a sample of a radioisotope had a mass of 100.0 grams. After exactly 24 days, 6.25 grams remained. The half life of the isotope is _________

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  1. ln(No/N) = kt
    No = 100
    N = 6.25
    t = 24 days.
    Solve for k, then substitute into the equation below.
    k = 0.693/t1/2 and solve for t1/2

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