The Balance Chemical equation for said reaction is as follow,
C₂H₆ + 3.5 O₂ → 2 CO₂ + 3 H₂O
Or,
2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O
According to equation,
2 moles of Ethane react completely with = 7 moles of Oxygen
So,
4.20 moles of Ethane will react with = X moles of Oxygen
Solving for X,
X = (4.20 mol × 7 mol) ÷ 2 mol
X = 14.7 moles of Oxygen
Result:
14.7 moles of Oxygen are required to react with 4.20 moles of Ethane for complete reaction.