Question

The half-life of radon-222 is 3.82 days. If a sample of gas contains 4.38ug of radon-222, how much will remain in the sample after 15.2 days?

Answer 1

k = 0.693/t_1/2
Substitute k into the following:
ln(No/N) = kt
No = 4.38 ug.
N = solve for this.
k from above.
t = 15.2 days.