Method of initial rates vs integrated rate law

[Melody Haratian 2J]

Hi guys! Can someone explain some of the differences between method of initial rates and the integrated rate law? I know how to use both but am confused on which situations I should use each method in.

[allyssa bradley 1H]

Hi, this is a good question! One place to start, your method of initial rates (I'm thinking the dA/dt, correct me if I'm wrong) actually gives you those initial rates somewhere in the problem. Comparatively, the integrated rate law only helps you with k, t, and concentrations, so you would need to then go into your rate law equation to derive that rate. I'm trying to give a pretty simple answer, but quote me if I got anything wrong or you have any clarifying questions!

[Yichen Fan 3A]

I think it will depend on which experimental data you have. If you conduct multiple experiments using different initial concentration, you can use method of initial rate to find the order of the reactant and k. If you choose to measure multiple concentrations at different time during a single reaction, you will use the integrated rate law.