# chemistry

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caffeine has a half-life of 4.6 hours in the human body.. How long would it take 125 milligrams tritium to decay to 22 milligrams?

• chemistry -

Pray tell what does caffeine have to do with tritium?
For tritium,
k = 0.693/t1/2
You will need to look up the half-life of tritium unless that is the "caffeine" half-life.
Substitute k into the below equation.
ln(No/N) = kt
Nl = 125
N = 22
k = from above calculation.
t = time. Solve for this. Note that the unit for time and the unit for half-life must be the same.

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