Which of the following best describes what happens on a molecular level during a chemical change?

• A. Only the physical state of the substance changes, not its chemical identity.
• B. Atoms are rearranged to form new substances with different chemical properties.
• C. Atoms are destroyed and disappear from the system.
• D. Molecules move faster but their chemical composition remains unchanged.

Answer: (B)

Verified step by step guidance

1. Understand that a chemical change involves the transformation of substances into new substances with different properties.
2. Recall that atoms are the fundamental units of matter and cannot be created or destroyed in a chemical reaction (law of conservation of mass).
3. Recognize that during a chemical change, atoms are rearranged to form new molecules or compounds, which results in substances with different chemical properties.
4. Distinguish chemical changes from physical changes, where only the physical state or appearance changes but the chemical identity remains the same.
5. Conclude that the best description of a chemical change at the molecular level is that atoms are rearranged to form new substances with different chemical properties.