Here's why:
* Subscripts represent the number of atoms of each element within a molecule. Changing a subscript would change the chemical composition of the molecule itself. For example, H₂O (water) is different from H₂O₂ (hydrogen peroxide).
* Balancing equations is about conserving mass. We use coefficients (numbers in front of the molecules) to adjust the number of molecules involved in the reaction, ensuring that the same number of atoms of each element are present on both sides of the equation.
Think of it like a recipe:
* The chemical formula is like the ingredient list (e.g., 2 eggs, 1 cup flour).
* You can change the number of times you make the recipe (coefficients), but you can't change the ingredients themselves (subscripts).
