how do you find the rate order of the reaction 2 A + B -> C + D ?

Question

i know its
K[A]^1 and
K[B]^2 and

the rate law is K[A][B]^2

but i need to know why that it, please be detalistic and specific as possible

Answer 1

You measure the reaction rate based on changing the concentration of A without changing that of B and then use the exponents to rate them. It's a relatively simple experiment.

So:

KAB^2 means that the reaction will happen twice as fast if A is doubled. It means that the reaction will go four times as fast if B is doubled.

It's based on this:

(rate1)^n = A1
---------------------
(rate 2) = A2

n=1 means it's [A]^1 or [A]
n=2 means it's [B]^2

Answer 2

The overall order of a reaction is an experimental fact. This one is third order. The order bears no relationship to the balanced equation. All that the rate equation tells you is that 1 molecule of A and 2 of B are involved in the slowest step of the reaction.

Answer 3

This is not the basic reaction then, it must be made up of more fundamental reactions.