The law of Mass Conservation is an important fundamental chemical principle. The law states that mass is neither created nor destroyed in a chemical reaction. Antione Lavoisier (1743 – 1794), a French chemist, studied combustion reactions. He was able to show that when the combustion was carried out in a closed vessel (no exchange of matter or energy), the mass of the products of combustion was equal to the mass of reactants. For the combustion of methane in oxygen, the mass of carbon dioxide and water produced is the same as the mass of the methane and oxygen reactants.
For example, if 16.0 g of methane is reacted with 64.0 g of O2 then 44.0 g of CO2 and 36.0 g of H2O are produced.
For the reaction, 80.0 g of reactants produce 80.0 g of products. You can think of a chemical reaction as a rearrangement of atoms. Nothing is gained or lost. Mass is conserved!!
Worksheet: Laws of Mass Conservation and Multiple Proportions
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