Chapter EH, Problem 9R

Solution

Interpretation: The balanced equation for the reaction between lithium and water needs to be determined.

Concept Introduction: A chemical reaction is said to be balanced if there are an equal number of the same atoms on both sides of the reaction arrow.

  $\text{Li}\left(s\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)\to \text{LiOH}\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

The reaction between lithium and water gives lithium hydroxide and hydrogen gas. The reaction can be represented as follows:

  $\text{Li}\left(s\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)\to \text{LiOH}\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

The above equation can be balanced by giving coefficient 2 to $\text{Li}\left(s\right)$ , $+{\text{H}}_{\text{2}}\text{O}\left(l\right)$ , and $\text{LiOH}\left(aq\right)$ .

  $\text{2Li}\left(s\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)\to 2\text{LiOH}\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

Thus, the balanced chemical equation is represented as follows:

  $\text{2Li}\left(s\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)\to 2\text{LiOH}\left(aq\right)+{\text{H}}_{\text{2}}\left(g\right)$

The balanced chemical equation has an equal number of atoms of the same elements on both sides of the reaction arrow.