Question

What is the rate constant for the reaction: A + B → C if the concentration of A is 0.1 M, B is 0.2 M, and the initial rate of formation of C is 2.5 x 10^-3 M/s? (Assume the reaction follows first-order kinetics with respect to both A and B.)

Answer 1

For a reaction that follows first-order kinetics with respect to both A and B, the rate law can be expressed as:rate = k[A]^1[B]^1where rate is the initial rate of formation of C, k is the rate constant, and [A] and [B] are the concentrations of A and B, respectively.Given the initial rate of formation of C  rate  = 2.5 x 10^-3 M/s, the concentration of A  [A]  = 0.1 M, and the concentration of B  [B]  = 0.2 M, we can solve for the rate constant  k  using the rate law equation:2.5 x 10^-3 M/s = k 0.1 M  0.2 M To solve for k, divide both sides of the equation by  0.1 M  0.2 M :k =  2.5 x 10^-3 M/s  /   0.1 M  0.2 M  k =  2.5 x 10^-3 M/s  /  0.02 M^2 k = 1.25 x 10^-1 M^-1s^-1The rate constant  k  for the reaction is 1.25 x 10^-1 M^-1s^-1.