Chapter 7, Problem 4STP

Interpretation Introduction

Interpretation: The coefficient for ${\text{O}}_{\text{2}}$ in the following reaction needs to be determined when the reaction is balanced:

  ${\text{C}}_{\text{4}}{\text{H}}_{\text{10}}{\text{(l) + O}}_{\text{2}}\text{(g) }\to {\text{CO}}_{\text{2}}\text{(g})+{\text{H}}_{\text{2}}\text{O(g)}$

Concept Introduction: The reactions for which the number of atoms of each element in the reactant and in the product, side are equal, such reactions are said to be a balanced chemical equation.

Answer to Problem 4STP

The correct option is (d): $\text{13}$ .

Explanation of Solution

The given reaction is:

  ${\text{C}}_{\text{4}}{\text{H}}_{\text{10}}{\text{(l) + O}}_{\text{2}}\text{(g) }\to {\text{CO}}_{\text{2}}\text{(g})+{\text{H}}_{\text{2}}\text{O(g)}$

The reaction is not balanced as the number of C, H and O in the reactant side is 4, 10 and 2 respectively and on the product’s side is 1, 2 and 3 respectively. So, in order to balance the reaction, coefficient 2 and 13 is written before ${\text{C}}_{\text{4}}{\text{H}}_{\text{10}}$ and ${\text{O}}_{\text{2}}$ on the reactant side and coefficient 8 and 10 is written before ${\text{CO}}_{\text{2}}$ and ${\text{H}}_{\text{2}}\text{O}$ on the product side. So, the balanced chemical reaction is:

  ${\text{2C}}_{\text{4}}{\text{H}}_{\text{10}}{\text{(l) + 13O}}_{\text{2}}\text{(g) }\to 8{\text{CO}}_{\text{2}}\text{(g})+10{\text{H}}_{\text{2}}\text{O(g)}$

Hence, the coefficient for ${\text{O}}_{\text{2}}$ in the balanced reaction is $\text{13}$ .