Posted by Leyah on Monday, July 19, 2010 at 1:02pm.
The halflife of radon222 is 3.82 days. If a sample of gas contains 4.38ug of radon222, how much will remain in the sample after 15.2 days?

Chemistry  DrBob222, Monday, July 19, 2010 at 1:13pm
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.