What is condensation?

What is condensation?

• A. Vapor to liquid by removing heat
• B. Liquid to vapor by adding heat
• C. Solid to liquid by heating
• D. Liquid to solid by cooling

Answer: (A)

Condensation is the change of state from a gas (water vapor) to a liquid, which happens when heat is removed from the vapor. When air cools to its dew point, it can no longer keep all the moisture as vapor, so water molecules crowd together and form liquid droplets on surfaces. In HVAC terms, this is what creates the visible humidity droplets on a cold evaporator coil or on walls when moist air contacts a cool surface; the process also releases latent heat into the surroundings. The other options describe different phase changes: vapor turning into liquid by adding heat would be vaporization, melting is solid turning into liquid with heat, and freezing is liquid turning into solid by cooling.

Condensation is the change of state from a gas (water vapor) to a liquid, which happens when heat is removed from the vapor. When air cools to its dew point, it can no longer keep all the moisture as vapor, so water molecules crowd together and form liquid droplets on surfaces. In HVAC terms, this is what creates the visible humidity droplets on a cold evaporator coil or on walls when moist air contacts a cool surface; the process also releases latent heat into the surroundings.

The other options describe different phase changes: vapor turning into liquid by adding heat would be vaporization, melting is solid turning into liquid with heat, and freezing is liquid turning into solid by cooling.