Antoine Laurent Lavoisier

Antoine-Laurent de Lavoisier (/ləˈvwɑːzieɪ/ lə-VWAH-zee-ay; French: [ɑ̃twan lɔʁɑ̃ də lavwazje]; 26 August 1743 – 8 May 1794), also Antoine Lavoisier after the French Revolution, was a French nobleman and chemist who was central to the 18th-century chemical revolution and who had a large influence on both the history of chemistry and the history of biology. It is generally accepted that Lavoisier's great accomplishments in chemistry stem largely from his changing the science from a qualitative to a quantitative one. Lavoisier is noted for his discovery of the role oxygen plays in combustion, opposing the prior phlogiston theory of combustion. He named oxygen (1778), recognizing it as an element, and also recognized hydrogen as an element (1783). By using more precise measurements than previous experimenters, he confirmed the developing theory that, although matter in a closed system may change its form or shape, its mass always remains the same (now known as the law of conservation of mass), which led to the development of the balanced physical and chemical reaction equations that we still use today.