What is the principle behind the law of conservation of mass?

The principle behind the law of conservation of mass is that mass is neither created nor destroyed in a chemical reaction. This fundamental concept asserts that the total mass of reactants in a chemical reaction is equal to the total mass of the products. It emphasizes that atoms are simply rearranged during chemical reactions, but their total quantity remains constant.

For example, when hydrogen gas reacts with oxygen gas to form water, the atoms of hydrogen and oxygen combine in a specific ratio, and the total mass before the reaction is identical to the mass of the water produced afterward. This principle is essential in balancing chemical equations, where it is crucial to ensure that the number of each type of atom is the same on both sides of the reaction. Understanding the conservation of mass helps scientists predict the outcomes of reactions and formulate accurate models in chemistry.