How Many molecules Of sodium are contained in 2 L Of sodium dichromate? The density Of sodium dichromate is 3.7 g/ml

Answer 1

This is a solid, not a solution and we assume the solid is packed in the container with no "empty" spaces.
3.7 g/mL x 2000 mL = 7,400 grams Na2Cr2O7.

mols Na2Cr2O7 = grams Na2Cr2O7/molar mass Na2Cr2O7.

mols Na2Cr2O7 x 6.02E23 = molecules of Na2Cr2O7.

Atoms Na = 2 x # molecules Na2Cr2O7.