Question

molecular mass is a realeative quantity

Answer 1

Molecular mass is also calledmolecular weight. Because the mass is relative to carbon-12, it's more correct to call the value "relative molecular mass". A related term ismolar mass, which is the mass of 1 mol of a sample. Molar mass is given in units of grams.

Answer 2

The molecular mass (m) is the mass of a given molecule: it is measured in atomic mass units (amu) or daltons (Da). Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element.