Answer to Question #126389 in Physical Chemistry for Abid Amin

Question

Q. Given the rate of the third order reaction:
A+B+C→P is 0.05 Ms-1
If the [A] = 0.05 M, [B] = 0.01M, and [C] = 0.25M. What is the third order rate constant?

Q. What are the units of the rate constant for a second-order reaction?

Q. Given the first order reaction is completed 90% in 30 minutes at 298 K. Calculate the rate

Answer 1

Given reaction

(1) A+B+C --------- P

Rate of reaction =0.05MS^-1

R = K.(A)¹.(B)¹.(C)¹

0.05 =K. (0.05) . (0.01) . (0.25)

K = 0.05/(0.05) .(0.01). (0.25)

K =10000/25 = 400 M^-2. S^-1

Rate of constant = 400 M².S^-1

(2) Unit of rate constant for a second order reaction M^-1.S^-1 OR L.mol^-1.s^-1

(3) For first order reaction

Rate constant K = 2.303/30 log100/10

K = 20303/30 LOG10 = 2.303/30 min^-1 = 0.076min^-1