14. In which phase change is energy being released to the surroundings?
Answer: D
Energy is released to the surroundings during the phase change of rain turning into ice when it hits a cold surface.
When rain encounters a cold surface, it undergoes freezing, a process in which energy is released to the surroundings as the water transitions from a liquid state to a solid state.
A) Water in sweat becoming a gas as the sweat dries
This option describes evaporation, a phase change where energy is absorbed by the water as it transitions from liquid to gas. Therefore, energy is not being released; instead, it is being taken in from the surroundings.
B) A solid iron bar becoming liquid as it is heated
In this scenario, the solid iron bar is melting, which requires the absorption of energy to break the intermolecular bonds in the solid state. Consequently, energy is not released but rather consumed during this process.
C) Rubbing alcohol turning into gas when it is applied to a warm surface
This option also involves evaporation, where the rubbing alcohol absorbs energy from the warm surface to transition from liquid to gas. Thus, energy is not being released to the surroundings in this phase change.
D) Rain turning into ice when it hits a cold surface
This is the correct answer because the process of freezing involves the release of latent heat to the surroundings as the water molecules lose energy and arrange themselves into a solid structure. Thus, energy is indeed released during this phase change.
Conclusion
The process of rain turning into ice is unique among the options as it involves the release of energy to the surroundings, confirming that freezing is an exothermic phase change. In contrast, all other options describe processes where energy is absorbed, demonstrating the importance of understanding energy transfer during phase changes.