Which of the following actions will increase the kinetic energy of water molecules?

• A. Adding salt to the water
• B. Decreasing the volume at constant temperature
• C. Heating the water
• D. Placing the water in a vacuum

Answer: (C)

Verified step by step guidance

1. Understand that the kinetic energy of molecules is directly related to their temperature. The higher the temperature, the greater the average kinetic energy of the molecules.
2. Analyze the effect of adding salt to water: Adding salt changes the solution's properties but does not directly increase the kinetic energy of the water molecules unless it affects temperature.
3. Consider decreasing the volume at constant temperature: At constant temperature, the average kinetic energy of molecules remains the same, even if the volume changes.
4. Evaluate heating the water: Increasing the temperature by heating directly increases the kinetic energy of the water molecules because kinetic energy is proportional to temperature.
5. Examine placing the water in a vacuum: Removing pressure by placing water in a vacuum does not inherently increase the kinetic energy of the molecules unless it causes a temperature change.