When balancing a chemical reaction, you adjust the stoichiometric coefficients in front of each chemical formula. These coefficients represent the number of moles of each reactant and product involved in the reaction.

Here's what you don't change:

* Chemical formulas: You never change the subscripts within the chemical formulas themselves. This would alter the identity of the compound.

Example:

Unbalanced: H₂ + O₂ → H₂O

Balanced: 2H₂ + O₂ → 2H₂O

In this example, we added a coefficient of "2" in front of H₂ and H₂O to balance the number of hydrogen and oxygen atoms on both sides of the equation.

Why do we balance chemical reactions?

Balancing chemical reactions is crucial because it ensures that:

* The law of conservation of mass is obeyed: The total mass of the reactants must equal the total mass of the products.

* The correct mole ratios are represented: This allows you to accurately predict the amounts of reactants and products involved in a reaction.

* The reaction is stoichiometrically accurate: This means the reaction proceeds with the correct proportions of reactants and products.