Antoine­Laurent Lavoisier was born into a privileged family on August 26, 1743 in France’s capital city, Paris. When Antoine was only 5 years of age, his mother died leaving him with a large amount of money. Antoine started his college education at Collège des Quatre­Nations, a college of the University of Paris when he was 11 and finished when he was 18 years old. Antoine mostly studied general subjects there, and studied science in his final 2 years. At age 18, Antoine enrolled in the college’s law school, where his intent was to pursue the same career as his father. After being awarded a bachelor’s degree, he obtained a license to practice as a lawyer in 1764. Antoine published his first scientific paper in 1764, and was then elected into the French Academy of Sciences in 1769 at age 26. In 1772, Lavoisier bought a diamond and placed it in a closed glass jar, noticing that after he had used a giant magnifying glass to focus the sun’s rays on the diamond, the diamond burned and disappeared. He noted that the overall weight of the jar remained unchanged, even though the diamond had entirely disappeared. This observation led him to believe that his law of mass conservation was correct. The gas that was produced by the burning of either the diamond or the charcoal by the giant lens is now called carbon dioxide. Lavoisier realized that diamond and charcoal are different forms of the same element, and gave this element the name “carbon.”

Lavoisier’s remarkable combustion apparatus

In 1772 Lavoisier discovered that when phosphorus or sulfur are burned in air the products are acidic. The products also weigh more than the original phosphorus or sulfur, suggesting the elements combine with something in the air to produce acids, but are uncertain of what it is. In 1779, Lavoisier said that oxygen is the element released by mercury oxide, and that oxygen made up 20% of air and that it is important for combustion and respiration. He also concluded that when phosphorous or sulfur are burned in the air, the products are formed by the reaction of these elements with oxygen. In 1777, Lavoisier determined Sulfur as an element. He had performed many experiments to eventually conclude that it could not be broken down into any simpler substances. in 1778, he discovered that mercury oxide’s weight decreases when it is heated. The oxygen gas it releases has exactly the same weight as the weight lost by the mercury oxide. Lavoisier then announced a new fundamental law of nature, the law of conservation of mass. This law states that the total mass of a chemical reaction’s products is identical to the total mass of the starting materials.

After suspecting that combustion and respiration are chemically the same, he conducted an experiment involving guinea pigs with Pierre­Simon Laplace. In the experiment, they measured the amount of carbon dioxide and heat given off by the guinea pig as it breathed. They compared this to the amount of heat produced when they burned carbon to produce the same amount of carbon dioxide as had been exhaled by the guinea pig. The results recorded from this experiment allowed Lavoisier to conclude that respiration is a form of combustion.

(Lavoisier measures the oxygen in air exhaled from a man’s lungs) In another experiment with Pierre­Simon Laplace, Lavoisier found that water was produced when he burned hydrogen and oxygen. This led him to believe that water is not an element, but a compound made from the elements hydrogen and oxygen. In 1789 Lavoisier published Elementary ​ Treatise on Chemistry. In this book, Lavoisier further explained his oxygen theory of chemistry, ​ established a clear difference between a compound and an element, and provided a list of chemical elements. The list included oxygen, nitrogen, hydrogen, sulfur, phosphorus, carbon, antimony, cobalt, copper, gold, iron, manganese, molybdenum, nickel, platinum, silver, tin, tungsten, and zinc. Starting in 1791, Lavoisier and the Committee of the French Academy of Sciences helped develop the metric system of measurement. In 1794, the revolutionaries sentenced Lavoisier to death after he supported foreign scientists, whom the revolutionaries wished to strip of their assets. He died on May 8, 1794 in Paris at the age of 50.