Posted by Aidan on Monday, August 29, 2011 at 11:14pm.
Naturally occurring cobalt consists of only one isotope, cobalt59, whose relative atomic mass is 58.9332. A synthetic radioactive isotope of cobalt60, relative atomic mass 59.9338, is used in radiation therapy for cancer. A 1.8155 sample of cobalt has an apparent "atomic mass" of 58.9901.
FIND THE MASS OF COBALT60 IN THIS SAMPLE.
I DON'T KNOW WHERE TO START, I TRIED DOING CONVERSION FACTORS BUT I CANT GET A REASONABLE MASS.
- PLEASE HELP ME! CHEMISTRY - DrBob222, Monday, August 29, 2011 at 11:53pm
Let x = fractional abundance Co60
1-x = fractional abundance Co59
(Note that as percentages that will be x% and 100%-x%). Then
x(atomic mass Co60) + (1-x)(atomic mass Co59) = 58.8901
Solve for x and 1-x will give you the fractinal abundances of Co59 and Co60. Then fraction * 1.8155g = grams Co60 or Co59 depending upon which fraction you use. Post your work if you get stuck.
- PLEASE HELP ME! CHEMISTRY - LAUREN, Tuesday, August 30, 2011 at 12:06am
(x)(59.9338) +(1-x)(58.9332) =(58.9901)
0.0569/0.9431 X 1.8155g = .10953grams
Is that right?? It looks like i did it wrong.
- PLEASE HELP ME! CHEMISTRY - Aidan, Tuesday, August 30, 2011 at 12:16am
OH wait, do we do
0.0569 X 1.8155g = 0.103g ?
- PLEASE HELP ME! CHEMISTRY - Aidan, Tuesday, August 30, 2011 at 12:25am
- PLEASE HELP ME! CHEMISTRY - DrBob222, Tuesday, August 30, 2011 at 12:48am
Everything looks ok except where you converted to percent (which the problem didn't ask for). x = 0.0560 = Co60 abundance which is 5.60% if yu want to convert to percent.
Answer This Question
More Related Questions
- Chem - Naturally occurring cobalt consists of only one isotope, cobalt59, whose ...
- Chemistry - Naturally occurring cobalt consists of only one isotope, 59Co, whose...
- chemistry - Naturally occurring cobalt consists of only one isotope Co59 whose ...
- Chemistry - 1)Naturally occuring boron is made up of 20% by mass of 10B isotope ...
- Chemistry - 1. A hypothetical pure element consists entirely of two isotopes. ...
- Chemistry - Silver has an average atomic mass of 107.9 u and is known to have ...
- chemistry - Copper has two naturally occurring isotopes. Cu-63 has a mass of 62....
- Chemistry - Naturally occurring boron is 80.20% boron-11 (of atomic mass 11.01 ...
- chemistry - Calculate the atomic mass of naturally occurring molybdenum (Mo) ...
- chemistry - Naturally occurring silicon exists as 3 isotopes: 28Si, 29Si, and ...