Question

Here is the combustion reaction for octane (c8h18), which is a primary component of gasoline. how many moles of co2 are emitted into the atmosphere when 15.1 g of c8h18 is burned?

Answer 1

Combustion reaction for octane is as follows.
2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O

Moles (mol) = mass (g) / molar mass (g/mol)

mass of octane = 15.1 g
molar mass of octane = 114.23 g/mol
Hence, moles of octane = 15. 1 g / 114.23 g/mol
                                       = 0.132 mol

The stoichiometric ratio between C₈H₁₈ and CO₂ is 1 : 8.
Hence,
    moles of CO₂ produced = moles of octane burnt x 8
                                          = 0.132 mol x 8
                                          = 1.056 mol

Hence, 15.1 g of octane produce 1.056 moles of CO₂.