Question

Calculate the mass percent of different elements present in sodium sulphate (Na₂SO₄).

Answer 1

The molecular formula of sodium sulphate is Na₂SO₄

Molar mass of Na₂SO₄ = [(2 × 23.0) + (32.066) + 4 (16.00)] = 142.066 g

${\displaystyle \text{Mass percent of an element}=\frac{\text{Mass of the element in the compound}}{\text{Molar mass of the compound}}\times 100}$

∴ Mass percent of sodium :-

${\displaystyle =\frac{46.0 \text{g}}{142.066 \text{g}}\times 100}$

 = 32.379

= 32.4%

Mass percent of sulphur :-

${\displaystyle =\frac{32.066 \text{g}}{142.066 \text{g}}\times 100}$

= 22.57

= 22.6%

Mass percent of oxygen :-

${\displaystyle =\frac{64.0 \text{g}}{142.066 \text{g}}\times 100}$

= 45.049

= 45.05%