What does the principle of conservation of mass state?

The principle of conservation of mass states that mass cannot be created or destroyed in a chemical reaction; it is conserved. This fundamental concept was established by Antoine Lavoisier in the late 18th century and is foundational to both chemistry and physics. It implies that in any closed system, the total mass before a reaction takes place will be equal to the total mass after the reaction. This means that even though substances may change their form or combine in different ways during a reaction, the total quantity of matter remains constant.

This principle is vital for balancing chemical equations, as it ensures that the number of atoms for each element remains the same on both sides of the equation, confirming that no atoms are lost or gained in the process. In practical terms, this means that even when matter undergoes transformations, such as burning or reacting with other substances, the overall mass remains unchanged, affirming the conservation of mass within the system.