# Calculation of rate law for multi step reaction [closed]

Please help me to solve this one. I'm having a bit of a hard time grasping these concepts.

## closed as off-topic by airhuff, a-cyclohexane-molecule, A.K., Jon Custer, MithoronOct 7 '18 at 20:31

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In the pre-equilibrium you treat the first reaction as an equilibrium to find $$[\ce{A}]$$ and substitute this into the second rate expression $$\mathrm d[\ce{P}]/\mathrm dt=k_2[\ce{A}][\ce{B}]$$. In the steady state approach you assume that the intermediate species $$[\ce{A}]$$ has a small rate of change thus let $$\mathrm d[\ce{A}]/\mathrm dt = 0$$ and find $$[\ce{A}]$$ this way.