1. Law of conservation of mass
During any physical or chemical change, the total mass of the products is equal to the total mass of reactants.
2. Law of constant proportions
A pure chemical compound always contains same elements combined together in the same definite proportion by weight.
3. Law of multiple proportions
When two elements combine to form two or more than two compounds, the weights of one of the elements which combine with a fixed weight of the other, bear a simple whole number ratio.
4. Law of reciprocal proportions
When two different elements combine separately with the same weight of a third element, the ratio in which they do so will be the same or some simple multiple of the ratio in which they combine with each other.
5. Gay Lussac’s law of combing volumes
Under similar conditions of temperature and pressure, whenever gases react together, the volumes of the reacting gases as well as products (if gases) bear a simple whole number ratio.