Chemistry question, need help!! Thank you!?

What is the half‑life of an isotope that decays to  

6.25% of its original activity in 72.9 h?

 

1 Answer

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  • Bryce
    Lv 7
    8 months ago

    0.0625= e^(72.9k)

    ln0.0625= 72.9k; k= ln0.0625/ 72.9

    0.5= e^(t*ln0.0625/ 72.9)

    ln0.5= t*ln0.0625/ 72.9; t= 18.225 hours

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