Theoretical yield

Question

Liquid octane (CH3(CH2)6CH3) reacts with gaseous oxygen gas (o2) to produce gaseous carbon dioxide (CO2) and Garoua water H2O what is the theoretical yield of carbon dioxide formed from the reaction of 3.43g of octane and 18.2 g of oxygen gas?

Answer 1

Molar mass octane (C₈H₁₈) = 114.2 g / mol

Molar mass carbon dioxide (CO₂) = 44.0 g / mol

Molar mass oxygen (O₂) = 32.0 g / mol

2C₈H₁₈ + 25O₂ ==> 16CO₂ + 18H₂O ... balanced equation for combustion of octane

moles C₈H₁₈ = 3.43 g x 1 mol / 114.2 g = 0.0300 mols

mols O₂ = 18.2 g x 1 mol / 32 g = 0.5688 mols

Since 2 mols C₈H₁₈ react with 25 mols O₂, this makes C₈H₁₈ the limiting reactant and as such, it will determine how much CO₂ will be formed.

Theoretical yield of CO₂ = 0.0300 mols C₈H₁₈ x 16 mol CO₂ / 2 mol C₈H₁₈ x 44.0 g / mol = 10.6 g CO₂