How to find the mass of a compound given the half life and activity?

In summary, the formula for finding the mass of a compound using half life and activity is: Mass = (Activity * Half Life) / (ln2 * Decay Constant). The decay constant can be determined by dividing the natural logarithm of 2 by the half life of the compound. It is recommended to use consistent units of measurement for activity and half life, but as long as the units are consistent, the formula will still work. This method can be used for compounds with multiple radionuclides as long as the activity and half life values correspond to the specific radionuclide being measured. The initial amount of the compound does not need to be taken into account when calculating the mass.
  • #1
ununseptium
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0

Homework Statement


What mass of Na2 SO4 has an activity of 10.0 mCi? Sulfur-38 has an atomic mass of 38.0 and a half life of 2.87h


Homework Equations



Half life= 0.693/ k

Rate= kN

The Attempt at a Solution


I'm not sure where to begin the sulfur-38 part is throwing me off
All I need is some hint as to where to begin
 
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  • #2
What 10 mCi means?

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methods
 

1. What is the formula for finding the mass of a compound using half life and activity?

The formula is: Mass = (Activity * Half Life) / (ln2 * Decay Constant)

2. How do I determine the decay constant for a compound?

The decay constant can be determined by dividing the natural logarithm of 2 by the half life of the compound.

3. Can I use any unit of measurement for activity and half life?

It is recommended to use consistent units of measurement for activity and half life, such as becquerels (Bq) and seconds (s) respectively. However, as long as the units are consistent, the formula will still work.

4. Can I find the mass of a compound with multiple radionuclides using this method?

Yes, as long as the activity and half life values used in the formula correspond to the specific radionuclide being measured.

5. Do I need to take into account the initial amount of the compound when calculating the mass?

No, the formula only requires the activity and half life of the compound to calculate the mass, so the initial amount is not necessary.

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