Law of conservation of mass

What was discovered

In every chemical reaction the total mass of the reactants equals that of the products: nothing is created or destroyed. It turns the balance into chemistry's central instrument and makes stoichiometry possible.

Mikhail Lomonosov had stated it in 1756 without it becoming known in the West.

What it led to

• Stoichiometry
• Balanced chemical equations
• Quantitative analysis

Built on

• precision balance
• Black and Cavendish's experiments

Made possible

• Law of definite proportions1797
• Carathéodory's axiomatic foundations of thermodynamics1909
• industrial process accounting
• gravimetric analytical chemistry

📄 Original publication

Links

Sources✓ verified 2026-09-25

• https://en.wikipedia.org/wiki/Conservation_of_mass
• https://www.acs.org/education/whatischemistry/landmarks/lavoisier.html