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

Answer 1

your answer is 1/16

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

Answer 2

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.