When a liquid undergoes a phase change to become a gas, how are energy and temperature affected during the process?

• A. Energy is released by the liquid, and the temperature increases during the phase change.
• B. Energy is absorbed by the liquid, and the temperature increases continuously during the phase change.
• C. Energy is released by the liquid, but the temperature remains constant during the phase change.
• D. Energy is absorbed by the liquid, but the temperature remains constant during the phase change.

Answer: (D)

Verified step by step guidance

1. Understand that during a phase change from liquid to gas (vaporization or boiling), the substance undergoes a transformation that requires energy input without a change in temperature.
2. Recall that the energy absorbed during this process is called the latent heat of vaporization, which is used to overcome intermolecular forces rather than increasing kinetic energy (temperature).
3. Recognize that temperature remains constant during the phase change because all the energy goes into breaking intermolecular bonds, not into increasing molecular motion.
4. Note that once the phase change is complete, any additional energy absorbed will then increase the temperature of the gas.
5. Summarize that energy is absorbed by the liquid during vaporization, but the temperature remains constant throughout the phase change.