In chemistry, the word “volatile” refers to a substance that vaporizes readily. Volatility is a measure of how readily a substance vaporizes or transitions from a liquid phase to a gas phase. The term can also be applied to the phase change from solid state to vapor, which is called sublimation. A volatile substance has a high vapor pressure at a given temperature compared with a nonvolatile compound.
Examples of Volatile Substances
- Mercury is a volatile element. Liquid mercury had a high vapor pressure, readily releasing particles into the air.
- Dry ice is a volatile inorganic compound that sublimates at room temperature from the solid phase into carbon dioxide vapor.
- Osmium tetroxide (OsO4) is another volatile inorganic compound that, like dry ice, transitions from the solid phase to the vapor phase without becoming a liquid.
- Many organic compounds are volatile. An example is an alcohol. Because
volatile substancesreadily vaporize, they mix with air and may besmelled ( if theyhave an odor). Xylene and benzene are two volatile organic compoundswith distinctive scents.
Relationship Between Volatility, Temperature, and Pressure
The higher the vapor pressure of a compound, the more volatile it is. Higher vapor pressure and volatility translate into a lower boiling point. Increasing temperature increases vapor pressure, which is the pressure at which the gas phase is in equilibrium with the liquid or solid phase.