Vapor

Definition

Vapor is the gaseous state of a substance that is typically liquid or solid under standard conditions. It occurs when molecules escape from the liquid or solid phase into the gas phase.

5 Must Know Facts For Your Next Test

1. Vaporization includes both evaporation and boiling, which are processes where a liquid turns into vapor.
2. The amount of vapor present in the air can be measured by humidity.
3. The critical temperature is the highest temperature at which a substance can exist as a liquid and beyond which it becomes a supercritical fluid.
4. Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid phase at a given temperature.
5. During condensation, vapor changes back to liquid, releasing latent heat.

Review Questions

• What is the difference between evaporation and boiling?
• How does vapor pressure relate to temperature?
• Describe what happens during condensation.

Related terms

Evaporation: The process through which molecules at the surface of a liquid gain enough energy to enter the gaseous phase.

Boiling Point: The temperature at which a liquid's vapor pressure equals external pressure, causing it to form bubbles and transition to gas.

Condensation: The process by which vapor loses energy and transitions back into the liquid state.