Chapter 7, Problem 12A

Interpretation Introduction

Interpretation: The unbalanced chemical equation for the reaction of combination of hydrogen gas with oxygen gas of air to form water should be determined.

Concept Introduction: An unbalanced reaction is that chemical reaction in which the number of atoms of each element in the product side and on reactant side are not equal.

Answer to Problem 12A

The unbalanced chemical equation is:

  ${\text{H}}_{\text{2}}\left(\text{g}\right){\text{ + O}}_{\text{2}}\left(\text{g}\right)\to {\text{ H}}_{\text{2}}\text{O}\left(\text{g}\right)$

Explanation of Solution

The molecular formula for hydrogen gas is ${\text{H}}_{\text{2}}$ .

The molecular formula for oxygen gas is ${\text{O}}_{\text{2}}$ .

The molecular formula for water is ${\text{H}}_{\text{2}}\text{O}$ .

The physical state of the reactants and products are shown by writing the symbols after each reactant and product in the reaction. The symbol “l” represents liquid, “aq” represents aqueous, “s” represents solid, and “g” represents gas.

The reaction of combination of hydrogen gas with oxygen gas of air to form water is written as:

  ${\text{H}}_{\text{2}}\left(\text{g}\right){\text{ + O}}_{\text{2}}\left(\text{g}\right)\to {\text{ H}}_{\text{2}}\text{O}\left(\text{g}\right)$

This reaction is not balanced as:

The number of mol of $\text{O}$ on reactant side is 2 and on product side is 1.

Conclusion

The unbalanced chemical equation is:

  ${\text{H}}_{\text{2}}\left(\text{g}\right){\text{ + O}}_{\text{2}}\left(\text{g}\right)\to {\text{ H}}_{\text{2}}\text{O}\left(\text{g}\right)$