A solid sample is 81.0 g sodium per 1,000,000. g substance, and contains 1.92 × 10 ^21 sodium atoms, calculate the mass (g) of the sample.
mols Na = 1.92E21/6.023E2 = ?
g Na = mols x atomic mass = ? = about 0.07 but you need to do it more accurately.
Then 0.07/x = 81E-6
Solve for x.
