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It is found that a reaction has the following rate equation: rate = k[PH3]1. The half-life of PH3 is 37.9 s at 120 oC.?

What fraction of the original sample of PH3 remains after 1 min.?

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  • HPV
    Lv 7
    7 years ago
    Favorite Answer

    The reaction is first order with respect to PH3. The concentration/time equation for a first order reaction is

    ln ([A]t/[A[o) = -kt

    k = 0.693 / t1/2 = 0.693 / 37.9 s = 0.0183 s^-1

    ln ([A]t/[A]o) = -(0.0183 s^-1)(60 s) = -1.10

    ([A]t/[A]o) = e^-1.10 = 0.334 = fraction of A still remaining at 1 min = 33.4%

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