Problema Solution
The radioactive element americium has a half-life of 432 years. Suppose we start with a 20-g mass of americium
How much will be left after 321 years?
Answer provided by our tutors
We assume X is left
M is the mass at the beginning, t is time
So we have
X = M*(1/2)^(t/432) = 20g *(1/2)^(t/432)
When t = 321 yrs
X = 20g *(1/2)^(321/432) = 11.95 g
So 11.95 g is left