calculating maximum mass

Question

Liquid hexane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water Suppose 6.0 g of hexane is mixed with 36.8 g of oxygen. Calculate the maximum mass of carbon dioxide that could be produced by the chemical reaction. Be sure your answer has the correct number of significant digits.

Answer 1

Hexane is C₆H₁₄ and this is a combustion reaction.

2C₆H₁₄ + 19O₂ ==> 12CO₂ + 14H₂O ... balanced equation

First, find which reactant is limiting:

For hexane: 6.0 g x 1 mol/86.18 g x 12 moles CO₂/2 moles hexane = 0.4177 moles CO₂ formed

For O₂: 36.8 g x 1 mole/32 g x 12 moles CO₂/19 moles O₂ = 0.7263 moles CO₂ formed

Thus, hexane (C₆H₁₄) is limiting and will determine the maximum mass of CO₂ produced

Maximum mass CO₂ = 0.4177 moles CO₂ x 44 g/mole = 18.38 g = 18 g CO₂ (to 2 sig. figs.)