The complete question is: [tex]CH_{4}(g) + O_{2}(g) \rightarrow CO_{2}(g) + H_{2}O(g)[/tex] balance?
Answer: [tex]CH_{4}(g) + 2O_{2}(g) \rightarrow CO_{2}(g) + 2H_{2}O(g)[/tex] is a balanced equation.
Explanation:
A chemical equation which contains same number of atoms on both reactant and product side is called a balanced chemical equation.
For example, [tex]CH_{4}(g) + O_{2}(g) \rightarrow CO_{2}(g) + H_{2}O(g)[/tex]
Here, number of atoms on reactant side are as follows.
Number of atoms on product side are as follows.
To balance this equation multiply [tex]O_{2}[/tex] by 2 on reactant side and multiply [tex]H_{2}O[/tex] by 2 on product side. Hence, the equation can be re-written as follows.
[tex]CH_{4}(g) + 2O_{2} \rightleftharpoons CO_{2}(g) + 2H_{2}O(g)[/tex]
Here, number of atoms on reactant side are as follows.
Number of atoms on product side are as follows.
Since, there are same number of atoms on both reactant and product side. So, this equation is a balanced equation.
Thus, we can conclude that [tex]CH_{4}(g) + 2O_{2}(g) \rightarrow CO_{2}(g) + 2H_{2}O(g)[/tex] is a balanced equation.