The half-life of sodium-24 is 15.0 hours.What percentage of a sample of sodium-24 remains after 75.0 hours?

Question

Quizplus · Accepted Answer

Since the half-life of sodium-24 is 15.0 hours, we can calculate the number of half-lives that occur in 75.0 hours:

75.0 hours ÷ 15.0 hours/half-life = 5 half-lives

This means that the amount of sodium-24 remaining after 75.0 hours will be:

(1/2)^5 = 1/32 = 0.03125

So, the percentage of the sample that remains after 75.0 hours is:

0.03125 × 100% = 3.13%

Therefore, the best choice is B.

The Half-Life of Sodium-24 Is 15