According to the kinetic molecular theory, what does a decrease in temperature indicate about the molecules in a sample of liquid water?

• A. The average kinetic energy of the water molecules decreases.
• B. The water molecules begin to ionize more readily.
• C. The number of water molecules in the sample increases.
• D. The water molecules gain more energy and move faster.

Answer: (A)

Verified step by step guidance

1. Recall that according to the kinetic molecular theory, the temperature of a substance is directly related to the average kinetic energy of its molecules.
2. Understand that a decrease in temperature means the molecules have less thermal energy available.
3. Recognize that lower kinetic energy means the molecules move more slowly on average.
4. Note that ionization or changes in the number of molecules are not directly caused by temperature changes in this context.
5. Conclude that a decrease in temperature indicates a decrease in the average kinetic energy of the water molecules.