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..

## Answer this Question

## Related Questions

- chemistry - the longest lived radioactive isotope yet discovered is the beta-...
- chemistry - It takes 1 hour and 17 min. for a 1.000g sample of a certain isotope...
- Chemistry - I've figured out most of it. I'm not sure how to find the percentage...
- Chem - The decay constant for a radioactive isotope is 7.82 x 10-6 /y. What is ...
- Science chemistry - It takes 1 hour and 17 min. for a 1.000gsample of a certain ...
- math - A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. ...
- math - A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. ...
- math - A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. ...
- math - A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. ...
- math - A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. ...