Which of the following best describes what happens when water freezes?

• A. The water forms a non-crystalline amorphous solid.
• B. The water molecules move faster and the temperature increases.
• C. The water evaporates rapidly due to increased kinetic energy.
• D. The molecules arrange into a crystalline structure, and the temperature remains constant until all water is solid.

Answer: (D)

Verified step by step guidance

1. Understand the phase change process: When water freezes, it undergoes a phase transition from liquid to solid.
2. Recall that during freezing, water molecules lose kinetic energy and begin to arrange themselves in an ordered, repeating pattern, forming a crystalline solid (ice).
3. Recognize that the temperature remains constant during the phase change because the energy removed from the system is used to change the phase, not to lower the temperature further. This is known as the latent heat of fusion.
4. Eliminate incorrect options: Water does not form a non-crystalline amorphous solid when freezing under normal conditions; molecules do not move faster or increase temperature during freezing; and water does not evaporate rapidly during freezing since kinetic energy decreases.
5. Conclude that the best description is that water molecules arrange into a crystalline structure, and the temperature remains constant until all water is solid.