Law of Conservation of Mass: Lavoisier's Law

Law of conservation of mass: Lavoisier's law

The Law of Conservation of Mass is one of the fundamental principles in the field of chemistry. Also known as the law of conservation of matter or Lavoisier's law, after Antoine Lavoisier, the French chemist considered the father of modern chemistry.

This law establishes that the total mass of the substances that participate in a chemical reaction remains constant before and after said reaction.

What Does the Law of Conservation of Mass Say?

The Law of Conservation of Mass is based on the idea that matter cannot be created or destroyed, only transformed. In other words, the total mass of the reactants in a chemical reaction must equal the total mass of the resulting products.

This means that although atoms can rearrange and form new molecules during a reaction, the sum of their masses will remain constant.

Discoverer of the Law of Matter: Antoine Lavoisier

This law was formulated by Antoine Lavoisier in the late 18th century, when he was conducting detailed experiments to understand chemical reactions and the changes associated with them.

His work revolutionized chemistry by rejecting the "phlogiston" theory, which held that a substance called phlogiston was released during combustion. Lavoisier showed that combustion actually involved the combination of a substance with oxygen from the air, resulting in an increase in mass.

How Was the Law of Conservation of Mass Discovered?

Lavoisier carried out a series of investigations in which he analyzed different chemical reactions and studied the changes in the masses of the reactants and the products involved. One of his best known experiments was the combustion of phosphorus in a closed container.

During this experiment, Lavoisier noticed that the mass of the system (the container and the air contained in it) did not change before and after the combustion of the phosphorus. Despite the appearance of flames and sparks, the total mass remained constant. This led him to conclude that mass is neither created nor destroyed during a chemical reaction, but simply transformed.

Based on these experiments and observations, Lavoisier formulated the Law of Conservation of Matter, which states that the total mass of an isolated system remains constant before and after any chemical process or reaction.

Examples and Applications of Lavoisier's Law

The Law of Conservation of Mass has important implications for solving chemical problems. In addition, it has various practical applications in everyday life and in industry. Some of them are the following:

  1. Balance of chemical equations: The Law of Conservation of matter is used to balance chemical equations, which allows knowing the exact proportions in which reactants combine to form products.

  2. Chemical analysis: Analytical methods are based on the Law of Conservation of Mass to determine the amount of a substance present in a sample. These methods are widely used in laboratories and in industry for quality control and scientific research.

  3. Wastewater treatment: In wastewater treatment processes, principles based on this law of chemistry are applied to remove contaminants and ensure environmental protection.

  4. Power Production: Power generation, whether through the burning of fossil fuels or through renewable sources, is subject to Lavoisier's Law. This law helps to understand how chemical and physical reactions occur in energy generation processes.


Published: June 4, 2023
Last review: June 4, 2023