The two important laws of chemical combination are:
i) Law of constant proportion:
The law states that “in a chemical substance, the elements are always present in definite proportions by mass.
For example: In ammonia (NH3), nitrogen and hydrogen are always present in the ratio of 14:3 by mass, whatever the method
or source from which it is obtained.
In water, hydrogen and oxygen are always present in the ratio of 1:8 by mass, whatever the method or source from which water is obtained.
ii) Law of conservation of mass:
According to the law of conservation of mass states, atoms are neither created nor destroyed in a chemical reaction. This means that the total mass of the products formed in a chemical reaction must be equal to the mass of reactants consumed.
For example:
CaCO3 → CaO + CO2
100g 56g 44g
Sum of mass of reactants = Sum of masses of prodcuts
