Question

The combustion reaction of propane is described by the reaction. C3H8 + 5O2 → 4H2O + 3CO2. How many moles of O2 are required to generate 3 moles of CO2? A. 2.5 moles B. 3 moles C. 4 moles D. 5 moles

Answer 1

C₃H₈ + 5 O₂ → 4 H₂O + 3 CO₂

mole ratio based on balance equation of O₂ : CO₂ i s 5 : 3
C₃H₈ + 5 O₂ → 4 H₂O + 3 CO₂

∴ if moles of CO₂ = 3 moles

then moles of O₂ = (3 moles ÷ 3) × 5

= 5 moles (OPTION D)