chemistry
posted by Shay .
Iodine131, a beta emitter, has a halflife of 8 days.How many grams of a 10.0g sample of iodine131 would remain after 56.0 days?

k = 0.693/t_{1/2}
ln(No/N) = kt
No = 10.0g
N = unknown
k from above
t = 56
Another way to solve this:
10/2^{n}
56 days is 7 half lives so
10/2^{7} = ?