Science
What is The conservation of mass?
The conservation of mass is the principle that matter cannot be created or destroyed in a chemical reaction — only rearranged. The total mass of the substances before a reaction equals the total mass after, even as new substances form.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains the conservation of mass.
Key things to understand
- 1Matter isn't created or destroyed in reactions.
- 2Atoms are just rearranged into new substances.
- 3Total mass before = total mass after a reaction.
- 4It's a foundation of chemistry and balancing equations.
Frequently asked questions
- What is the conservation of mass?
- The principle that the total mass stays the same in a chemical reaction — matter is only rearranged.
- Who discovered the conservation of mass?
- Antoine Lavoisier is credited with establishing it in the 18th century.
- Why does mass stay the same in a reaction?
- Because atoms are neither created nor destroyed — they just recombine into different molecules.