Question

How to balance chemical equations?

Answer 1

Balancing chemical equations:

Balancing chemical equation refers to balancing the stoichiometric coefficients on the reactants and products side which is because the chemical equation must obey the law of conservation of mass.

By using the following steps we can balance the equation:

Step 1: Writing down the Unbalanced Chemical Equation.

Let us consider an unbalanced equation as; $\mathrm{Fe}+{\mathrm{O}}_2\to {\mathrm{Fe}}_2{\mathrm{O}}_3$

Step 2: Write down the number of atoms.

Write down the number of atoms of each element present on both reactants as well as product sides.

Atom	Reactant side	Product side
Fe	1	2
O	2	3

Step 3: Add Coefficients To Balance the Mass in a Chemical Equation.

The coefficients that are to be added must be a whole number and one coefficient added applies to all the atoms present in that one particular molecule.

For example: 2H₂O implies 4 hydrogen atoms and 2 oxygen atoms.

• Firstly, balance the single element atom and then move to Hydrogen and Oxygen.
• Hence, first balance Iron and then Oxygen by using the trial and error method.
• We can add 2 Iron on both sides won’t work as on the reactant side it will be 2 and on product 4, so we then have to move on to 3, and then 4.
• 4 Fe works, 2 Iron oxide molecule, making it 2 ${\mathrm{Fe}}_2{\mathrm{O}}_3$.

$\therefore \underset{\mathrm{Iron}}{4\mathrm{Fe}}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2}\to \underset{\mathrm{Ferric}\mathrm{oxide}}{2{\mathrm{Fe}}_2{\mathrm{O}}_3}$

• The same trial and error procedure is now followed to balance oxygen.
• 3O₂ then we have 6 oxygen atoms on the reactant side and also 6 oxygen atoms on the product side.
• Hence The balanced chemical equation is: $\underset{\mathrm{Iron}}{4\mathrm{Fe}}+\underset{\mathrm{Oxygen}}{3{\mathrm{O}}_2}\to \underset{\mathrm{Ferric}\mathrm{oxide}}{2{\mathrm{Fe}}_2{\mathrm{O}}_3}$.