state the formula unit mass and and why it is different from molecular mas
Answers
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.
The key difference between formula mass and molar mass is that, the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula while molar mass is the mass in grams of 1 mol of substance.