Limiting reactants

Question

Liquid hexane (CH₃(CH₂)₄CH₃) will react with gaseous oxygen (O₂) to produce gaseous carbon dioxide (CO₂) and gaseous water (H₂O). Suppose 7.76 g of hexane is mixed with 16. g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to 2 significant digits.

Answer 1

Write the balanced equation for the reaction:

2C₆H₁₄(l) + 19O₂(g) ===> 12CO₂(g) + 14H₂O(g) ... balanced equation for combustion or hexane

Next, find the limiting reactant:

For C₆H₁₄: 7.76 g C₆H₁₄ x 1 mol C₆H₁₄ / 86.2 g x 14 mol H₂O / 2 mol C₆H₁₄ x 18 g H₂O/mol = 11.3 g H₂O

For O₂: 16. g O₂ x 1 mol O₂ / 32 g x 14 mol H₂O / 19 mol O₂ x 18 g H₂O/mol = 6.6 g H₂O

Since O₂ is limiting, the maximum amount of H₂O than can be produced = 6.6 g H₂O