9 julio, 2024

Chemistry stages: what are they

The stages of chemistry They can be divided into primitive, Greek, alchemist, Renaissance, pre-modern, and modern. In their attempt to understand the energy that moves the world, humanity has focused on matter to investigate what it is made of and how it reacts under various conditions.

Thanks to the self-preservation instinct, and later using the tools of the scientific method, from observation to the creation of universal laws, chemistry developed.

From prehistory to modernity, many fans and researchers have shed light on the development of an exciting trade that soon became a science.

Main stages of chemistry

primitive stage

In prehistory, the fight for survival led the human being to the discovery of fire. The origin of chemistry is located in this natural discovery, clearly manifesting the transformation of matter.

Around 2,000 years BC, in China, products were manufactured that led to the deduction of the use of chemistry, such as the production of artificial silk, gunpowder and porcelain, which undoubtedly required the fusion of various elements.

In the same way, in Egypt elements used in religious rituals worked in metal were elaborated, paints were used, pottery was developed, fabrics were made and it was possible to demonstrate the use of glass, and also mummification.

In ancient Babylon, for example, beers and wines, ceramics and vitrified clay were made with which they covered facades. All this was the result of chemical processes.

The Bronze and Iron Ages show the human interest in transforming matter and manufacturing new tools that would be useful for their various activities: hunting, agriculture or war.

greek stage

Between the years 650 and 350 BC, chemistry was developed in Greece. Although it was Democritus and Aristotle who first approached it, it was Empedocles who affirmed that matter was not a single thing, but was actually made up of four elements: earth, air, water and fire.

The study of chemistry during this period took place at a theoretical level, with debates and dissertations between the positions of those who affirmed that matter was the same unit, that it presented itself continuously, and those who defended an atomic conception, presenting, among others, the ether as an element in which another type of matter resided.

Thanks to the material collected in the library of Alexandria it was possible to transmit the knowledge of the East to the West on the theorization related to chemistry.

Alchemist stage: 350 BC to 1500 AD

At this time, chemistry, then called alchemy, pursued the transmutation of various materials into gold, that is, in search of the philosopher’s stone, that substance that would make it possible to obtain noble metals, such as gold or silver, from other . Although such a substance was never found, that search led to immense advances in chemical studies.

Although its history is very old, alchemy gained followers and fame during the High Middle Ages. Contrary to the Greek period, during the alchemist stage, theory was on the sidelines because all efforts were concentrated on experimentation.

From these numerous experiments important laboratory techniques were achieved, such as the separation of elements and distillation processes.

renaissance stage

Without leaving experimentation, the Renaissance conditioned knowledge to the use of reason. It was not just a matter of observing the transformations of matter, but of wondering why chemical reactions occurred.

During this period metallurgy and mainly pharmacology were modernized. Paracelsus (1493-1541), a Swiss doctor and alchemist, created yatrochemistry, which consisted of using chemistry to obtain medicines of mineral origin, as opposed to medicines of plant origin.

Paracelsus believed that the disease was produced by a chemical absence and to cure it it was necessary to use chemical products.

premodern stage. The phlogiston theory: 1660-1770

Created by George Stahl (1659-1734), the phlogiston theory was intended to provide a scientific answer to the phenomenon of fire.

He studied the caloric phenomena that came into play in the combustion of metals, the release of heat, the transformation of materials into ashes, and the appearance of fire with its changes in shapes and colors.

The element that was released during the fire was called phlogiston and it was thought that it went to the atmosphere, and although it was an erroneous theory, it was maintained during the 18th century. However, this theory left advances in techniques and a large number of experiments.

The development of chemistry went through the study of the nature of gases also in this period. It is right here when the popular phrase comes to life: “matter is neither created nor destroyed, it only transforms”.

The demonstration of the existence of atmospheric pressure occurred during this stage and the Irishman Robert Boyle (1627-1691) had a lot to do with it, who studied the pressure-volume relationship of a gas.

Stephen Hales (1677-1761), for his part, invented the pneumatic tank and demonstrated that it was possible to collect gases. Thanks to this discovery, the gases released in a reaction were collected in water and thus it was possible to study them.

Modernity: 1770 to the present

During the 18th and 19th centuries, scientists concentrated on the reactions of matter, measured with quantitative techniques.

Laws such as the law of conservation of mass, by Antoine Lavoisier, the law of multiple proportions, by John Dalton (1766-1844), and the law of definite proportions, by Louis Proust (1754-1826) were generated. It was shown that the atom was real and that it was possible to determine its weight.

Antoine Laivosier (1743-1794) was considered the creator of modern chemistry. Among other findings, he demonstrated that water was composed of hydrogen and oxygen and refuted the phlogiston theory with the oxidation theory, which explained the processes of combustion, respiration, and calcination.

In modern times, the works of Amadeo Avogadro (1776-1856) were also recognized, with studies on molecules and gases, Friedrich Whöler (1800-1882), with the synthesis of urea, Julius Meyer (1830-1895) and Dmitri Mendeléyev ( 1834-1907), with the periodic table, and August Kekulé (1829-1896), with the tetravalency of carbon and the structure of benzene, among others.

Alessandro Giuseppe Volta (1745-1827) made a battery through which an electric current was achieved. By deducing that matter had an electrical nature, investigations of electrochemical reactions became popular.

In the middle of the 19th century, the study of thermochemistry began, that is, heat processes involved in physical reactions.

Modernity also brought with it the study of atomic weight and molecular weight, and Mendeleev’s periodic law of chemical elements.

References

Bernadette B. et al (1996). A History of Chemistry. Harvard University Press.
Lecaille, C. (1994). The Phlogiston. Rise and fall of the first great chemical theory. Retrieved from magazines.unam.

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