Final answer:
The mass of carbon dioxide formed when 9.25 liters of benzene is burned at STP is 108.92 g, calculated using stoichiometry and the molar volume at STP.
Step-by-step explanation:
To calculate the mass of carbon dioxide (CO₂) formed from burning benzene (C₆H₆) at STP, we use stoichiometry based on the balanced chemical equation for the combustion of benzene:
2 C₆H₆ (l) + 15 O₂ (g) → 12 CO₂ (g) + 6 H₂O (g)
First, we convert the given volume of benzene to moles using the molar volume at STP (22.414 L mol⁻¹):
Moles of C₆H₆ = 9.25 L / 22.414 L mol⁻¹ = 0.4125 moles
From the stoichiometry of the balanced equation, the mole ratio of benzene to CO₂ is 2:12, or 1:6. Using this ratio, we calculate the moles of CO₂ produced:
Moles of CO₂ = 0.4125 moles * 6 = 2.475 moles
Now, we use the molar mass of CO₂ (44.01 g mol⁻¹) to find the mass:
Mass of CO₂ = 2.475 moles * 44.01 g mol⁻¹ = 108.92 g
Therefore, the mass of CO₂ formed when 9.25 liters of benzene is burned at STP is 108.92 g, rounded to two decimals.