The half-life of I-131 is 8.00 days. If a medical treatment involves a dose of 400. mg of I-131, how much of the isotope remains after 32.0 days?

Name: The half-life of I-131 is 8.00 days. If a medical treatment involves a dose of 400. mg of I-131, how much of the isotope remains after 32.0 days?
Brand: Quizplus
Rating: 4.8 (55 reviews)

Question

Quizplus · Accepted Answer

The half-life of I-131 is 8 days, so after 32 days (which is 4 half-lives), the amount of I-131 will be reduced to (1/2)^4 of the original amount. (1/2)^4 = 1/16, so 400 mg * 1/16 = 25 mg.

The Half-Life of I-131 Is 8