During a phase change, what happens to energy?

During a phase change, what happens to energy?

• A. It is transferred, not created or destroyed
• B. It is created
• C. It disappears
• D. It becomes mass

Answer: (A)

During a phase change, energy is transferred between the substance and its surroundings, not created or destroyed. This energy is the latent heat needed to break or form the intermolecular bonds as the substance changes from one phase to another. While melting or boiling, added energy goes into changing the arrangement of the particles and keeps the temperature constant until the entire material has changed phase. Conversely, during freezing or condensation, energy is released to the surroundings, again with the temperature staying at the phase-change point until the change is complete. Mass stays the same in a phase change, and the energy changes hands rather than appearing or disappearing.

During a phase change, energy is transferred between the substance and its surroundings, not created or destroyed. This energy is the latent heat needed to break or form the intermolecular bonds as the substance changes from one phase to another. While melting or boiling, added energy goes into changing the arrangement of the particles and keeps the temperature constant until the entire material has changed phase. Conversely, during freezing or condensation, energy is released to the surroundings, again with the temperature staying at the phase-change point until the change is complete. Mass stays the same in a phase change, and the energy changes hands rather than appearing or disappearing.