Answer:
[A] = 8.69x10⁻⁵g
Step-by-step explanation:
Kinetics law of a radioactive atom, A, is:
Ln[A] = -kt + ln[A]₀
Where [A] could be taken as mass of A after time t (In seconds),
k is rate constant = ln2 / Half-Life
[A]₀ is intial mass of A
k = ln2 / 14.9s = 0.04652s⁻¹
Time in seconds:
5min * (60s / 1min) = 300s
Replacing each value:
ln[A] = -0.04652s⁻¹*300s + ln[100.0g]
ln[A] = -9.35
[A] = 8.69x10⁻⁵g