* Subscripts represent the chemical formula: Subscripts in a chemical formula (like H₂O) indicate the number of atoms of each element within a molecule. Changing them alters the chemical identity of the substance. For example, H₂O is water, but H₂O₂ is hydrogen peroxide – completely different compounds.
* Balancing equations involves coefficients: To balance a chemical equation, you adjust the *coefficients* in front of each compound, not the subscripts. Coefficients tell you how many molecules of each substance are involved in the reaction.
Let's illustrate with an example:
Unbalanced Equation:
H₂ + O₂ → H₂O
Balanced Equation:
2H₂ + O₂ → 2H₂O
Explanation:
* Original: The equation is unbalanced because there are 2 oxygen atoms on the left side and only one on the right.
* Balancing: We add a coefficient of '2' in front of H₂O to balance the oxygen atoms. This also requires a coefficient of '2' in front of H₂ to balance the hydrogen atoms.
Key Takeaway: Changing subscripts would change the compounds themselves, making the equation incorrect. Balancing involves adjusting the coefficients to ensure the same number of atoms of each element on both sides of the equation.
