Question

Why there is a difference in total number of atoms of each element in

196g of sulphuric acid and 196 amu of sulphuric acid?

Answer 1

196g means relative molecular mass.

Molecular mass or molecular weight is the mass of a molecule.

It is calculated as the sum of the atomic weights of each constituent element multiplied by the number of atoms of that element in the molecular formula.

The relative molecular mass of sulfuric acid can be calculated by adding the relative atomic masses of the elements in the compound:

go to the periodic table and find the molar mass (Mm) of the elements found in H2SO4.

H = 1.00794g/mol

S = 32.064g/mol

O = 15.9994g/mol

H2SO4 = 2(1.00794) + 32.064 + 4(15.9994) = 98.07748g/mol .

Here 196 grams is given which means 196/98 = 2 mols. 1 mole contains avogadro number of particles(Na). Here there are 2Na sulfuric acid molecules. One molecule of sulphuric acid contains 7 atoms

therefore total no.of atoms in 196 gm of H2SO4 = 7×Na.

amu of Sulphuric acid means the mass of each atom of Sulphuric acid .( actual mass).An atomic mass unit (symbolized AMU or amu) is defined as precisely 1/12 the mass of an atom of carbon-12.This is approximately 1.67377 x 10 -27 kilogram (kg), or 1.67377 x 10 -24 gram (g).
​​​​​​AMU of Sulphuric acid is 98 amu. 196 means two molecules of sulSulphu acid(196/98=2).
Thatis 14 atoms.
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