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Svetradugi [14.3K]
3 years ago
14

Assume you began with 10 g of a radioactive parent isotope. How many grams of parent isotope will be present in the sample after

2 half-lives?
Biology
2 answers:
Anna11 [10]3 years ago
5 0

Answer:

2.5 grams

Explanation:

In radioactive decay, one half-life is the time it takes for half of the radioactive sample to decay. So if it takes two hours (for example) for a sample to go from 8 grams to 4 grams, then one half-life has passed (since half the sample has decayed), and the half-life is two hours.

<u>Calculation:</u>

2 half-lives = sample halved twice

10 grams / 2 = 5 grams (one half-life has passed)

5 grams / 2 = 2.5 grams (two half-lives have passed)

9966 [12]3 years ago
3 0
2.5g

10÷2=5
5÷2=2.5

everytime it completes a half life, you divide the number by two
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