the combstion of ZnS in excess oxygen gives ZnO and SO₂ as the products.
hence the equation should be;
ZnS(s) + O₂(g) →ZnO(s) + SO₂(g)
At the left hand side: At the right hand side:
number of Zn atoms = 1 number of Zn atoms = 1
number of S atoms = 1 number of S atoms = 1
number of O atoms = 2 number of O atoms = 3
Hence the balanced equation is;
2ZnS(s) + 3O₂(g) →2ZnO(s) + 2SO₂(g)