The half-life of ⁴²K is 12.5 h.How much will remain after 83 h if the original sample contained 256 g of ⁴²K?

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The half-life of a radioactive isotope is the time it takes for half of the atoms in a sample to decay. After one half-life, half of the original sample remains. After two half-lives, half of the remaining sample remains, or one-fourth of the original sample. After three half-lives, half of the remaining sample remains, or one-eighth of the original sample. And so on.In this case, the half-life of ⁴²K is 12.5 h. After 83 h, which is 6.64 half-lives, the amount of ⁴²K remaining will be 256 g / 2^6.64 = 2.6 g.

The Half-Life of 42K Is 12

The Half-Life of ⁴²K Is 12