If 2.72 mol of ethane (C2H6) undergo combus- tion according to the unbalanced equation C2H6+O2→CO2+H2O, how many moles of H2O is required?
Roger the Mole
No H2O is required. H2O is produced. 2 C2H6 + 7 O2 → 4 CO2 + 6 H2O (2.72 mol C2H6) x (6 mol H2O / 2 mol C2H6) = 8.16 mol H2O produced (2.72 mol C2H6) x (7 mol O2 / 2 mol C2H6) = 9.52 mol O2 required
Some Body: Balancing
Balancing: 2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O Stoichiometry: 2.72 mol C₂H₆ * (6 mol H₂O / 2 mol C₂H₆) = 8.16 mol H₂O
0 moles, it's a trick question Water isn't required by the reaction, it's produced by the reaction. For the amount of water produced, moles of water = 2.72 moles ethane * 3 moles H2O / mole ethane