What is the half-life of radon-222 if a sample initially contains 120.0 mg and only 18.1 mg after 12.3 days?

Explanation:

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In this case, since the kinetics of radioactive decay in terms of initial and final amounts, elapsed time and half-life is:

we can compute the half time as shown below:

Plugging in the known amounts and elapsed time, we obtain:

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water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.