Question

Explain the law of conservation of mass with the help of an example.

Answer 1

• The Law of Conservation of Mass was given by Antoine Laurent Lavoisier in 1789.
• It states that mass can neither be created nor destroyed during a chemical reaction but can be transformed from one form to another.
• The mass of the reactants and the products remains the same during a chemical reaction.

For example: When 100g of mercuric oxide is heated, 92.6 g of mercury and 7.4 g of oxygen are formed.

$\mathrm{Hg}\to \mathrm{Hg}+{\mathrm{O}}_2$
In this case mass of reactant $\mathrm{Hg}$ = $100g$
Mass of products = Mass of $\mathrm{Hg}$+ Mass of ${\mathrm{O}}_2$= $92.6+7.4=100g$
Therefore, the mass of the product = Mass of reactants
This verifies the law of conservation of mass.