SEP Construct an Explanation A common mistake when balancing equations is t change the subscripts instead of the coefficients. For example, a person might t to balance the reaction H_(2)+O_(2)arrow H_(2)O by changing one subscript in the products: H_(2)+O_(2)arrow H_(2)O_(2) Explain how changing the subscript makes the equation incorrect.

Changing the subscript in a chemical equation changes the identity of the substance, which is not allowed when balancing equations. In the given example, changing the subscript in the product from H2O to H2O2 changes the identity of the product from water (H2O) to hydrogen peroxide (H2O2). This is not a correct way to balance the equation.<br /><br />When balancing a chemical equation, the goal is to ensure that the number of atoms of each element is the same on both sides of the equation. This is done by changing the coefficients, which are the numbers in front of the chemical formulas, not the subscripts.<br /><br />In the correct balanced equation, the number of atoms of each element is the same on both sides of the equation. For example, in the balanced equation:<br /><br />$2H_{2}+O_{2}\rightarrow 2H_{2}O$<br /><br />There are 4 hydrogen atoms and 2 oxygen atoms on both sides of the equation, so it is balanced.<br /><br />Changing the subscript in the product from H2O to H2O2 changes the identity of the product and makes the equation incorrect. The correct way to balance the equation is to change the coefficients, not the subscripts.