Main article: Chemical lawChemical reactions are governed by certain laws, which have become fundamental concepts in chemistry. Some of them are:
Avogadro's law
Beer-Lambert law
Boyle's law (1662, relating pressure and volume)
Charles's law (1787, relating volume and temperature)
Fick's law of diffusion
Gay-Lussac's law (1809, relating pressure and temperature)
Le Chatelier's Principle
Henry's law
Hess's Law
Law of conservation of energy leads to the important concepts of equilibrium, thermodynamics, and kinetics.
Law of conservation of mass continues to be conserved in isolated systems, even in modern physics. However, special relativity shows that due to mass-energy equivalence, whenever non-material "energy" (heat, light, kinetic energy) is removed from a non-isolated system, some mass will be lost with it. High energy losses result in loss of weighable amounts of mass, an important topic in nuclear chemistry.
Law of definite composition, although in many systems (notably biomacromolecules and minerals) the ratios tend to require large numbers, and are frequently represented as a fraction.
Law of multiple proportions
Raoult's Law
Source: Wikipedia