Question

Be sure to answer all parts. Chlorine oxide (ClO), which plays an important role in the depletion of ozone, decays rapidly according to the equation 2ClO(g) → Cl2(g) + O2(g) From the following data, determine the reaction order and calculate the rate constant of the reaction. Time (s) [ClO] (M) 3.59 × 10−3 8.44 × 10−6 4.21 × 10−3 7.22 × 10−6 4.83 × 10−3 6.31 × 10−6 5.45 × 10−3 5.60 × 10−6 6.07 × 10−3 5.04 × 10−6

Answer 1

rate of reaction(r1) = -D[ClO]/dt

                 = -8.44*10^-6/(3.59*10^-3)

                 = -2.35*10^-3 M/sec

rate of reaction(r2) = -D[ClO]/dt

                 = -7.22*10^-6/(4.21*10^-3)

                 = -1.71*10^-3 M/sec

order w.r.t ClO,

r1/r2 = (a1/a2)^n

(-2.35*10^-3)/( -1.71*10^-3) = ((8.44*10^-6)/(7.22*10^-6))^n

n = 2

so that,

rate law , rate = k[ClO]^2

             (2.35*10^-3) = K(8.44*10^-6)^2

RATE CONSTANT (k) = 3.3*10^7 M-1.s-1