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AnnZ [28]
3 years ago
5

Fluorine-21 has a half life of approximately 5 seconds. You have 340 grams, what fraction of the original nuclei would remain af

ter 20 seconds?
Chemistry
1 answer:
madreJ [45]3 years ago
7 0
The half life equation is -->P(t) = Pi (0.5) ^ (t/c)
c is equal to the element to reach its half-life (5 seconds)t is equal to the duration of time the element is expose to (20 seconds)Pi is the initial amount (340)0.5 is the base of this exponential function to represent half-life.P(t) is the expression for the function of time

P(20) = 340 (0.5)^20/5P(20) = 340 (0.5) ^4P(20)= 21.25 grams
Fraction = P(t)/Pi              = P(20)/Pi              =21.25/340              =1/16
Therefore, when given 20 seconds, 340 grams of Fluorine-21 will degrade to 21.25 grams OR 1/16 of its original mass.
Hope this method helps! (This is my answer btw, I think you may have accidentally posted twice?)
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