Question

Manganese-56 decays by beta emission and has a half-life of 2.6 hours. How many half-lives are there in 24 hours? How many mg of a 20.0 mg sample will remain after five half-lives?

Answer 1

Step-by-step explanation:

Given that,

Manganese-56 decays by beta emission and has a half-life of 2.6 hours.

We need to find no of half lives in 24 hours. It can be calculated by dividing 24 hours by 2.6 hours. So,

`T=(24)/(2.6)=9.23\ \text{half lives}`

Let x mg of a2 0 mg sample remain after 5 half-lives.

`x=20\ mg* (1)/(2^5)\\\\x=0.625\ \text{mg}`

Hence, there are 9.23 half lives and 0.625 mg of sample will remain after 5 half lives.