Which of the following is a characteristic of all chemical changes?

• A. Change in physical state without altering chemical composition
• B. Formation of new substances with different chemical properties
• C. The process is always reversible
• D. No energy is absorbed or released

Answer: (B)

Verified step by step guidance

1. Understand that a chemical change involves a transformation where the original substances are converted into new substances with different chemical properties.
2. Recognize that a change in physical state (like melting or boiling) is a physical change, not a chemical change, because the chemical composition remains the same.
3. Know that chemical changes often involve energy changes, either absorption or release, but this is not a defining characteristic since some physical changes also involve energy changes.
4. Realize that chemical changes are not always reversible, unlike many physical changes, so reversibility is not a defining feature of chemical changes.
5. Conclude that the key characteristic of all chemical changes is the formation of new substances with different chemical properties.