Conservation of mass

[1] The law implies that mass can neither be created nor destroyed, although it may be rearranged in space, or the entities associated with it may be changed in form.

The concept of mass conservation is widely used in many fields such as chemistry, mechanics, and fluid dynamics.

The formulation of this law was of crucial importance in the progress from alchemy to the modern natural science of chemistry.

In reality, the conservation of mass only holds approximately and is considered part of a series of assumptions in classical mechanics.

For very energetic systems the conservation of mass only is shown not to hold, as is the case in nuclear reactions and particle-antiparticle annihilation in particle physics.

For systems that include large gravitational fields, general relativity has to be taken into account; thus mass–energy conservation becomes a more complex concept, subject to different definitions, and neither mass nor energy is as strictly and simply conserved as is the case in special relativity.

The law of conservation of mass can only be formulated in classical mechanics, in which the energy scales associated with an isolated system are much smaller than

In chemistry, the calculation of the amount of reactant and products in a chemical reaction, or stoichiometry, is founded on the principle of conservation of mass.

The Jain text Tattvarthasutra (2nd century CE) states that a substance is permanent, but its modes are characterised by creation and destruction.

An explicit statement of this, along with the further principle that nothing can pass away into nothing, is found in Empedocles (c. 4th century BCE): "For it is impossible for anything to come to be from what is not, and it cannot be brought about or heard of that what is should be utterly destroyed.

"[8] A further principle of conservation was stated by Epicurus around the 3rd century BCE, who wrote in describing the nature of the Universe that "the totality of things was always such as it is now, and always will be".

By the 18th century the principle of conservation of mass during chemical reactions was widely used and was an important assumption during experiments, even before a definition was widely established,[10] though an expression of the law can be dated back to Hero of Alexandria’s time,[11] as can be seen in the works of Joseph Black, Henry Cavendish, and Jean Rey.

He may have demonstrated it by experiments and certainly had discussed the principle in 1748 in correspondence with Leonhard Euler,[13] though his claim on the subject is sometimes challenged.

[14][15] According to the Soviet physicist Yakov Dorfman:The universal law was formulated by Lomonosov on the basis of general philosophical materialistic considerations, it was never questioned or tested by him, but on the contrary, served him as a solid starting position in all research throughout his life.

[16] A more refined series of experiments were later carried out by Antoine Lavoisier who expressed his conclusion in 1773 and popularized the principle of conservation of mass.

[17] The demonstrations of the principle disproved the then popular phlogiston theory that said that mass could be gained or lost in combustion and heat processes.

The conservation of mass was obscure for millennia because of the buoyancy effect of the Earth's atmosphere on the weight of gases.

Once understood, the conservation of mass was of great importance in progressing from alchemy to modern chemistry.

Following the pioneering work of Lavoisier, the exhaustive experiments of Jean Stas supported the consistency of this law in chemical reactions,[18] even though they were carried out with other intentions.

[21] The difference in the accuracy aimed at and attained by Lavoisier on the one hand, and by Edward W. Morley and Stas on the other, is enormous.

In one of the Annus Mirabilis papers of Albert Einstein in 1905, he suggested an equivalence between mass and energy.

However, as Max Planck pointed out, a change in mass as a result of extraction or addition of chemical energy, as predicted by Einstein's theory, is so small that it could not be measured with the available instruments and could not be presented as a test of special relativity.

The Combustion reaction of methane . Where 4 atoms of hydrogen, 4 atoms of oxygen, and 1 of carbon are present before and after the reaction. The total mass after the reaction is the same as before the reaction.
Russian scientist Mikhail Lomonosov formulated the law of mass conservation in 1756 and came to the conclusion that the phlogiston theory is incorrect. [ 3 ] [ 4 ] [ 5 ]
Antoine Lavoisier 's discovery of the law of conservation of mass led to many new findings in the 19th century. Joseph Proust 's law of definite proportions and John Dalton 's atomic theory branched from the discoveries of Antoine Lavoisier. Lavoisier's quantitative experiments revealed that combustion involved oxygen rather than what was previously thought to be phlogiston .