The cadmium isotope 109Cd has a half-life of 462 days. A sample begins with 1.0×10^12^109 Cd atoms.?
(A) How many 109Cd atoms are left in the sample after 86 days?
(B) How many 109Cd atoms are left in the sample after 900 days?
(C) How many 109Cd atoms are left in the sample after 5300 days?
Update:Sorry the I messed up in the writing of the problem its not 1.0×10^12^109 its 1.0×10^12 ^109Cd
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Verified answer
(A)
(1.0 × 10^12 atoms) × (1/2)^(86 days / 462 days) = 8.79 × 10^11 atoms
(B)
(1.0 × 10^12 atoms) × (1/2)^(900 days / 462 days) = 2.59 × 10^11 atoms
(C)
(1.0 × 10^12 atoms) × (1/2)^(5300 days / 462 days) = 3.52 × 10^8 atoms
This problem is worked exactly like the Barium atom problem here:
https://answers.yahoo.com/question/index?qid=20210...
Just put this half-life and the initial number of atoms into the integrated rate law and solve for the number of atoms remaining.
1.0×10^12^109 ?? what does this mean ? there are not that many atoms in the universe.