Consider the combustion reaction for octane (C8H18) , which is a primary component of gasoline.

Question

How many moles of  are emitted into the atmosphere when  is burned?

Answer 1

Write a correctly balanced equation for the complete combustion of octane:

2C₈H₁₈ + 25O₂ ==> 16CO₂ + 18H₂O ... balanced equation

Determine how many moles of C8H18 are combusted:

19.6 g C₈H₁₈ x 1 mol/114.23 g = 0.1716 moles octane were combusted

Determine how many moles of CO₂ are generated from burning 0.1716 moles octane:

0.1716 moles octane x 16 moles CO₂/2 moles octane = 1.3728 moles CO₂ generated

Finally, convert moles CO₂ to grams of CO₂:

1.3728 moles CO₂ x 44 g/mol = 60.4 g CO₂ (to 3 significant figurers)