The half-life of ²¹⁸Po is 3.1 minutes. How much of a 170 gram sample remains after 0.64 hours?

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The half-life of a radioactive substance is the time it takes for half of the substance 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 remains. After three half-lives, half of the remaining sample remains, or one-eighth of the original sample remains. And so on.In this case, the half-life of ²¹⁸Po is 3.1 minutes. After 0.64 hours, or 38.4 minutes, the sample has undergone 38.4 minutes / 3.1 minutes = 12.4 half-lives. Therefore, the amount of the original sample that remains is 170 grams / 2^12.4 = 0.032 grams.

The Half-Life of 218Po Is 3

The Half-Life of ²¹⁸Po Is 3