Posted by **Trixie ** on Friday, April 16, 2010 at 5:04pm.

A radioactive sample contains 3.25 1018 atoms of a nuclide that decays at a rate of 3.4 1013 disintegrations per 26 min.

(a) What percentage of the nuclide will have decayed after 159 d?

%

(b) How many atoms of the nuclide will remain in the sample?

atoms

(c) What is the half-life of the nuclide?

days

I have a general idea of how to solve this but keep getting the incorrect answer...I've tried a few different ways so I'm not sure where I'm going wrong. My initial attempt was to convert days into minutes for my calculations. I used the equation N'=Ne^-kt where I calculated k to be the rate given (over minutes). I don't need the answers per se...I think once I know how to correctly approach this I should be fine in figuring them out...Thanks

- chemistry -
**Trixie **, Friday, April 16, 2010 at 5:08pm
Oh and when I try to put this into my calculator I get 0... sorry if I am not catching on fast enough for some....I worked graveyard last night and Haven't slept in over 35 hours...

- chemistry -
**Trixie **, Friday, April 16, 2010 at 5:18pm
Another attempt I made gave me relatively "reasonable" answers...but still doing something wrong.

I converted the minutes to days and used that in the rate to find k via k= rate/N ; N being 3.25E18 atoms. this calculated k to be .00145.

I plugged this into N'=Ne^-kt....can someone please point out what I am doing wrong?

- chemistry -
**DrBob222**, Friday, April 16, 2010 at 5:36pm
My recommendation is

a. go to bed for some rest.

b. take fewer classes next quarter/semester/year.

- chemistry -
**Trixie **, Friday, April 16, 2010 at 6:27pm
Sleep is a bit of a luxury.....unfortunately I'm one of those students that doesn't have an option of taking a lighter load or working less....luckily I graduate in a few weeks. In the meantime I need to finish these problems so that I can go to bed....but they are due at 11pm tonight and if I go to sleep before completing them I know I won't wake up.

- chemistry -
**Trixie **, Friday, April 16, 2010 at 6:30pm
Could you please just explain what I am doing wrong so that I can know how to approach these problems? I appreciate the advice and am well aware I need to go to bed...but I have to get these finished and my professor is out of town attending a memorial service and unable to answer emails until Sunday...

## Answer this Question

## Related Questions

- Chemistry - Q1. The blood volume in a cancer patient was measured by injecting 5...
- Chemistry - A radioactive sample contains 3.25 1018 atoms of a nuclide that ...
- Chemistry - A 71 mg sample of a radioactive nuclide is administered to a patient...
- chemistry - a certain radioactive nuclide has a half life of 5.00 hour. Calcuate...
- Chem - If a sample of the radioactive nuclide 139Cs has an activity of 0.0730 Ci...
- college - if a sample of the radioactive nuclide 139cs has an activity of 0.0730...
- Chemistry - The nuclide 38cl decays by beta emission with a half life of 40min...
- chem - Nuclide X has decay constant 1.08 h-1. It can decay in 2 branches, to ...
- Chemistry - A 50.6 mg sample of sodium perchlorate contains radioactive chlorine...
- Chemistry - It took 109.8 years for a 300.0 mg sample of an unknown radioactive ...

More Related Questions