Question

The half-life period of a first order reaction is 15 minutes. The amount of substance left after one hour will be :

Answer 1

Heya!

Check out the attachment:))

Here, I've used the half life formula. The substance after every 15 minutes reduces to half of its initial amount. In 60 minutes (one hour), it undergoes 4 cycles and finally the amount of substance left over is 1/16th of initial amount.

Answer 2

The amount of substance left after one hour will be 1/16th of the original amount of the substance.

Explanation:

The half life equation,

$N=N_0(\frac{1}{2})^\frac{t}{t_{1/2} }$

Here, N is the mass of radioactive substance at time interval (t), $N_0$ is mass of the original amount of radioactive substance and $t_{1/2}$ is the half life.

Given $t_{1/2} =15 min$ and t = 1 hour = 60 min.

Substitute the values, in above equation, we get

 $N=N_0(\frac{1}{2})^\frac{60}{15} }$

$N=N_0(\frac{1}{2})^4$

$N =N_0\frac{1}{16}$

Thus, the amount of substance left after one hour will be 1/16th of the original amount of the substance.

#Learn More: Radioactive, half life.

https://brainly.in/question/11187953