Question

differentiate between formula unit mass and molecular mass

Answer 1

There is a cyclopean difference between molecular mass and formula mass.

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.

So, it is pretty clear that formula mass is ‘x’ times the molecular mass of that compound.

Answer 2

ITS A VERY COMMON DOUBT.. THE NAME ITSELF SUGGETS THAT FORMULA UNIT MASS IS THE FORMULA UNIT OF A COMPOUND AND MOLECULAR MASS IS EXPRESSED IN u and it's an amount..