Question

The decomposition of NH3 on platinum surface is zero order reaction. If rate constant (k) is $4\times {10}^{-3}m{s}^{-1}$ , how long will it take to reduce the initial concentration of $N{H}_3$ from 0.1 M to 0.064 M.

Answer 1

Given that:
$k=4\times {10}^{-3}m{s}^{-1}$
$\left[A_0\right]$ = 0.1 M
$\left[A\right]$ = 0.064 M
For a zero-order reaction,
$k=\frac{1}{t}\left(\right[A_0]-[A\left]\right)$
$4\times {10}^{-3}m{s}^{-1}$ = $\frac{1}{t}\left(\right[0.1]-[0.064\left]\right)$
$t=\frac{0.1-0.064}{4\times {10}^{-3}}=0.009\times {10}^3=9seconds$