However, we can use this guide or this formula to approximate our rates of multistep reactions as long as the concentrations of intermediates are held relatively low. Now that means suppose we have the following reaction a plus B react to form intermediate AB and then that intermediate AB reacts with C, some other guy to form ABC. Now this guy is out intermediate. Now, as long as the concentration of this guy is kept relatively low, we can approximate using these formulas here. So likewise, the rate of change or disappearance of A and B can be given by negative change in concentration of B divided by T. Now that only works if that intermediate concentration is kept low. Now let's talk about the rate law.