Which of the following best explains why the melting of ice is considered a physical change?

• A. Energy is absorbed and the chemical bonds in H2O molecules are broken.
• B. The chemical composition of H2O remains unchanged during melting.
• C. Melting of ice produces a new substance with different chemical properties.
• D. The process is irreversible and cannot be undone.

Answer: (B)

Verified step by step guidance

1. Understand the definition of a physical change: it is a change in the state or appearance of a substance without altering its chemical composition.
2. Recognize that melting ice involves changing water from solid (ice) to liquid (water), which is a change in physical state.
3. Note that during melting, the molecules of H2O do not break apart or form new substances; their chemical structure remains the same.
4. Contrast this with a chemical change, where bonds within molecules are broken or formed, resulting in new substances with different chemical properties.
5. Conclude that since the chemical composition of H2O remains unchanged during melting, melting ice is a physical change.