Posted by **brittany** on Thursday, May 12, 2011 at 5:23pm.

If you accidentally spill phosphorus-32 onto your shoe, how long would it take before 99.9 of the radioactive material has decayed so that you can safely wear the shoes again?

- chemistry -
**DrBob222**, Thursday, May 12, 2011 at 5:33pm
Is that 99.9% or some other value? You have no units.

k = 0.693/t_{1/2}

Substitute and solve for k, then substitute k into the equation below.

ln(No/N) = kt

No = some convenient number like 100.

N will be 0.1 if 99.9% of the atoms have decayed.

k from above.

Solve for t (in the same units as the half life is given).

## Answer This Question

## Related Questions

- Chemistry - The half-life of phosphorus-32 is 14.26 days. The decay constant is ...
- Business Mgmt. - I need to write a paragraph on Identifying the demographics and...
- chemistry - if you start with 100mg of radioactive material that has a half life...
- Math - There are four brown shoes and 10 black shoes on the floor. your puppy ...
- Science - A material has 32 atoms in all; 24 decayed and the rest undecayed. If ...
- chemistry - A particular radioactive substance has a half-life of 4 minutes. How...
- Math - How do I solve this if there is no equation to this 1. The population of ...
- Physics - You are sitting in your car at a traffic light at the foot of a 200 ft...
- math - A men's shoe store uses a markup rate of 115% on its most popular brands ...
- chemistry - Radioactive waste is difficult to dispose of due to the long time ...

More Related Questions