Question

He radioisotope radon-222 has a half-life of 3.8 days. how much of a 65-g sample of radon-222 would be left after approximately 15 days?

Answer 1

Given: Half life of Rn = 3.8 days
Therefore in 15 days, system crosses 15/3.8 = 3.94 ≈ 4 half-life

Now, Initial amount of Rn = 65 g

∴ Amount of Rn left after 4 half life i.e. 15 days =
`(65)/(2^4)` = 4.06 g