Final answer:
In balancing chemical equations, it is essential to balance both the number of atoms and charges, as reactions involve the transfer or sharing of electrons.
Step-by-step explanation:
When dealing with chemical reactions and balancing chemical equations, it is crucial not only to balance the number of atoms but also to ensure that the charges are balanced.
This is because each reaction involves the transfer or sharing of electrons, and charge conservation is as essential as the conservation of matter. When iron forms ions, it can lose a different number of electrons to become either Fe²⁺ or Fe³⁺.
In the context of the question, balancing equations by adding 5's to the iron ions means balancing the number of charges on both sides of the equation.
For example, the iron half-reaction may show 2+ on the reactants side with Fe²⁺ and 3+ on the products side with Fe³⁺. To balance the charges, electrons are added or coefficients are adjusted until the total charge on both sides is equal, ensuring that charge conservation is adhered to just like the conservation of matter.
To understand why we need to include the 5's when balancing charges from an electron point of view, we need to consider that different ions of the same element can have different charges. In the case of iron, it can form two cations, Fe²+ and Fe³+, each with a different number of electrons.
When balancing charges, we need to ensure that the total positive charge on one side of the equation is equal to the total negative charge on the other side. By including the 5's, we are accounting for the different charges of the iron ions and ensuring charge balance in the reaction.