Question

WHOEVER ANSWERS FIRST WILL GET BRAINLIEST!!!!

If the half-life of iodine-131 is 8 days, how old is a sample if only ¼ of the original amount remains? Write 2 - 3 sentences explaining your reasoning.

Answer 1

The half-life of a substance is the time the substance takes to decay until the amount of the sample is half of its initial amount.

In this problem, the half-life of iodine-131 is 8 days. This means that after 8 days, only half of the initial sample will be left. After another 8 days (16 days), the sample will be reduced by another factor 1/2, so only 1/4 of the initial sample will be left.

Since the initial sample was 0.96 g, after 16 days the amount of iodine left is m = 1(0.96g) = 0.24g