Final answer:
The law of conservation of mass states that the total mass of substances involved in a chemical reaction remains constant.
Step-by-step explanation:
The law of conservation of mass states that the total mass of substances involved in a chemical reaction remains constant. This means that no matter is lost or created during a chemical reaction.
For example, when magnesium metal reacts with oxygen to form magnesium oxide, the mass of the products (magnesium oxide) will be equal to the mass of the reactants (oxygen gas and magnesium metal). This principle applies to all chemical reactions.
In another example, when bread dough is baked in the oven, the mass of the baked loaf will be the same as the mass of the original dough, despite the physical changes that occur during the baking process.