Question

How do you write a chemical equation to represent “Gaseous ammonia reacts with gaseous oxygen to form gaseous nitrogen monoxide and gaseous water”?

Answer 1

Hint: There are two reactants and two products in the reaction given in the question. The elements in ammonia are nitrogen and the elements in the nitrogen monoxide are nitrogen and oxygen.

Complete answer:
> “Gaseous ammonia reacts with gaseous oxygen to form gaseous nitrogen monoxide and gaseous water”, this statement contains two reactants and two products. The reactants are ammonia and oxygen, and the products are nitrogen monoxide and water.
> The compound ammonia has two elements i.e., nitrogen and hydrogen, so its formula will be $N{{H}_{3}}$.
> The compound oxygen has only one element i.e., oxygen and there are two oxygen atoms, so its formula will be ${{O}_{2}}$.
> The compound nitrogen monoxide has two elements i.e., nitrogen and oxygen, so its formula will be $NO$.
> The compound water has two elements i.e., oxygen and hydrogen, so its formula will be ${{H}_{2}}O$.
So, by placing all the compounds as the reaction, we can write the equation as:
$N{{H}_{3}}+{{O}_{2}}\to NO+{{H}_{2}}O$
> In the statement all the compounds are in a gaseous state so we have to write (g) with every compound in the equation. Therefore, the equation will be:
$N{{H}_{3}}(g)+{{O}_{2}}(g)\to NO(g)+{{H}_{2}}O(g)$
> Since this reaction is not balanced, we have to balance the equation. The balanced equation will be:
$4N{{H}_{3}}(g)+5{{O}_{2}}(g)\to 4NO(g)+6{{H}_{2}}O(g)$

Note: For balancing, the hydrogen and oxygen are balanced at the last, first we have to balance all the elements in the reaction other than hydrogen and oxygen. You can also add a water molecule to balance both hydrogen and oxygen at the same time.