C8H18+O2=O2+H2O Stoichiometry

Question

C8H18+O2=O2+H2O

a. A liter of gasoline has a mass of about 702 g. What mass of carbon dioxide is produced when 2 liters of gasoline burns?

b. How many moles of water will be produced from 1 mole of octane?

c. How many moles of carbon dioxide can be produced from 54 g of oxygen?

d. How many grams of octane are needed to produce 6 moles of water?

e. How many molecules of carbon dioxide are produced from 2 moles of octane?

Answer 1

The first thing to do is to BALANCE the equation. Without a correctly balanced equation, you cannot move forward answering the question. (Note that CO₂ is produced, not O₂)

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

a. 2 L x 702 g / L x 1 mol C₈H₁₈ / 114 g x 16 mol CO₂ / 2 mol C₈H₁₈ x 44 g / mol = 4335 g CO₂

b. 1 mol C₈H₁₈ x 18 mol H₂O / mol C₈H₁₈ = 18 mols H₂O

c. 54 g O₂ x 1 mol O₂ / 32 g x 16 mol CO₂ / 25 mol O₂ = 1.08 mols CO₂

d. 6 mol H₂O x 2 mol C₈H₁₈ / 18 mol H₂O x 114 g C₈H₁₈ / mol = 76 g C₈H₁₈

e. 2 mol C₈H₁₈ x 16 mol CO₂ / 2 mol C₈H₁₈ x 6.02x10²³ molecules/mol = 9.6x10²⁴ molecules CO₂