Chemistry

Question

The half life of protactinium 234 in its ground state is 6.69 h. What fraction of a given amount remains after 26.76 h

2 Answer

  • Answer:

    ¹/₁₆

    Step-by-step explanation:

    The half-life of Pa-234 (6.69 h) is the time it takes for half the Pa to decay.  

    After one half-life, half (50 %) of the original amount will remain.  

    After a second half-life, half of that amount (25 %) will remain, and so on.  

    We can construct a table as follows:  

      No. of                  Fraction

    half-lives   t/(h)   remaining

         2         13.38            ¼    

         3        20.07            ⅛

         4        26.76             ¹/₁₆

         5        33.45             ¹/₃₂

    We see that 26.76 h is four half-lives, and the fraction of Pa-234 remaining

    is ¹/₁₆.  

  • your answer is 1/16

    because once you multiply the first two stated numbers you divide it by the last to get your answer

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