Which of the following best describes what occurs during a chemical change?

• A. Energy is always absorbed without any change in composition.
• B. The physical state of a substance changes, but its chemical identity remains the same.
• C. New substances with different chemical properties are formed.
• D. The substance undergoes a change in shape or size only.

Answer: (C)

Verified step by step guidance

1. Understand that a chemical change involves the transformation of substances into new substances with different chemical properties and compositions.
2. Recognize that during a chemical change, the original substances' chemical identities are altered, meaning bonds are broken and new bonds are formed.
3. Distinguish chemical changes from physical changes, where physical changes affect only the physical state or appearance without altering chemical identity.
4. Note that energy may be absorbed or released during a chemical change, but energy change alone does not define a chemical change.
5. Conclude that the best description of a chemical change is the formation of new substances with different chemical properties.