Answer:
Step-by-step explanation:
Water vapor condensing to liquid water is a change of phase.
Changes of phases occur at constant temperature.
During a change of phase, subtances absorb or release energy which is what let them to modify the motion (kinetic energy) of the particles.
Exothermic processes are those in which energy is released, and so the matther ends up with less energy and the surroundings end up with more energy. On the other hand, in an endothermic process, energy is absorbed, the matter ends up with more energy and the surroundings end up with less energy.
In water vapor the molecules of water have a high kinetic energy level (molecules are moving fast). In liquid water, the molecules are more attached to each other than in water vapor and they move more slowly, so they have less kinetic energy.
Hence, the water vapor molecules must release energy when water vapor is condensing to liquid water, meaning that this is an exothermic process.