Vapor

Properties of Vapor

• Vapor refers to a gas phase at a temperature where the same substance can also exist in the liquid or solid state, below the critical temperature of the substance.
• Gas refers to a compressible fluid phase.
• Fixed gases are gases for which no liquid or solid can form at the temperature of the gas.
• A liquid or solid does not have to boil to release a vapor.
• Vapor is responsible for cloud formation and condensation.

Vapor Pressure

• The vapor pressure is the equilibrium pressure from a liquid or a solid at a specific temperature.
• The equilibrium vapor pressure of a liquid or solid is not affected by the amount of contact with the liquid or solid interface.
• The normal boiling point of a liquid is the temperature at which the vapor pressure is equal to normal atmospheric pressure.
• For two-phase systems, the vapor pressure of the individual phases are equal.
• The vapor pressure follows Raoults law in the absence of stronger inter-species attractions between molecules.

Examples of Vapor

• Invisible water vapor condenses to form visible water droplets called mist.
• Perfumes contain chemicals that vaporize at different temperatures and rates.
• Atmospheric water vapor can condense into small liquid droplets and form fog, mist, and haar.
• Mercury-vapor lamps and sodium vapor lamps produce light from excited states of atoms.
• Flammable liquids do not burn when ignited, but the vapor cloud above the liquid can burn within certain concentration limits.

Measuring Vapor

• The amount of vapor present is quantified by the partial pressure of the gas.
• Vapors obey the barometric formula in a gravitational field.
• Vapor can be measured using various techniques and instruments.
• Vapor concentration can be determined for different purposes, such as safety assessments or chemical analysis.
• Vapor measurements are important in understanding atmospheric conditions and industrial processes.

Related Concepts

• Contrails, also known as vapor trails, are long, thin artificial clouds formed behind aircraft.
• Dilution is a chemistry concept related to vapor.
• Evaporation is a type of vaporization that occurs from the surface of a liquid.
• Henry's law is a gas law that relates to the proportionality of dissolved gas.

Vapor Data Sources