Question

a)Translate the following chemical change in the form of a chemical equation.

b) Make it informative.

c) Balance it if required.

Nitrogen gas reacts with gaseous oxygen to produce gaseous nitrogen dioxide.

Answer 1

Any chemical change in the matter which involves transformation into one or more substances with entirely different properties is known as a chemical reaction.

Chemical reactions can be represented by chemical equations. The substances that take part in the chemical reaction are called reactants and the chemicals which are formed as a result of the reaction between reactants is known as product.

$\mathrm{X}+\mathrm{Y}\to \mathrm{P}$ in the given equation X and Y are reactants and P is the product.

Nitrogen gas reacts with gaseous oxygen to produce gaseous nitrogen dioxide.

In this reaction

reactant = Nitrogen (${\mathrm{N}}_2$), oxygen (${\mathrm{O}}_2$)

Product = Nitrogen dioxide (${\mathrm{NO}}_2$)

Chemical equation: ${\mathrm{N}}_2+{\mathrm{O}}_2\to {\mathrm{NO}}_2$

b) Informative chemical equation:

The chemical equation can be made more informative by adding the following properties:

• physical state of reactant and product
• Evolution of gas
• precipitate formed
• reaction conditions like temperature and pressure
• evolution or absorption of heat during the reaction.

$\underset{\mathrm{nitrogen}}{{\mathrm{N}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{nitrogen}\mathrm{dioxide}}{{\mathrm{NO}}_2\left(\mathrm{g}\right)}$

c) Balanced equation: the chemical equation in which the number of atoms of each element on the reactant side as well as the product side is equal are known as a balanced equation.

Balancing the following chemical equation:

$\underset{\mathrm{nitrogen}}{{\mathrm{N}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{nitrogen}\mathrm{dioxide}}{{\mathrm{NO}}_2\left(\mathrm{g}\right)}$

Steps to balance the chemical equation:

• Count the number of atoms of each element on either side. Now first balance the compound with the maximum number of atoms

A number of atoms of each element on the reactant side:

$\mathrm{N}=2,\mathrm{O}=2$

A number of atoms of each element on the product side:

$\mathrm{N}=1,\mathrm{O}=2$

As the number of nitrogen atoms are not equal on both the reactant and product sides so we will first balance nitrogen by multiplying nitrogen dioxide on the product side by 2. Equation becomes

$\underset{\mathrm{nitrogen}}{{\mathrm{N}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{nitrogen}\mathrm{dioxide}}{2{\mathrm{NO}}_2\left(\mathrm{g}\right)}$

now balance the oxygen by multiplying oxygen by 2 on the reactant side by 2.

$\underset{\mathrm{nitrogen}}{{\mathrm{N}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{oxygen}}{2{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{nitrogen}\mathrm{dioxide}}{2{\mathrm{NO}}_2\left(\mathrm{g}\right)}$

Now no. of oxygen and nitrogen atoms becomes equal on both the reactant and product side i.e. $\mathrm{N}=2,\mathrm{O}=4$

Thus the $\underset{\mathrm{nitrogen}}{{\mathrm{N}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{oxygen}}{2{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{nitrogen}\mathrm{dioxide}}{2{\mathrm{NO}}_2\left(\mathrm{g}\right)}$equation is balanced.