Antoine-Laurent Lavoisier Biography

Who Was Lavoisier in Chemistry?

Antoine-Laurent Lavoisier (1743 - 1794)
Antoine-Laurent Lavoisier (1743 - 1794). Wikimedia Commons

Antoine-Laurent Lavoisier:

Antoine-Laurent Lavoisier was a French lawyer, economist and chemist.


August 26, 1743 in Paris, France.


May 8, 1794 in Paris, France at the age of 50.

Claim to Fame:

  • Considered the Father of Chemistry for making chemistry a quantitative science from a qualitative science.
  • Authored the the first modern chemistry textbook "Elementary Treatise of Chemistry" which listed all the currently known elements.
  • First to state a conservation of mass law in chemical reactions.
  • Recognized hydrogen and oxygen were elements and together made up water.
  • Introduced the idea of allotropes when he discovered carbon and diamonds were the same material.
  • Disproved the dominant Phlogiston Theory of combustion.
  • Showed rust was formed by oxygen.
  • Believed oxygen was responsible for making acids acidic. (This was later disproved.)
  • Leader in the development of the metric system of measurement.

Phlogiston Theory:

When Lavoisier was a chemist, the dominant theory of combustion was the phlogiston theory. Phlogiston was a substance inherent in all matter that was released when something burned. Items with a lot of phlogiston burned easily. Items with little phologiston would not burn. Fires in enclosed spaces would die because the air would become saturated with phlogiston, preventing further combustion.

For example, charcoal contained a lot of phlogiston.

When burned, this phlogiston would be released and the remaining ashes were all that was left.

The problem with phlogiston theory was trying to determine how much phlogiston weighed. In some cases, such as calcinating (heating a metal in air) some metals to form a metal oxide, the weight of the oxide was higher than the original metal.

This would imply phlogiston would have a negative value for weight.

Lavoisier showed that reactions with oxygen caused oxides to form and combustion to take place. He also showed how the mass of the reactants of a chemical reaction was equal to the mass of the products. This removed the need for phlogiston to have weight, either positive or negative. When he died, phlogiston theory was still accepted, but the next generation of chemists accepted his work and phlogiston theory was gone.

Lavoisier's Execution:

The post-revolutionary French government took a dim view of foreign born scientists in France and passed a mandate that denied foreign scientists their freedom and possessions. Prior to the Revolution, Paris was considered one of best places for scientists to come from across Europe and the French Academy of Sciences was world renown. Lavoisier disagreed with the government's stance and was outspoken in the defense of foreign scientists. For this, he was branded a traitor to France and tried, convicted, and guillotined all in the same day.

The same government exonerated Lavoisier two years later.