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Monday, 2 February 2015

Law Of Conservation Of Mass

law of conservation of mass


In 1748 formulated MW Lomonosov (1711-1765), the law of conservation of mass. The same law was AL Lavoisier (1743-1794), when he the reaction of metals with air (oxygen) investigated with the aid of the balance. The main merit of that research was the introduction of the scale in chemical works.

First chemical constitution

In a reaction, the mass of the substances concerned remains unchanged. The sum of the masses of the reaction products is thus equal to the sum of the masses of starting materials.

Mass of the starting materials = mass of the resulting materials


In 1756, Mikhail Lomonosov repeated this experiment Boyle and came to the conclusion that the phlogiston theory could not be true. Before Lomonosov opened the fed molten glass vessel, he placed a lighted candle in front of the opening. The candle flame was drawn at the moment of the opening in the vessel. Upon heating of lead in the sealed vessel was thus a part of the air "disappeared". The reaction product of the lead was now heavier than the lead before the experiment. Lomonosov wrote in his diary. "Today I conducted an experiment in hermetically sealed glass vessels, to see if the mass of a metal is larger under the mere action of heat The experiments of which I append a 13-page report, showed that the famous Robert Boyle was misled, because without access of air from outside the mass of burnt metal remained unchanged. ... It is the air particles that combine with the metals when heated, and this in turn limes ". The "limes" today would be described as metal oxides.