Here’s a explanation of how to find the order of a reaction:
1. Using initial rates
- Change the concentration of a reactant and see how the reaction rate changes.
- If doubling the concentration doubles the rate, it’s first order.
- If doubling the concentration quadruples the rate, it’s second order.
- If changing the concentration doesn’t change the rate, it’s zero order.
- Do this for each reactant to find the overall order.
2. Using concentration vs. time
- Measure how concentration changes over time.
- Plot the data:
- Straight line of [A] vs time → zero order
- Straight line of ln[A] vs time → first order
- Straight line of 1/[A] vs time → second order
In short: You determine the order by experimentally seeing how concentration affects the rate or how concentration changes with time.