Hydrogen gas combines with Nitrogen to form ammonia. Translate the following into a chemical equation and balance the equation.

Hint: Write the chemical equation by mentioning the states in which the reactants and the products exist. The chemical species that are combining are written on the reactant side and the one being formed is written on the product side .

Complete answer:
Chemical reactions can be written on the basis of certain laws of chemical combination. One of these laws is the Law of conservation of mass. According to this law the total matter in a reaction remains conserved i.e. it is not possible to create or destroy the mass of atoms in a reaction.
If the mass remains conserved before and after a reaction takes place, then the number of atoms of each element participating in a reaction should also remain the same. Thus, the total number of atoms of each element present on the reactant side must be the same as that of the product side.
To write the chemical equation of the reaction between hydrogen and nitrogen, we must know that both these elements exist as diatomic gases in nature. The product formed is ammonia which is also released as a gas. The states of reactants and products must be mentioned in brackets along with their chemical symbol. The reactants and products are separated by an arrow. The equation can be written as follows:
\[{N_2}(g) + {H_2}(g) \to N{H_3}(g)\]
To balance the above equation, the number of atoms should be made equal on each side.
The reactant side contains two atoms of nitrogen, hence two molecules of ammonia should be produced. Multiply ammonia with two.
If two molecules of ammonia are being produced, then six hydrogen atoms should be consumed, multiple hydrogen molecules with three.
On doing these steps we observe that the number of atoms of both nitrogen and hydrogen are the same on the reactant as well as the product side. Hence, the balanced chemical equation is:
\[{N_2}(g) + 3{H_2}(g) \to 2N{H_3}(g)\]

Note:
Though the law of conservation of mass suggests that the atoms on both sides should remain the same, it does not mean that the atoms cannot change their state or form new bonds. It simply means that no new element can be formed or destroyed in a reaction, but the existing atoms are free to change their forms.