Calculate the molecular mass of sulphuric acid `(H_(2)SO_(4))`.
(Given : Atomic masses : `H = 1u , S = 32 u , O = 16 u`).

Explanation

The molecular formula of sulphuric acid is `H_(2)SO_(4)`. This formula shows that one molecule of suphuric acid `(H_(2)SO_(4))` contains 2 atoms of hydrogen, 1 atom of suphur and 4 atoms of oxygen. So, the molecular mass of `H_(2)SO_(4)` will be equal to the sum of the masses of ` 2` hydrogen atoms, 1 sulphur atom and 4 oxygen atoms. Knowing that the atomic mass of hydrogen is 1 u, of sulphur is 32 u and that of oxygen is 16 u, the molecular mass of sulphuric acid can be calculated as follows :
Molecular mass of `H_(2)SO_(4) = underset("atoms")("Mass of " 2H) + underset("atoms")("Mass of S") + underset("atoms")("Mass of 4 'O'")`
`= 2 xx 1 + 32 + 4 xx 16`
`= 2 + 32 + 64`
`= 98 u`
Thus, the molecular mass of sulphuric acid is `98 u`.
Before we conclude the discussion on formulae, it will be good to note of significance of the chemical formula of a substance which is given below.