How to balance chemical equations

Balancing chemical equation refers to balancing the stoichiometric coefficients on the reactants and products side. This must be done as the chemical equation obeys the law of conservation of mass and momentum.

Steps to balance chemical equation

Following are the easy steps to balance the equation:

Step 1: Write the Unbalanced Chemical Equation

Let us consider an unbalanced equation

Fe + O2 → Fe2O3

Step 2: Write Down Number of Atoms

Write down the number of atoms of each element present on both reactant as well as product side

Atom Reactant side Product side
Fe 1 2
O 2 3

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

Note that 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: 2 H2O implies 4 hydrogen atoms and 2 oxygen atoms.

First try to balance the single element o atom and then move n to hydrogen and oxygen.

So here we will first balance Iron and then oxygen

Go by trial and error method. Adding 2 iron-on both sides won’t work as in the reactant side it will be 2 and on product 4. Then move on to 3, and then 4.

4 Fe works, 2 iron oxide molecule, making it 2 Fe2O3

4 Fe + O2 → 2 Fe2O3

The same trial and error procedure is now followed to balance oxygen

3 O2 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:

4 Fe + 3 O2 → 2 Fe2O3

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