The oxidation of NO(g) by O₂(g) is further examined at two temperatures under identical initial concentrations: [NO] = 0.020 M and [O₂] = 0.050 M.
T (K) Initial rate r (M·s⁻¹)
298 8.0 × 10⁻⁴
308 2.3 × 10⁻³
A proposed mechanism (identical to that in Question 3) leads to the rate law r = k[NO]²[O₂].
(a) Calculate the numerical value and units of the rate constant k at each temperature.
(b) Using the two values of k, determine the activation energy E_a for the rate-determining step. Show all work and include units.
(c) Discuss whether the temperature dependence of k obtained in part (b) is consistent with typical activation energies for elementary bimolecular reactions. In your discussion, address how the temperature dependence of the pre-equilibrium constant for the fast step could influence the accuracy of the E_a you calculated.