Condensation

Condensation is an exothermic phase change where a gas or vapor turns into a liquid when cooled or compressed ¹.

Kinetic Particle Mechanism

Under IGCSE Kinetic Particle Theory ¹:

• Gas State: Particles move rapidly and independently with large intermolecular separations.
• Cooling: Thermal energy transfers to the surroundings, decreasing particle kinetic energy and speed.
• Liquid Formation: As particles slow down, attractive intermolecular forces draw them close together into a liquid state where particles slide past each other.

[Gas Phase: Rapid & Dispersed]      Cooling / Heat Release
     (o)         (o)            ------------------------>
           (o)                     Condensation Point
                                           ||
                                           \/
                            [Liquid Phase: Clustered & Sliding]
                                     (o) (o)  (o)
                                       (o)  (o)

Latent Heat Release

Condensation occurs at constant temperature ($\Delta T = 0$) at the condensation point (identical to the boiling point for pure substances) ². During condensation, intermolecular bond formation releases the specific latent heat of vaporization ($\Delta E = m \cdot l_v$) into the environment ². This release of latent heat makes steam burns notably more severe than boiling water burns at $100\text{ }^\circ\text{C}$.

Everyday Examples

• Formation of water droplets on a cold glass or bathroom mirror.
• Cloud, mist, and dew formation in the atmosphere when warm water vapor encounters cooler air ².

Related

• Exothermic Change - Process releasing thermal energy to the surroundings.
• Intermolecular Force - Attractive forces drawing gas particles into liquid clusters.
• Boiling - Reverse bulk phase change.
• Evaporation - Surface liquid-to-gas transition.
• Freezing - Liquid-to-solid transition.
• State of Matter - Classical states of matter.
• Chemistry - Core science area.