* Before Lavoisier: The idea of elements transforming into each other was prevalent. For example, burning wood was thought to release a component called "phlogiston" into the air.
* Lavoisier's Experiments: He meticulously conducted experiments, particularly with combustion. He weighed reactants (like wood and oxygen) and products (like ash, carbon dioxide, and water) before and after reactions. He found that the total mass of the reactants always equaled the total mass of the products.
* The Law of Conservation of Mass: Based on his findings, Lavoisier formulated the law of conservation of mass: "In a closed system, the total mass of the reactants before a chemical reaction must equal the total mass of the products after the reaction."
Key Contributions:
* Quantitative Approach: Lavoisier emphasized precise measurements and quantitative analysis, moving chemistry away from qualitative observations.
* Focus on Oxygen: He correctly identified oxygen's role in combustion, replacing the flawed phlogiston theory.
* Foundation of Modern Chemistry: His work laid the groundwork for the development of modern chemistry, including stoichiometry (the study of the quantitative relationships between reactants and products in chemical reactions).
In essence, Lavoisier proved that matter cannot be created or destroyed in chemical reactions, only transformed. This fundamental law has become a cornerstone of chemistry.
