Question

The radioisotope radon-222 has a half life of 3.8 days. How much of a 73.9 g sample of radon-222 would be left after approximately 23 days?

Answer 1

Use the 1st order decay equation `C_("final") = C_"initial" e^(-kt)`
=> `C_("final")` = 1.11 grams Rn-222 after 23 days.

Explanation:

All radio decay is 1st Order Kinetics.