# If a radioactive sample starts with 100 g, how many grams of the original substance will be left after 5 half lives? show work please?

20 g

50 g

3.125 g

12.5 g

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- ChemTeamLv 74 months agoFavourite answer
(1/2)^5 = 0.03125 (decimal amount remaining after 5 half-lives)

100 g * 0.03125 = 3.125 g remaining after 5 half-lives

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