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The half life of thallium-201 is 21.5 hours. We have 85 g of thallium-201 how many grams will be left after 10 half-lives?

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  • 2 months ago
    Favourite answer

    A = A₀ (1/2)^(t/h)

    A = 85g (1/2)^10

    A = 0.0830078125g

    3 sigfigs: 8.30 x 10^-2 g

    • Dr W
      Lv 7
      2 months agoReport

      how many sig figs does 85 have?  why 3 sig figs in your final answer?

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  • Anonymous
    2 months ago

    I don't know, I hope I helped you Ok?

    Good afternoon and stay with God 🙏😉

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  • Dr W
    Lv 7
    2 months ago

    that's an AMAZING sample of Thallium you have there Kalayvonna.  Because

    .. (1) the half life of Tl-201= 72.9 hr (according to literature)

    .. (2) Tl-201 is not naturally occurring.  it's produced in cyclotrons at point

    .. . .. .of use (or nearby point of use) at a rate of about 1 picogram / μ AH

    So how you would have an 85.g sample of Tl-201 with a half life = 21.5hrs is beyond me!  Oh wait.. this is another one of those make believe questions that some instructors throw together without much thought.  I get it now!

    ***********

    <sigh>.. use this equation

    .. At = Ao * (1/2)^(t / half life)

    .. At = 85.g * (1/2)^10

    .. At = 0.083g

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  • 2 months ago

    85 x (1/2)^10 =>

    85 X 0.000976...

    0.08388 g

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  • Zirp
    Lv 7
    2 months ago

    2¹⁰=1024, so a little less than 1/1000

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  • 2 months ago

    (85 g) x (1/2)^10 = 0.083 g

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  • Anonymous
    2 months ago

    85 g * 0.5^10

    Not very much.

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