Wha is laws of chemical combination

The combination of elements to form compounds is governed by the following five basic laws. These laws are known as the laws of chemical combination.

Law of Conservation of Mass: It states that matter can neither be created nor destroyed.

Law of Definite Proportions (by mass): A given compound always contains exactly the same proportion of constituent elements by mass.

Law of Multiple Proportions: If two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element, are in the ratio of small whole numbers.

Gay Lussac’s Law of Gaseous Volumes: When gases combine or are produced in a chemical reaction, they do so in a simple ratio by volume (provided all gases are at same temperature and pressure). This is the law of
definite proportions by volume.

Avogadro's Law: Equal volumes of gases at the same temperature and pressure (STP) contain the same number of molecules.