Question

Zinc blende [Zns] is roasted in air. CALCULATE:

the number of moles of sulphur dioxide liberated by 776gm of zns

Answer 1

2ZnS + 3O₂ → 2ZnO + 2SO₂

Molar mass of ZnS = 97.4 g/mol

Molar mass of SO₂ = 64 g/mol

Now, according to balanced chemical equation,

(2x97.4) = 194.8 g of ZnS gives (2x64) = 128 g of SO₂

So, 776 g of ZnS will give (128x776)/194.8 = 509.9 g of SO₂

64 g of SO₂ = 1 mole

509.9 g of SO₂ = (509.9/64) = 7.97 mole of SO₂.