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The half-life of a radioactive isotope is three hours. If the initial mass of the isotope were 256 g, the mass of it in grams remaining undecayed after 18 hours would be:
ChemistryChemical KineticsJEE Main
Solution:
2500 Upvotes Verified Answer
The correct answer is: 4
t1/2=3 hours, n=T/t1/2=18/3=6

N = N 0 1 2 6
= 2 5 6 × 1 8 × 1 8 = 4 g ·
 

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