# Rate of reaction

consider

3A + 5B ----> 4C + 2D

if this is an elementary process

the rate of reaction is given as

r = k [A]3 [ B ]5 , where k is rate constant, [x] are concentrations

so my question is , why is the rate of production of A = 3 times the rate of reaction?

since the rate of reaction has already taken into account the 3 moles of A, shouldn't the rate of production of A = rate of reaction ?

thanks!