Question

What is the difference between gram and unified mass for e.g 28u and 28g and how to find volume occupied by them?

Answer 1

Gram atomic mass is the mass of one mole of an element expressed in grams.
1 amu/atom = 1 g / mole of atoms
So, mass of one atom of carbon is 12 amu
And mass of one mole of carbon atoms is 12g.
Therefore, unified mass is used for expressing mass of single atom whereas gram is used for expressing mass of 1 mole of an element.
volume can be find out from the formula density = mass / volume, if density is given as we know the mass of atom. The only thing unknown to find out the volume is density.