Chemistry

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

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  1. k = 0.693/t1/2

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

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