Question

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

2C8 H18 + 25O₂…..16CO2+18H2O

How many moles of CO₂ are emitted into the atmosphere when 16.6 g C8H18 is burned?
CO₂ emitted:

Answer 1

1.16 moles CO₂

Step-by-step explanation:

To find the moles of CO₂, you need to (1) convert grams C₈H₁₈ to moles (via the molar mass) and then (2) convert moles C₈H₁₈ to moles CO₂ (via the mole-to-mole ratio from equation coefficients). It is important that the conversions/ratios are arranged in a way that allows for the cancellation of units. The final answer should have 3 significant figures like the given value.

Molar Mass (C₈H₁₈): 8(12.011 g/mol) + 18(1.008 g/mol)

Molar Mass (C₈H₁₈): 114.232 g/mol

2 C₈H₁₈ + 25 O₂ -----> 16 CO₂ + 18 H₂O
^ ^

16.6 g C₈H₁₈ 1 mole 16 moles CO₂
-------------------- x ----------------- x ------------------------- = 1.16 moles CO₂
114.232 g 2 moles C₈H₁₈