Chapter 18, Problem 113E

Interpretation Introduction

Interpretation: The minimum volume of oxygen gas needed for the complete combustion of given amount of octane is to be calculated at STP.

Concept Introduction: In combustion reaction, hydrocarbons are burnt in the presence of oxygen to give carbon dioxide and water as the products.

To determine the volume of oxygen gas needed for the complete combustion of given amount of octane, follow the following solution map:

$\boxed{\begin{array}{l}\text{given}\\ \text{mass}\text{of}\text{octane}\end{array}}\to \boxed{\text{moles of octane}}\underset{\begin{array}{l}\text{By}\text{using}\\ \text{conversion}\\ \text{factor}\end{array}}{\to }\boxed{\text{moles}\text{of}{\text{O}}_2}\to \boxed{\text{Volume}\text{of}{\text{O}}_2}$

The mass of octane is converted into their corresponding moles by the use of their corresponding molar masses. The conversion factor used to convert the moles of octane into the moles of $O_2$ is basically the stoichiometric relationship between moles of octane and moles of $O_2$. The conversion factor is obtained from the balanced chemical equation. The moles of $O_2$ is converted into their corresponding volume by the use of molar volume of gas at STP as a conversion factor.