It is thought that there are certain assumptions in classical mechanics that define mass conservation. Later, the law of conservation of mass was modified using quantum mechanics and special relativity according to which energy and mass are a conserved quantity. In 1789, Antoine Laurent Lavoisier discovered the law of conservation of mass. Another principle of preservation was established by Epicurus around the 3rd century BC, who, describing the nature of the universe, wrote that “the totality of things has always been as it is now and always will be”. [7] The concept of mass conservation is widely used in many fields such as chemistry, mechanics and fluid dynamics. Historically, mass conservation in chemical reactions was independently proven by Mikhail Lomonosov and later rediscovered by Antoine Lavoisier in the late 18th century. The formulation of this law was crucial for the transition from alchemy to the modern science of chemistry. The change in mass of certain types of open systems, in which atoms or massive particles are not allowed to escape, but other types of energy (such as light or heat) are allowed to enter, escape or fuse, went unnoticed in the 19th century, because the change in mass associated with the addition or loss of small amounts of thermal or radiant energy in chemical reactions is very small. (Theoretically, the mass would not change at all for experiments in isolated systems where heat and work were not allowed to enter or exit.) As the previous example with the campfire showed, no matter (and therefore no mass) is lost through the combustion process. Read on to learn what the law of mass conservation is and how it came about.
We will also give you some examples of mass conservation laws to help you better understand the concept. In short, the mass of the reactants must be equal to the mass of the products. The law of conservation of mass and the analogous law of conservation of energy were eventually replaced by a more general principle known as mass-energy equivalence. Special relativity also redefines the concept of mass and energy, which can be used interchangeably and are defined in relation to the frame of reference. For consistency, several quantities had to be defined, such as the rest mass of a particle (mass in the rest system of the particle) and the relativistic mass (in another frame). The latter term is generally used less frequently. The law can be formulated mathematically in the fields of fluid mechanics and continuum mechanics, where the conservation of mass is usually expressed by the continuity equation, which in differential form is considered approximate and is considered part of a set of assumptions in classical mechanics. The law must be amended to conform to the laws of quantum mechanics and special relativity under the principle of mass-energy equivalence, which states that energy and mass form a conserved quantity. For very high energy systems, it is shown that the conservation of pure mass does not hold, as is the case with nuclear reactions and particle-antiparticle annihilation in particle physics. In the late 1700s, Lavoisier proved through experiments that total mass does not change in a chemical reaction, leading him to explain that matter is always conserved in a chemical reaction. For systems containing large gravitational fields, general relativity must be taken into account; Thus, mass-energy conservation becomes a more complex concept subject to other definitions, and neither mass nor energy is conserved as strictly and simply as it is in special relativity. where one molecule of methane (CH4) and two molecules of oxygen of O2 are converted into one molecule of carbon dioxide (CO2) and two molecules of water (H2O).
The number of molecules resulting from the reaction can be derived from the principle of conservation of mass, since initially four hydrogen atoms, 4 oxygen atoms and one carbon atom are present (as well as in the final state); Therefore, the number of water molecules produced must be exactly two carbon dioxide produced per molecule. In the 18th century, the principle of conservation of mass during chemical reactions was widespread and was an important hypothesis in experiments, even before a formal definition was established,[9] as seen in the work of Joseph Black, Henry Cavendish and Jean Rey. [10] The first to expound the principle was Mikhail Lomonosov in 1756. He may have demonstrated this by experiments, and had certainly discussed the principle in 1748 in correspondence with Leonhard Euler,[11] although his assertion on this subject is sometimes questioned. [12] [13] According to Soviet physicist Yakov Dorfman: To recall simply the law of conservation of mass, one could therefore say that the mass of the given reactants must be the same as that of the products. The law of conservation of mass is a useful concept in chemistry because the energy generated or consumed in a general chemical reaction constitutes a tiny amount of mass. The conservation of mass was unclear for thousands of years due to the remountable effect of the Earth`s atmosphere on the weight of gases. For example, a piece of wood weighs less after burning; This seemed to indicate that part of its mass was disappearing, transforming or being lost. This was only refuted when careful experiments were conducted in which chemical reactions such as rust were allowed to occur in sealed glass ampoules; The chemical reaction was found not to have changed the weight of the sealed container and its contents.
Weighing gases with scales was not possible until the invention of the vacuum pump in the 17th century. The law of mass conservation states that in a closed system, the mass inside the system cannot be destroyed or altered over time. Let us take the example that we discussed again. While the wax in the candle is no longer present in its original form, it is present in the room, albeit in a different form! Mass is usually not conserved, even in open systems. This is when different forms of energy and matter are allowed to enter or leave the system. However, if no radioactivity or nuclear reaction is involved, the amount of energy escaping (or entering) systems such as heat, mechanical work, or electromagnetic radiation is usually too small to be measured as a decrease (or increase) in the mass of the system. Knowledge of this scientific law is important for studying chemistry, so if you are planning to enter this field, you will definitely want to understand what the law of mass conservation is! In special relativity, conservation of mass does not apply when the system is open and energy escapes.
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