For the hypothetical reaction A → B, calculate the average rate of disappearance of A if the initial concentration of A is 0.91 M and the concentration of A after 90 minutes is 0.11 M.

The right answer is 8.9 x 10^-3 M/min

Explanation:

           A → B

-d [A]/dt  = K [A]

ΔA/Δt     = - (C2 -C1)/t2 - t1

               = - (0.11 - 0.91)/90

               = 8.9 x 10^-3 M/min

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

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