Suppose you have measured the kinetics of the reaction, 2 A + B → C.

Question

You measure the change in the B-concentration with time and determine the rate law is second order in A and zeroth order in B and has a rate constant of k = 0.0634 M^-1 s^-1.  

If the A-concentration is 0.28 M and the B-concentration is 0.26 M, what is the rate (in M s^-1)?  

{Enter your value with two significant figures. You may want to use E-notation to enter your value.)

Answer 1

Rate = k[A]^m[B]ⁿ

Since we are told the reaction is 2nd order in A and 0 order in B, and the rate constant is 0.0634 M^-1s^-1, we can write the rate law as...

Rate = k[A]²[B]⁰ = k[A]² = 0.0634 M^-1s^-1[A]²

Rate = 0.0634 M^-1s^-1[0.28 M]²

Rate = 0.00497 M^-1s^-1 = 4.97x10^-3 M^-1s^-1