Which of the following statements about chemical changes is correct?

• A. No energy is absorbed or released during a chemical change.
• B. Chemical changes are always reversible by simple physical means.
• C. Chemical changes do not alter the chemical composition of a substance.
• D. A chemical change results in the formation of one or more new substances with different chemical properties.

Answer: (D)

Verified step by step guidance

1. Understand the definition of a chemical change: it involves the transformation of substances into new substances with different chemical properties and compositions.
2. Evaluate the first statement: 'No energy is absorbed or released during a chemical change.' Recall that chemical changes often involve energy changes, either absorption or release, so this statement is incorrect.
3. Evaluate the second statement: 'Chemical changes are always reversible by simple physical means.' Consider that many chemical changes are not easily reversible by physical methods, unlike physical changes, so this statement is incorrect.
4. Evaluate the third statement: 'Chemical changes do not alter the chemical composition of a substance.' Since chemical changes do alter the chemical composition by forming new substances, this statement is incorrect.
5. Confirm that the correct statement is: 'A chemical change results in the formation of one or more new substances with different chemical properties,' which aligns with the fundamental concept of chemical reactions.