Question

on a molecular level, how does the condensation of water vapor on a bathroom mirror warm the bathroom?
multiple choice
the latent heat is released during vapor - to - liquid phase changes.
the latent heat of vaporization is absorbed from molecules gaining molecular potential energy.
the latent heat of vaporization is released from decreased molecular potential energy.

Explanation:

When water vapor (gas) condenses to form liquid water on the mirror, it undergoes a phase change from gas to liquid. During a phase change from gas to liquid (condensation), latent heat is released. The latent heat of vaporization is the energy required for a liquid to turn into a gas. When the reverse process (gas to liquid) occurs, that same amount of latent heat (per unit mass) is released. Molecules in the gas phase have higher potential energy (due to greater separation and weaker intermolecular forces compared to the liquid phase). As they condense (come closer together and intermolecular forces become stronger), the potential energy decreases, and this "excess" energy (latent heat) is released into the surroundings (the bathroom), warming it.

Answer:

The latent heat is released during vapor - to - liquid phase changes.