Answer:
8 should be placed in front of SO₂.
Explanation:
The easiest way to solve this question is by writing the entire balanced equation:
4FeS₂ + 11O₂ -> 2Fe₂O₃ + 8SO₂
We can achieve this by first balancing the Fe, then S, and finally the O.
We can also double check our answer by counting the number of each element on both sides:
-Reactants: 4 Fe, 8 S, 22 O
-Products: 4 Fe 8 S, 22 O
Since they match, our equation is balanced, and the coefficient in front of SO₂ is 8.
