Barium-122 has a half-life of 2 minutes. If 10.0 g of Ba-122 is produced in a nuclear reactor, identify the quantity of Ba-122 that will remain 10 minutes after production ceases.

Question

Quizplus · Accepted Answer

The half-life of Ba-122 is 2 minutes, meaning the quantity of Ba-122 will halve every 2 minutes. In 10 minutes, this halving will occur 5 times (10 minutes / 2 minutes per half-life = 5 half-lives). Starting with 10.0 g, after 5 half-lives, the quantity remaining is $10.0 g \times (\frac{1}{2})^5 = 10.0 g \times \frac{1}{32} = 0.3125 g$, which rounds to 0.313 g.

Barium-122 Has a Half-Life of 2 Minutes