Suppose a laboratory has a 31 g sample of polonium-210. The half-life of polonium-210 is about 138 days. How many half lives of polonium occur in 966 days? How much polonium is in the sample 966 days later?

1 Answer
May 19, 2017

7 half-lives

0.24g 210Po

Explanation:

The number of half-lives is simply the number of days given (966d) divided by the half-life (138d), which is 7 half-lives.

The amount of 210Po remaining after t days is represented by the equation

N(t)=N0(12)tt12

where N(t) is the amount of substance remaining after t days,
N0 is the initial amount of substance,
t is the time in days, and
t12 is the half-life of the substance.

Plugging in known variables, we have

N(t)=(31g)(12)966138=0.24g 210Po