Molecular and ionic equation balancing, limiting reagent and theoretical yield
Tip: Use plain numbers for subscripts (H2O) and + or - signs at the end for ions (Fe+3, SO4-2)
Where ni is the available moles and ai is the stoichiometric coefficient.
In every chemical reaction, the total mass of reactants equals the total mass of products. Atoms are neither created nor destroyed — they are simply rearranged. Stoichiometric balancing ensures each element has the same number of atoms on both sides of the equation.
When defined amounts of reactants are mixed, the limiting reagent is the one that is completely consumed first, determining the maximum amount of product that can be formed. The remaining reactants are said to be in excess.
In oxidation-reduction reactions, besides conserving mass, the electric charge must also be conserved. The electrons lost by the oxidized species must equal the electrons gained by the reduced species.
Theoretical yield: the maximum amount of product calculated from the limiting reagent, assuming a complete reaction (100% yield).