Balance this equation. underline ( )CH_(4)+underline ( )O_(2)arrow underline ( )CO_(2)+underline ( )H_(2)O 0.2.0.2 2.1.2.1 1,2,1,2 1,2,1,1

To balance the chemical equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation.<br /><br />Given equation: $CH_{4} + O_{2} \rightarrow CO_{2} + H_{2}O$<br /><br />Step 1: Balance the carbon atoms.<br />There is 1 carbon atom on the left side and 1 carbon atom on the right side. So, the carbon atoms are already balanced.<br /><br />Step 2: Balance the hydrogen atoms.<br />There are 4 hydrogen atoms on the left side and 2 hydrogen atoms on the right side. To balance the hydrogen atoms, we need to multiply the number of $H_{2}O$ molecules by 2.<br /><br />$CH_{4} + O_{2} \rightarrow CO_{2} + 2H_{2}O$<br /><br />Step 3: Balance the oxygen atoms.<br />Now, we have 2 oxygen atoms on the left side and 4 oxygen atoms on the right side. To balance the oxygen atoms, we need to multiply the number of $O_{2}$ molecules by 2.<br /><br />$CH_{4} + 2O_{2} \rightarrow CO_{2} + 2H_{2}O$<br /><br />The balanced equation is: $CH_{4} + 2O_{2} \rightarrow CO_{2} + 2H_{2}O$<br /><br />Therefore, the correct answer is: $1, 2, 1, 2$.