Which of the following best describes what happens to water as it evaporates?

• A. Water undergoes a chemical change and becomes ice.
• B. Water molecules are chemically broken down into hydrogen and oxygen.
• C. Water forms a new compound with air.
• D. Water undergoes a physical change from liquid to gas.

Answer: (D)

Verified step by step guidance

1. Understand the difference between physical and chemical changes: A physical change affects the form of a substance but not its chemical composition, while a chemical change results in the formation of new substances with different chemical properties.
2. Recognize that evaporation is the process where water changes from the liquid phase to the gas phase (water vapor) without altering its molecular structure (H\_2O remains H\_2O).
3. Note that during evaporation, water molecules gain enough energy to overcome intermolecular forces and enter the gas phase, but no chemical bonds within the water molecules are broken or formed.
4. Eliminate options that describe chemical changes, such as water becoming ice (which is a physical change but from liquid to solid), water breaking down into hydrogen and oxygen (a chemical decomposition), or water forming a new compound with air (which would be a chemical reaction).
5. Conclude that evaporation is best described as a physical change from liquid to gas, where the chemical identity of water remains unchanged.