By studying the results of quantitative measurements of many reactions, scientists made certain generalizations.These generalizations are known as laws of chemical combinations.

A. Law of Conservation of Mass :It was proposed by Lavoiser and vertified by Landlot.

Matter can neither be created nor destroyed. (or)

In a chemical reaction the total mass of the reactants is equal to the total mass of the products.

B. Law of Definite Proportions :It was porposed by Proust and verified by Stass and Richards.

A chemical compound contains the same elements in a fixed ratio by weight.

C. Law of Multiple proportions :It was porposed by Dalton and verified by Berzelius.

When two elements combine to form two or more compounds, the different weights of one of the elements combining with the constant weight of the other bear a simple numerical ratio to one another.

D. Law of Reciprocal Proportions :It was proposed by Ritcher.

The ratio between the weights of two elements A and B which combine with the fixed weight of the third element C, will be same or simple multiples of the ratio in which the elements A and B combine together.

e. Law of Combining volumes :It was proposed by Gay – Lussac.

Volumes of reacting gases and product gases if any beat a simple numerical ratio to one another.