Question

Magnesium ribbon is burnt in the presence of oxygen gas to produce white solid magnesium oxide.

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

(b) Make it informative

(c) Balance it if required

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.

(a) Magnesium ribbon is burnt in the presence of oxygen gas to produce white solid magnesium oxide.

In this reaction the magnesium ribbon ($\mathrm{Mg}$) and oxygen (${\mathrm{O}}_2$) gas are reactants and the solid white magnesium oxide ($\mathrm{MgO}$) is the product. So it can be represented by the following chemical equation:

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

(b) the reaction can be made more informative by adding the physical state, name of the reactant and products as well as temperature and pressure, heat evolution or absorption, etc.

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

(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 is known as a balanced equation.

Balancing the following chemical equation:

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

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:

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

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 andproduct sides so we will first multiply $\mathrm{MgO}$ (magnesium oxide) by 2 on the product side. The reaction becomes:

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

• Now magnesium isbalanced by multiplying magnesium on the reactant side by 2.

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

Thus the number of atoms of magnesium and oxygen is equal on both the reactant and product side which is $\mathrm{Mg}=2,\mathrm{O}=2$

Hence, the $\underset{\mathrm{magnesium}}{2\mathrm{Mg}\left(\mathrm{s}\right)}+\underset{\mathrm{oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{magnesium}\mathrm{oxide}}{2\mathrm{MgO}\left(\mathrm{s}\right)}$is a balanced equation.