Question

How can I balance decomposition reaction?

Answer 1

when a reactant breaks down into two or more products, it is known as decomposition reaction. They are both endothermic reactions and exothermic reactions. It is used for the extraction of metals from their ores, thermite welding, and manufacture of cement.

Complete answer:
Decomposition reaction takes place in our daily life just like digestion of food in our body. Food contains carbohydrates, fats, proteins which decompose into smaller units. A large amount of energy is released when the body works.
There are three types of decomposition reaction-
Thermal decomposition reaction- on heating, the substance breaks down into two or more smaller substances. For example- calcium carbonate decomposition
Electrolytic decomposition reaction- when an electric current is passed in an aqueous solution of a compound. It leads in an electrolytic decomposition reaction. For example-electrolysis of water.
Photo decomposition reaction- when a substance is put into sunlight, it breaks down into smaller units. For examples- hydrogen peroxide decomposition reaction.
We balance decomposition reaction just like a normal chemical reaction. put coefficients in front of every formula to maintain the same number of atoms in both the sides. Don’t change the formula by changing the subscripts.
Let us take an example of decomposition of magnesium oxide into magnesium and oxygen.
$MgO\left( s \right)\to Mg\left( s \right)+{{O}_{2}}\left( g \right)$
The number of oxygen atoms on both sides is not equal therefore we write a coefficient of $2$ in front of the $MgO$ . This will balance the oxygen atoms.
Now let us write the reaction-
$2MgO\left( s \right)\to Mg\left( s \right)+{{O}_{2}}\left( g \right)$
Now, we can see that the number of magnesium atoms is not equal on both the sides. Therefore. We will add a coefficient of $2$ in front of the magnesium atom.
Now let us write the final chemical reaction-
$2MgO\left( s \right)\to 2Mg\left( s \right)+{{O}_{2}}\left( g \right)$
Now, the chemical reaction is balanced. This is how we balance the decomposition reaction.

Note: Chemical reaction is defined as the process in which chemicals are reacted to form products. A compound undergoes change in composition depends upon the chemical properties of the elements. We should have complete knowledge about the balancing of a chemical reaction. The balanced chemical reaction, the product and the reactant have the same number of atoms present.