Chemical Forums
Specialty Chemistry Forums => Nuclear Chemistry and Radiochemistry Forum => Topic started by: sweetdaisy186 on August 13, 2005, 08:07:21 PM
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Hey guys!
I am having a very stuff time understand nuclear chemistry and half-life. The problem is:
The half-life of iodine-131 is 8.04 days. Suppose we follow the activity of a sample of iodine-131 while it falls to 10% of its inital value. (a) Estimate how long this will take, and (b) calculate a more exact value of the time required
When they say that the half-life is 8.04 days it means that is how long before half of the iodine 131 disappears right? So, should I take 10 percent of 8.04 for parts and b?
Any hints would be greatly appreciated!!!
Thanks!
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you may refer to this similar discussion thread here:
http://www.chemicalforums.com/index.php?board=27;action=display;threadid=4094
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Since this is a first order rxn, the integrated rate law gives ln(Nt/N0)=-kt
k=ln2/half life=0.08621
Nt/N0=10%=0.1
ln0.1=-0.08621t
t=26.70830188days
how do you estimate the time without any calculation?