[huawey]

Hi everyone

Does anyone know how to transform a concentration stated in ppm to one stated in atoms/g?

e.g.
5 ppm of 238 U in . atoms/g

thank you in advance

[curiouscat]

238 gm ≡ 6.023E23 atoms
1 gm ≡ 2.531E21 atoms

5 atoms in 1E6
Hence ? in 2.531E21

I think the answer might be 1.265E16 atoms / gm

Not exactly right though since it will really depend on what's the rest other than U238

[huawey]

Hi, thank you for your replay.

238 is the atomic mass of the Uranium isotope.

btw: may I ask you why do you write gm instead of g?

[curiouscat]

btw: may I ask you why do you write gm instead of g?

Bad habit. 

[huawey]

Okay,
but why did you write 238 grams..??