In the reaction A+B to give C+D, how do you obtain the kinetic law?

3 Answers

  • Dr W
    Lv 7
    4 weeks ago

    it will be of the from

    .. rate = k * [A]^m * [B]^n

    where m and n are determined experimentally.

  • 4 weeks ago

    Thanks for the efforts, but that's not what I mean, I meant the kinetic law, r= k *** (complicated expression where there are concentrations of A,B,C,D), I know it starts with rA=kCA, etc, but I cannot reach the final result.

  • 4 weeks ago

    You have to determine it experimentally. In each experiment, you vary the concentrations of A and B while measuring the rate of the reaction.

    A good way to start is with equal concentrations. Then hold A constant at that equal concentration value and double B. Then, hold B constant at that equal concentration value and double A.

    What you now need to do is look at how the concentration changes affect the rate. For example, if A is doubled (B is constant) and the fate doubles, then the reaction is first order in A. If the rate does not change, the reaction is zero order in A (meaning that A does not appear in the rate law).

    This technique is called the method of initial rates. I have some solved examples here:

Still have questions? Get your answers by asking now.