What is the phase change from gas to liquid called?

• A. Condensation
• B. Vaporization
• C. Melting
• D. Freezing

Answer: (A)

Condensation is the phase change when a gas becomes a liquid. This happens when the gas is cooled or compressed, so the particles slow down and their kinetic energy decreases. With less energy, the molecules are more easily attracted to each other, so they come together to form a liquid. Heat is released to the surroundings during this process, which is why condensation is exothermic. You can see it in everyday life as dew forming on grass, fog or mist on a mirror, or droplets on a cold drink. This is different from vaporization, which is a liquid turning into a gas, and from melting or freezing, which are solid↔liquid transitions.