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 24.1 g of C8H18 is burned?

Answer 1

Octane combustion reaction is:

   2C₈H₁₈ + 25O₂ --> 16CO₂ + 18H₂O

In the reaction 2 moles C₈H₁₈ burns with O₂ to produce 16 moles of CO₂.

We have 24.1 g of C₈H₁₈, so we should calculate the no. moles we are burning.

No. moles of C₈H₁₈ = (mass of C₈H₁₈)/(mol. weight of C₈H₁₈) = 24.1 g/114.23 g/mol = 0.211 moles

Therefore, 2 moles C₈H₁₈ produces 16 moles of CO₂

and we have 0.211 moles, so how many moles of CO₂ produces =?

No. moles of CO₂ produced = 0.211 moles x 16 moles/ 2 moles = 1.69 moles

Therefore, no. of moles of CO₂ emitted into the atmosphere is = 1.69 moles