Mass of Nuclide Remaining After a Fraction of a Half-Life

AI Thread Summary
To determine the mass of CaCO3 needed for an experiment with 47Ca, which has a half-life of 4.53 days, one must account for the time it takes for delivery. The calculation shows that 50 hours corresponds to approximately 0.4599 half-lives. After applying the decay formula, the remaining mass of 47Ca is calculated to be 0.727 of the original amount needed, leading to a required mass of 4.47 μg. However, there is confusion regarding the correctness of this answer, suggesting a need for careful review of the problem statement. The discussion emphasizes the importance of accurately interpreting the question to avoid errors in calculations.
jzwiep
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Homework Statement



You want to do an experiment using 47Ca (half-life=4.53 days). You will need 3.25 μg of the nuclide. What mass of CaCO3 (100% enriched in 47Ca) must you order if it will take 50 hours to be delivered to you from the nuclear facility where it is prepared?

Homework Equations





The Attempt at a Solution



4.53 days x 24 hrs/day = 108.72 hrs

50/108.72 = 0.4599 half-lives

(1/2)^0.4599 = 0.727

3.25 μg / 0.727 = 4.47 μg

Am I doing something wrong? All the ways I've seen to do this type of problem lead me to the same answer, but it says it's incorrect.
 
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jzwiep said:

Homework Statement



You want to do an experiment using 47Ca (half-life=4.53 days). You will need 3.25 μg of the nuclide. What mass of CaCO3 (100% enriched in 47Ca) must you order if it will take 50 hours to be delivered to you from the nuclear facility where it is prepared?

...


Am I doing something wrong?
All the ways I've seen to do this type of problem lead me to the same answer, but it says it's incorrect.

I don't think so but you haven't finished, read the question carefully!
 
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