Conservation of mass
The amount of matter an object contains. Mass is measured in kilograms (kg) or grams (g). is never lost or gained in chemical reactions. It is said that mass is always conserved. In other words, the total mass of A substance formed in a chemical reaction. at the end of the reaction is equal to the total mass of the A substance that reacts together with another substance to form products during a chemical reaction. at the beginning. This is because no All elements are made of atoms. An atom consists of a nucleus containing protons and neutrons, surrounded by electrons. are created or destroyed during chemical reactions.
The principle of conservation of mass allows you to work out the mass of one substance in a reaction if the masses of the other substances are known.
Image caption, Calcium carbonate is made up of 28 grams of calcium oxide and 22 grams of carbon dioxide
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In practice, it is not always possible to get the entire calculated amount of product from a reaction. This is because:
- A chemical reaction which can go both ways, so that products can turn back into reactants. may not be completed
- some product may be lost when it is removed from the reaction mixture
- some of the reactants may react in an unexpected way