Final answer:
The law of conservation of matter states that matter cannot be created or destroyed, but it can be changed from one form to another.
Step-by-step explanation:
The law of conservation of matter states that matter cannot be created or destroyed, but it can be changed from one form to another. In chemical reactions, the number of atoms of each element in the reactants must be the same as the number of atoms of each element in the products.
This means that the mass of a closed system of substances will remain constant, regardless of the processes acting inside the system. For example, when wood is burned, it undergoes a chemical reaction and is transformed into carbon dioxide and water vapor, but the total mass of the products is the same as the total mass of the reactants.