Molecular Weight: It is the relative weight of a molecule of an element or a compound as compared to 1/12 of the mass of one atom of C-12.
Thus molecular weight is also a ratio and hence has no units. It is expressed in amu
Mol. wt. = \(\frac{\text{Weight of one one molecule of the substance}}{1/12 \,\times \text{ Weight of one atom of C-12}}\)
Actual weight of one molecule = Mol. wt. x 1.66 x 10-24 g
Molecular weight of a substance is the additive property and can be calculated by adding the atomic weights present in one molecule.
