Posted about 5 years ago
With all due respect, the previous poster is incorrect. In condensation, intramolecular bonds form between water molecules in the gas phase, and the increased attraction between these molecules causes them to enter the liquid phase. Remember, breaking bonds requires energy while forming bonds releases energy. Condensation involves the formation of bonds which makes it exothermic, so condensation causes the system to gain heat on a thermodynamic level. The reason it is likely to happen in a cold environment is because the cold causes the water particles to lose kinetic energy, reducing their speed and making them more susceptible to hydrogen-bonding attraction. Therefore condensation is commonly observed under cold circumstances, but the actual process of condensation results in a negative enthalpy change for the system, or essentially a release in heat.