Question

"The elementary reaction 2 NO2(g) → 2 NO(g) + O2(g) is second order in NO2 and the rate constant at 600 K is 6.77 × 10-1 M-1s-1. The reaction half-life at this temperature when [NO2]0 = 0.45 M is ________ s."

Answer 1

Answer : The half-life at this temperature is, 3.28 s

Explanation :

To calculate the half-life for second order the expression will be:

$t_{1/2}=\frac{1}{k\times [A_o]}$

When,

$t_{1/2}$ = half-life = ?

$[A_o]$ = initial concentration = 0.45 M

k = rate constant = $6.77\times 10^{-1}M^{-1}s^{-1}$

Now put all the given values in the above formula, we get:

$t_{1/2}=\frac{1}{6.77\times 10^{-1}M^{-1}s^{-1}\times 0.45M}$

$t_{1/2}=3.28s$

Therefore, the half-life at this temperature is, 3.28 s