Homework Help: Chemistry

Posted by Val on Sunday, March 28, 2010 at 9:00pm.

Gallium65, a radioactive isotope of gallium, decays by first order-kinetics. The half-life of this isotope is 15.2 min. How long would it take for 7/8 of a sample of this isotope to decay?

15.2 min
30.4 min
45.6 min
48.0 min

I'm not sure how to do this. I initially tried by finding k for the values given for hte half life (ln2/15.2 min=k) and hten used k to find the value for when 7/8 was left over, but I keep getting t= 2.9 minutes which isn't right.

having trouble posting so I'm doing these in parts..

Chemistry - DrBob222, Sunday, March 28, 2010 at 9:07pm
k = 0.692/15.2 min

ln(No/N) = kt
I would just put in 8 for No and 1 for N --which says 7/8 is gone leaving 1/8).
ln(8/1) = kt and solve for t.

Answer this Question

Related Questions

Chemistry - If 30% of a sample of radioactive isotope decays in 24 hrs, what is ...
Chemistry - As a sample of the radioactive isotope 131 I decays, its half-life a...
chemistry - the longest lived radioactive isotope yet discovered is the beta-...
math - How do I set-up/solve this problem? Please help me. The half-life of the ...
calculus - How do I set-up/solve this problem? Please help me. The half-life of ...
chemistry - It takes 1 hour and 17 min. for a 1.000g sample of a certain isotope...
Science chemistry - It takes 1 hour and 17 min. for a 1.000gsample of a certain ...
chemistry - A radioactive sample contains 2.45g of an isotope wiht a half life ...
Chemistry - Tc-99 is a radioactive isotope that decays by beta emission and is ...
Chemistry - A 208 g sample of sodium-24 decays to 13.0 g of sodium-24 within 60....

For Further Reading

First Name:
School Subject:
Answer: