Question

. Define formula mass and how does it differs from molecular mass

Answer 1

Molecular mass is the mass of a given molecule or compound but now the clinch here is that it remains neutral despite the presence of zillions of molecules. For ex: Molecular mass of CO2 = 12*1 + 16*2=44.

2.But, now the formula mass is something different. IT IS THE MOLECULAR MASS OF THE WHOLE COMPOUND CONTAINING X NO. OF MOLECULES OF THAT COMPOUND. Let me clarify it with example: Like we have to find the formula mass of 10Na2SO4.H2O= 10[23*2+32+16*4+2*1+16*1] = 10*180= 1800.

Answer 2

Hi friend,

Formula mass can be defined as the sum of the atomic weights of the constituent atoms in an electrovalent compound.

Difference between formula mass and molecular mass is as follows:-
1.Formula mass can be defined as the sum of the atomic weights of the constituent atoms in an electrovalent compound whereas molecular mass is the sum of the atomic masses of all the atoms present in a molecule of a substance.

2.The term formula mass is generally used for electrovalent compounds whereas molecular mass is used for covalent compounds.

3.Example:- Molecular mass of sucrose is 342.2965 g/mol whereas formula mass of sucrose is 342.34 amu.