated rate law and concentration-time data if needed
Check which plot is linear to identify order
A linear [A] vs time plot indicates zero order
A linear ln[A] vs time plot indicates first order
A linear 1/[A] vs time plot indicates second order
Use the half-life dependence on concentration if needed
Constant half-life indicates first order
Half-life proportional to initial concentration indicates zero order
Half-life inversely proportional to initial concentration indicates second order