A large quantity of sulfur is obtained industrially from “sour” natural gas containing hydrogen sulfide. First, hydrogen sulfide is burned in air to give sulfur dioxide. Second, the SO₂ produced reacts with additional H₂S to give elemental sulfur. 

2 H₂S(g) + 3 O₂(g) → 2 SO₂(g) + 2 H₂O(g)     (1) 

2 SO₂(g) + 2 H₂S(g) → 3 S(l) + 2 H₂O(g)         (2) 

Calculate the volume of H2S at STP that is required to produce 1.00 kg of sulfur.