Final answer:
Statement D, which claims that energy can be destroyed during an ordinary chemical reaction, does not reflect the Law of Conservation of Energy. According to this law, energy cannot be created or destroyed in any chemical or physical process.
Step-by-step explanation:
The statement that does not summarize a key idea of the Law of Conservation of Energy is: D. Energy can be destroyed during an ordinary chemical reaction. This statement is incorrect because, according to the law, during a chemical or physical change, energy can be neither created nor destroyed, although it can be changed in form. This principle aligns with the first law of thermodynamics, which emphasizes that energy may transform from one form to another, but the total amount of energy within the system and its surroundings remains constant.