Sodium-24 has a half-life of 15 hours. How much of a 20 mg sample would remain after two half-lives?

10 mg

2 mg

5 mg

0 mg

2 Answers

  • 5 months ago
    Favorite Answer

    1st 1/2 life 10 g

    2nd half life 5g

    3rd 1/2 life 2.5 g

    4th 1/2 life 1.25g


    Theoretically there is always a trace amount; it never reaches 0 g, . .

  • 5 months ago

    Half-life .....

    This question is in the ridiculously easy category. If you start with 20 mg, after one half-life you have 10 mg. That's the definition of "half-life." After a second half-life there will be 5 mg.

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