Question

Answer the question related to the chemical equation given below

$\mathrm{Mg}+{\mathrm{O}}_2\to \mathrm{MgO}$

1. Identify the reactants and products.
2. Balance the above and also make it more informative.
3. What is the valency of two elements involved in the reaction.

Answer 1

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.

In the given reaction $\mathrm{Mg}+{\mathrm{O}}_2\to \mathrm{MgO}$ magnesium$\mathrm{Mg}$ and oxygen${\mathrm{O}}_2$ are reactants and magnesium oxide $\mathrm{MgO}$ is the product.

2. 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 is known as a balanced equation.

Balancing the following chemical equation:

$\mathrm{Mg}+{\mathrm{O}}_2\to \mathrm{MgO}$

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:

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

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

$\mathrm{Mg}=1,\mathrm{O}=1$

• As the number of oxygen is not equal on both the reactant and product sides so we will first multiply magnesium oxide ($\mathrm{MgO}$) by 2 on the product side. The reaction becomes:

$\mathrm{Mg}+{\mathrm{O}}_2\to 2\mathrm{MgO}$

• Now balance the magnesium ($\mathrm{Mg}$) on the reactant side by multiplying it by 2.

$\underset{\mathrm{Magnesium}}{2\mathrm{Mg}\left(\mathrm{s}\right)}+\underset{\mathrm{oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{magnesium}\mathrm{oxide}}{2\mathrm{MgO}\left(\mathrm{s}\right)}$

• Now the number of magnesium and oxygen atoms are balanced on both the reactant and product side i.e. $\mathrm{Mg}=2,\mathrm{O}=2$. Thus the reaction is balanced.

3. Valency is the combining tendency of an element or radical. It is the number of electrons lose or gain by an atom of an element in order to complete its octet and attain stability.

Valency of $\mathrm{Mg}=2$ and oxygen is also $\mathrm{O}=2$