Answer:
% Yield = 81.4%
Explanation:
Based on the reaction:
C₈H₁₈ + 25/2O₂ → 8CO₂ + 9H₂O
1 mole of C₈H₁₈ reacts with 25/2 moles of O₂ to produce 8 moles of CO₂
To solve this question we must, as first, find limiting reactant. With limiting reactant we can find theoretical yield of CO₂. Percent yield is defined as:
% Yield = Actual yield (917g CO₂) / Theoretical Yield * 100
For a complete reaction of 4.00 moles of C₈H₁₈ are required:
4.00moles C₈H₁₈ * (25/2 moles O₂ / 1mol C₈H₁₈) = 50.0 moles of O₂
As there are just 40.0 moles, O₂ is limiting reactant
The theoretical yield of CO₂ from 40.0 moles of O₂ is:
40.0 moles O₂ * (8 moles CO₂ / 25/2 moles O₂) = 25.6 moles of CO₂
As molar mass of CO₂ is 44.01g/mol:
25.6 moles of CO₂ * (44.01g / mol) = 1126.7g of CO₂ is theoretical yield
And percent yield is:
% Yield = 917g / 1126.7g * 100
% Yield = 81.4%
