A first order reaction is 15% complete in 20 minutes. How long will it take to complete 60%?

Explanation

`k=(2.303)/(t) log"" ([A]_(0))/([A])`
First Order Equation, `[A_(0)]=100`
[A]=100-15=85
`k=(2.303)/(20)log"" (100)/(85)`
`k=(2.303)/(20)xx0.0706=8.13xx10^(-3)" Min"^(-1)`
In second case
`[A]_(0)=100`
[A]=100-60=40
`t=(2.303)/(8.13xx10^(-3)) log""(100)/(40)`
`t=(2.303)/(8.13xx10^(-3))xx0.3979`
t=112.7 min.