Final answer:
The statement in question is the law of conservation of mass, a scientific law in chemistry that asserts the mass remains constant during chemical reactions. This law is different from a theory and can be revised if new evidence emerges.
Step-by-step explanation:
The statement "Matter is neither created nor destroyed in any chemical change" refers to the law of conservation of mass, which is a fundamental concept in chemistry. This law states that in a chemical reaction, matter is neither created nor destroyed. It is classified as a scientific law, not a theory, because it is a concise statement that predicts the outcome of a specific set of conditions and is consistently validated by experiment and observation.
During chemical reactions, the atoms in the reactants are rearranged to form the products; however, there is no change in the total mass of substances. The law is valid for chemical reactions but does not hold in nuclear reactions, where mass and energy can interconvert according to Einstein's equation E=mc². Nevertheless, in both cases, the total mass-energy is conserved.
As for scientific laws being unchangeable, while they are statements of fact based on consistent observations, they can be revised if new evidence contradicts them, proving that nothing is absolute within the realm of science.