Question

The decomposition of A to B is a first-order reaction with a half-life of 85.9 min when the initial concentration of A is 0.483 M: A → 2B How long will it take for this initial concentration of A to decrease by 23.0%? PLEASE HURRY I DONT HAVE MUCH TIME TO ANSWER THIS

Answer 1

Half life = 85.9 min

Initial concentration of A = 0.483

Use integrated equation of first order.

Ln (At/A0) = - kt

Here At is the concentration at time t.

A0 is the initial concentration.

k is rate constant and t is the time.

Calculate the rate constant using following formula

k = 0.693 / half life = 0.693 / 85.9 min = 0.0080675 min^-1

find out 23 percent of A0

= 0.483 x 23/100

=0.1111

At = 0.483-0.111 = 0.372

Lets plug in all values to get the t

Ln ( 0.372/0.483) = - 0.0080675 x t

t = 32.4 min

so the time required = 32.4 min