Why is the following chemical equation not balanced? H_(2)+O_(2)arrow H_(2)O each side of the equation has a different number of oxygen atoms each side has the same mass each side of the equation has a different number of hydrogen atoms

The chemical equation $H_{2}+O_{2}\rightarrow H_{2}O$ is not balanced because each side of the equation has a different number of oxygen atoms. In a balanced chemical equation, the number of atoms of each element must be the same on both sides of the equation. In this case, there are 2 oxygen atoms on the left side (in $O_{2}$) and only 1 oxygen atom on the right side (in $H_{2}O$). Therefore, the equation is not balanced.