Posted by brian on .
Cesium137 has a half life of 30.0 years. If initially there are 8.0 kg of cesium137 present in a sample, how many kg will remain after 60.0 years?

chem 
DrBob222,
k = 0.693/t_{1/2} and substitute k into the equation below.
ln(No/N) = kt
No = 8 kg
N = ?
k from above
t = 60.0 years.