How Many Radioactive Atoms Are in a 6GBq Sample of 99mTc and What Is Its Mass

AI Thread Summary
To determine the number of radioactive atoms in a 6GBq sample of 99mTc, the decay constant (λ) is calculated using the half-life of 6 hours, resulting in λ = 0.115. This leads to an estimated number of nuclei (N) of approximately 5.21 × 10^17. The mass of the sample is then calculated using the formula mass = (no. nuclei * mass number) / Avogadro's number, yielding a mass of about 8.18 × 10^-7 kg. The discussion highlights the importance of the half-life in calculating both the number of atoms and the mass of the radioactive sample. Overall, the calculations demonstrate the relationship between radioactivity, decay constants, and mass in radioactive materials.
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Homework Statement



How many radioactive atoms are present in a sample of 6GBq of 99mTc and what is the approximate mass of the sample?

Homework Equations



A= λN
half life = ln2/λ
mass = (no.nuclei * mass number)/avorgado number
avogado = 6.023×10^23
half life = 6 hours

The Attempt at a Solution



worked out λ using the above half life (6 hours) and then N (no. nuclei). My problem is that we was not given the half life to beign with. Is there any other way of working it out without the half life ?
 
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N = 6GBq / λ λ= ln2 / half life λ = 0.693 / 6 λ = 0.115N = 6 GBq / 0.115N = 5.21 × 10^17mass = (no. nuclei * mass number) / avogado number mass = (5.21 × 10^17 * 99) / 6.023×10^23mass = 8.18 × 10^-7 kg
 

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