
Answer:
The answer to your question is 0.4 moles of Oxygen
Explanation:
Data
Octane (C₈H₈)
Oxygen (Oâ‚‚)
Carbon dioxide (COâ‚‚)
Water (Hâ‚‚O)
moles of water = ?
moles of Oxygen = 1
Balanced chemical reaction
          C₈H₈  +10O₂  ⇒  8CO₂  +  4H₂O
       Reactant   Element   Products
          8         C         8
          8         H         8 Â
          20         O        20 Â
Use proportions to solve this problem
         10 moles of Oxygen ----------------- 4 moles of water
          1 mol of Oxygen   ------------------ x
          x = (4 x 1) / 10
          x = 4 / 10
          x = 0.4 moles of water