A pure sample of tritium, ³H, was prepared and sealed in a container for a number of years. Tritium undergoes $\beta$ decay with a half-life of 12.32 years. How long has the container been sealed if analysis of the contents shows there are 5.25 mol of ³H and 6.35 mol of ³He present? A) 2.34 y B) 3.38 y C) 9.77 y D) 14.1 y E) 25.6 y

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Quizplus · Accepted Answer

The initial amount of tritium was 5.25 mol + 6.35 mol = 11.6 mol. Using the decay formula N = N0 * (1/2)^(t/T), where N is the remaining amount, N0 is the initial amount, t is time, and T is the half-life, we solve for t: 5.25 = 11.6 * (1/2)^(t/12.32). Solving this gives t ≈ 14.1 years.

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