A 9.9-g sample of iodine-131 is stored for exactly 3 weeks.If the decay constant is 0.0861 day^-1,what mass of the isotope remains?

Question

Quizplus · Accepted Answer

The equation for radioactive decay is given by:

N(t) = N0 e^(-λt)

Where N(t) is the number of radioactive nuclei at time t, N0 is the initial number of radioactive nuclei, λ is the decay constant, and t is the time elapsed.

To find the amount of iodine-131 remaining after 3 weeks, we need to calculate the decay factor e^(-λt) and multiply it by the initial mass:

e^(-0.0861 day^-1 * 21 days) ≈ 0.159

0.159 * 9.9 g ≈ 1.57 g

Therefore, the mass of iodine-131 that remains after 3 weeks is approximately 1.6 g.

The closest option is C.

A 99-G Sample of Iodine-131 Is Stored for Exactly 3 Weeks