The half-life of strontium - 90 is 28 years. How many grams of this nuclide in a 4.00 gram sample will remain after 112 years?

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Quizplus · Accepted Answer

The half-life of strontium-90 is 28 years, so after 112 years (which is 4 half-lives: 112 years / 28 years/half-life = 4 half-lives), the amount of strontium-90 will have halved 4 times. Starting with 4.00 grams, after one half-life, it would be 2.00 grams, then 1.00 gram, then 0.50 gram, and finally 0.25 gram after the fourth half-life.

The Half-Life of Strontium - 90 Is 28 Years