The Father of Modern Chemistry
A French 18th century scientist who revolutionised the study of chemistry through his systematic methods but was executed in the French Revolution.
Antoine Lavoisier was born in France in 1743. From a family of lawyer and notaries, he studied for a degree in Law, despite having a growing interest in science. At that time, while physics was becoming well-structured through the laws of Isaac Newton, chemistry was still a confused discipline, awash with unclear and fanciful theories. Lavoisier set about developing a systematic and experimental approach to the science.
His methodical experiments and conviction that there was order in chemistry led him to develop the Law of Conservation of Mass. This stated that although chemicals may change state and appearance in a chemical reaction, there is no change in the quantity of matter. He showed this in his experiments in combustion. When he burnt phosphorous and sulphur he showed that the products weighed more than the original elements. He then undertook the same experiments in sealed containers and showed that the weight gained was lost from the air.
Combustion and “Phlogiston”
His experiments in combustion lead to much greater understanding of combustion and of the composition of air. At the time there was a popular theory of combustion called the “phlogiston theory”. This suggested that all flammable substances contained a colourless, odourless, weightless substance called phlogiston which was given off when the substance was burned. Lavoisier showed that in fact part of the air was responsible for combustion.
Hydrogen and Oxygen
Lavoisier built on these discoveries when he discovered a “flammable air” which produced water when burnt in air. He began modern chemistry nomenclature when he called this “air” hydrogen, from the Greek for “water-former”. He also named the part of air which supported combustion, oxygen.
These discoveries were committed to written form in 1789 when he wrote “Elementary Treatise of Chemistry”, considered to be the first modern chemistry textbook. He also proposed a definition of elements as a substance which could not be chemically broken down any further. He also suggested a list of elements including oxygen, nitrogen, hydrogen, phosphorous, mercury, zinc and sulphur. He did, however, include on his list of elements both light and a substance called “caloric” which was considered to be a weightless gas which was transferred from one body to another when heated.
Antoine Lavoisier was a remarkable man who contributed to the progress of chemistry in many ways, by his systematic methods and also by his remarkable insights into many areas of his field. He contributed to the development of a theory of chemical bonding and also showed that diamond was in fact a form of carbon. He also contributed to biology when he showed that the respiration of animals converted oxygen to carbon dioxide in the same way as burning.
Sadly, he lived in a France which was a dangerous place. Despite being a liberal, he was involved in the taxation system and so was branded an enemy of the Republic and was executed at the guillotine in May 1794 by French revolutionaries.