Question

The reaction 2NO₂ → 2NO + O₂ obeys the rate law:

Δ[O₂]/ Δt = (1.40 x 10⁻² sec )[NO₂]² at 500. K.

If the initial concentration of NO₂ is 1.00 M, how long will it take for the [NO₂] to decrease to 0.358M?
A) 45.9 s
B) 73 s
C) 128 s
D) 1.40 x 10⁻² s
E) 39s

Answer 1

To find the time it takes for the concentration of NO₂ to decrease to 0.358M in the reaction 2NO₂ → 2NO + O₂, we can use the integrated rate law for a second-order reaction. The time is calculated to be 45.9 seconds.

Step-by-step explanation:

A second-order reaction is described by the rate law Δ[O₂]/Δt = (1.40 x 10⁻² sec)[NO₂]². We are given an initial concentration of NO₂ (1.00 M) and we need to determine how long it will take for the concentration of NO₂ to decrease to 0.358 M. To solve this problem, we can use the integrated rate law for a second-order reaction. By substituting the given values into the integrated rate law equation and rearranging, we can solve for time (t).

The correct answer is A) 45.9s.