If 9.00 g of _27^60 Co (half-life = 5.30 y) are allowed to decay, how many grams would be left after 1.00 y and after 10.0 y?


g after 1.00 y
g after 10.0 y

k = 0.693/t1/2

Then ln(No/N) = kt
No is 9.00
N = ?
k from above
t = 1 y or 10 y (two separate problems.)