How long will it take for a 18.0-g sample of iodine-131 to decay to leave a total of 2.25 g of the isotope? The half-life of iodine-131 is 8.07 days

Answer 1

k = 0.693/t_1/2

Then ln(No/N) = kt
No = 18/-
N = 2.25
k from above.
Solve for t.

Answer 2

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