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The cadmium isotope 109Cd has a half-life of 462 days. A sample begins with 1.0 * 1012 109Cd atoms. How many are left after (a) 50 days, (b) 500 days, and (c) 5000 days?

 Mar 21, 2022
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1 -  R ==10^12  x  1/2^(50/462)

      R==10^12   x   0.92772870876

      R  ==927,728,708,762 - atoms remain after 50 days.

 

2 - R ==10^12  x  1/2^(500/462)

      R ==10^12  x    0.47229131720

      R ==472,291,317,203 - atoms remain after 500 days.

 

3 - R ==10^12  x  1/2^(5000/462)

      R ==10^12  x    5.5220408368 x 10^-4

      R ==552,204,084 - atoms remain after 5000 days.

 Mar 21, 2022

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