The half-life of iodine-131 is 8.1 days. How much of a 45.0 mg sample will remain after 24.3 days?

Name: The half-life of iodine-131 is 8.1 days. How much of a 45.0 mg sample will remain after 24.3 days?
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Question

Quizplus · Accepted Answer

After 24.3 days, which is exactly three half-lives of iodine-131 (since 24.3 days / 8.1 days/half-life = 3 half-lives), the amount of the substance remaining would be (1/2)^3 = 1/8 of the original amount. Therefore, 45.0 mg * 1/8 = 5.625 mg, which rounds to 5.62 mg.

The Half-Life of Iodine-131 Is 8