Thallium-208 has a half-life of 3 minutes. How long will it take 60.0 g of thallium-208 to decay so that 15.0 g of the thallium-208 re

Question

Thallium-208 has a half-life of 3 minutes. How long will it take 60.0 g of thallium-208 to decay so that
15.0 g of the thallium-208 remains?
O3 min
O 6 min
O 9 min
O 11min Please explain how you got the answer?

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Huyền Thanh 5 months 2021-08-09T08:05:21+00:00 1 Answers 16 views 0

Answers ( )

    0
    2021-08-09T08:06:50+00:00

    Answer:

    The decay takes 6min

    Explanation:

    The decay of an isotope as Thallium-208 follows the equation:

    ln[A] = -kt + ln[A]₀

    Where [A] is amount of isotope after time t

    k is decay constant = ln 2 / t(1/2)

    [A]₀ is initial amount of the isotope

    Replacing:

    [A] = 15.0g

    k = ln 2 / t(1/2) = ln 2 / 3min = 0.23105 min⁻¹

    t = ?

    [A]₀ = 60.0g

    ln[A] = -kt + ln[A]₀

    ln[15.0g] = -0.23105 min⁻¹*t + ln[60.0g]

    -1.38629 = -0.23105 min⁻¹*t

    6min = t

    The decay takes 6min

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )