Question

Consider the combustion reaction for octane (C8H18), which is a primary component of gasoline. 2C8H18+25O2⟶16CO2+18H2O How many moles of CO2 are emitted into the atmosphere when 18.1 g C8H18 is burned?

Answer 1

1.268 mol CO2

Step-by-step explanation:

1. Convert 18.1 g C8H18 to moles.

Divide 18.1 g by C8H18's molar mass. C8H18 has a molar mass of (8 x 12.0107) + (18 x 1.008) because there are 8 carbon atoms (which each have a molar mass of 12.0107 g/mol) and 18 hydrogen atoms (which each have a molar mass of 1.008 g/mol).

Molar mass of C8H18: (8 x 12.0107) + (18 x 1.008) = 114.23 g

18.1 g/114.23 g = 0.1585 mol

2. Use the balanced equation to find moles of CO2.

Multiply 0.1585 mol C8H18 by the ratio of moles from the balanced equation. For every 2 moles of C8H18, there are 16 moles of CO2. You can divide moles of C8H18 by 2, its coefficient, and multiply by 16, CO2's coefficient.

0.1585 x 16/2 = 1.268 mol CO2