Chapter 7.2, Problem 2RQ

Interpretation Introduction

Interpretation:

Several pieces of information must be listed which can determine a chemical reaction just by reading a chemical equation.

Concept Introduction:

A balanced chemical equation is the representation of the chemical reaction showing all the participants quantitatively.

Answer to Problem 2RQ

Formulae of all the reactants and products along with their physical states are obtained. Molar ratios are obtained in which all the reactants are reacted to give products. The number of each atom present in a compound is obtained from the subscripts.

Explanation of Solution

A chemical reaction is shown below.

  ${\text{CH}}_{\text{4}}{\text{(g)+2O}}_{\text{2}}\text{(g)}\to {\text{CO}}_{\text{2}}{\text{(g)+2H}}_{\text{2}}\text{O(g)}\text{.}$

Here it is clear that 1 mol CH₄ needs 2 moles of oxygen for complete combustion. 1 mol CO₂ and 2 moles water (steam) are produced. All the reactants and products are gaseous in this case.

In CH₄ there are 4 H atoms and 1 C atom per molecule. Similarly, there are 2 O atoms and 1 C atom per molecule of CO₂. There are 2 H atom and 1 O atom per molecule of H₂O. There are 2 O atoms per molecule of O₂.