Question

In a certain first order reaction, half the reactant was decomposes in 500 seconds. How long will it take for only one-tenth of the material to be left?​

Answer 1

Answer:

The pertinent equations are:

N - N(initial) exp (-kt) where

k = (ln 2)/ (half-life)

With a half-life of 1000 sec, k = 0.0006931

Thus, when N = 0.1000 and N (initial) =1.

t = 3322 seconds

This is a reasonable answer, as 0.1250 N (initial) would be left after 3 half-lives (3000 sec) and 0.6125 N (initial) would be left after 4 half-lives (4000 sec)