Question

Q.18. Explain the law of conservation of mass, the law of definite proportion, and the law of multiple proportions.

Short answer

Answer

The law of conservation of mass discusses constant mass during a chemical change.

The law of definite proportions explains the fixed ratio of mass mixing of each element during the formation of a compound.

The law of multiple proportions talks about the multiple ratios of mixing an element with a fixed amount of other elements during the formation of its compounds.

Step-by-step solution

Step-by-Step SolutionStep 1: Law of conservation of mass with example

A French chemist named Antoine Lavoisier states that “Mass is neither created nor be destroyed. The mass before chemical reaction should be equal to the after chemical reaction”. For example, take that there are two reactants, A and B, to form C and D. Assume “a” g of A reacting with “b” g of B gives “c” g of C and “d” g of D. Take chemical reaction as,

A + B$\underset{}{\to }$C + D

$Thetotalmassofreac\tan ts=Totalmassofproducts$

a + b = c + d

Law of definite proportions with example

For example, whatever may be the source of CO₂ gas, either from respiration or by combustion of fossil fuels, the combining ratio of carbon and oxygen to form carbon dioxide is always fixed. It is described by the law of definite proportions.

Law of multiple proportions with example

For example, carbon and oxygen combine and form carbon monoxide and carbon dioxide. The ratio of oxygen that combines with carbon is in the ratio of 1:2 in both the compounds. This is the law of multiple proportions.