Chemical substances that alter perceptions and moods are called.

Heat is involved in chemical change in two ways; chemical changes either result in heat being added to or removed from an object, and chemical changes require a certain amount of heat before they can take place.

Answer    "a salt" would be the best answerexplanationsalts can be defined as ionic compounds that are neither acids nor bases. nacl is an example of a salt, and its ionic.an enzyme is an organic compound which is covalently bonded, not ionically bonded.acids are generally held together by covalent bondsan element does not need any bonds to exist