When water changes from a solid to a liquid or from a liquid to a gas, what happens to its chemical structure?

• A. Water molecules rearrange to form H2O2 during state changes.
• B. The chemical structure of H2O remains unchanged.
• C. The chemical bonds within each H2O molecule are broken.
• D. The chemical structure of H2O breaks down into hydrogen and oxygen gases.

Answer: (B)

Verified step by step guidance

1. Understand that a change in state (solid to liquid or liquid to gas) is a physical change, not a chemical change.
2. Recall that in a physical change, the molecules themselves remain intact; only the arrangement and energy of the molecules change.
3. Recognize that water (H2O) molecules do not break apart or rearrange into different molecules during melting or boiling.
4. Note that the chemical bonds within each H2O molecule (the covalent bonds between hydrogen and oxygen atoms) remain unchanged during phase changes.
5. Conclude that the chemical structure of H2O remains the same, and only the physical state and molecular interactions change.