J.R. S. answered 08/24/21
Ph.D. University Professor with 10+ years Tutoring Experience
From your previous question, and my previous answer to your previous question, we have the following:
Let's turn the word equation into a chemical equation and balance it.
hydrogen sulfide (g) = H2S(g)
oxygen (g) = O2(g)
water (l) = H2O(l)
sulfur dioxide = SO2(g)
2H2S(g) + 3O2(g) ==> 2H2O(l) + 2SO2(g) ... balanced equation
From the balanced equation we see TWO moles of H2O are formed from THREE moles of O2 when H2S is present in excess. Using this mole ratio and the fact that we have 28.0 g of O2, we proceed as follows:
28.0 g O2 x 1 mol O2 / 32 g O2 = 0.875 mols O2 present
0.875 mols O2 x 2 mols H2O / 3 mols O2 = 0.583 mols H2O formed
0.583 mols H2O x 18 g H2O / mol H2O = 10.5 g H2O formed