* Subscripts represent the number of atoms of each element in a molecule. Changing a subscript alters the identity of the molecule itself. For example, changing H₂O (water) to H₂O₂ would create hydrogen peroxide, a completely different substance with different properties.
* Balancing chemical equations is about conserving mass. You need the same number of each type of atom on both sides of the equation to reflect the law of conservation of mass.
How to Balance Chemical Equations:
You use coefficients in front of the chemical formulas to balance the equation. Coefficients represent the number of molecules or moles of each reactant and product involved.
Example:
The unbalanced equation for the reaction of hydrogen and oxygen to form water is:
H₂ + O₂ → H₂O
To balance this equation:
1. Count atoms: There are 2 hydrogen atoms and 2 oxygen atoms on the left side, but only 2 hydrogen atoms and 1 oxygen atom on the right.
2. Adjust coefficients: We need 2 oxygen atoms on the right, so add a coefficient of 2 in front of H₂O.
3. Recount atoms: Now we have 4 hydrogen atoms on the right, so we need to add a coefficient of 2 in front of H₂ on the left.
The balanced equation is:
2H₂ + O₂ → 2H₂O
