Answer:
21 mol of O₂ will react
Step-by-step explanation:
Based on the combustion of ethanol:
C₂H₅OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(g)
1 mole of ethanol, C₂H₅OH reacts with 3 moles of O₂
With this ratio of 1 mol C₂H₅OH / 3 moles O₂ we can solve the moles of O₂ that react with 7mol of ethanol:
7 mol C₂H₅OH * (3mol O₂ / 1 mol C₂H₅OH) =
21 mol of O₂ will react