How formula unit mass is different from molecular mass?

Question

1 Answer

answered Oct 16, 2020 by Jaanvi01 (56.3k points)
selected Oct 19, 2020 by Kaanta

Best answer

Formula unit mass	Molecular mass
Formula unit mass of a substance is the sum of the atomic masses of all atoms in a formula unit of a compound.	The molecular mass of a substance is the sum of a substance is the sum of atomic masses of all the atoms in a molecule of the substance.
It is used for those substances whose constituent particles are ions.	It is used for those substances whose constituent particles are molecules.
The formula mass is the sum of all the molecules in the compound.	The molecular mass remains the same even if millions of molecules are added.
Example: The formula mass for sodium chloride is: NaCl, 23 + 35.5 = 58.5 amu.	Example: The molecular mass of CO₂ = 1 x Atomic Mass of Carbon + 2 x Atomic Mass of oxygen =12 + 2 x 16 =12 + 32 = 44u.