Question

Define the law of conservation of mass. How is it applicable to chemical reaction.

Answer 1

The law of conservation of mass states that “ the mass of the system can neither be created nor be destroyed it only transforms from one form to another”

The law was given by a French Chemist named Antoine Lavoisier (1789).

This law states that in a chemical reaction, the mass of products equals to the mass of reactants.

Application of Law of mass action on chemical reaction

For example, in the following chemical equation

$\underset{\mathrm{hydrogen}}{2{\mathrm{H}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{water}}{2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

the mass of the reactant is the atomic mass of ($4\mathrm{H}+2\mathrm{O}$)= (4+32)= 36

the mass of the product is a molecular mass of $2{\mathrm{H}}_2\mathrm{O}$ =36

So the mass of the reactant is equal to the mass of the product.