page_title: Volatility (chemistry)
section_title: Intermolecular forces
hierarchical_section_title: Volatility (chemistry) / Contributing factors / Intermolecular forces
caption_attribution_description: English: Melting points (in blue) and boiling points (in red) of the first sixteen alkanes (temperatures in °C, number of carbon atoms along the horizontal axis)
context_page_description: In chemistry, volatility is a material quality which describes how readily a substance vaporizes. At a given temperature and pressure, a substance with high volatility is more likely to exist as a vapor, while a substance with low volatility is more likely to be a liquid or solid. Volatility can also describe the tendency of a vapor to condense into a liquid or solid; less volatile substances will more readily condense from a vapor than highly volatile ones. Differences in volatility can be observed by comparing how fast a group of substances evaporate when exposed to the atmosphere. A highly volatile substance such as rubbing alcohol will quickly evaporate, while a substance with low volatility such as vegetable oil will remain condensed. In general, solids are much less volatile than liquids, but there are some exceptions. Solids that sublime such as dry ice or iodine can vaporize at a similar rate as some liquids under standard conditions.
context_section_description: An important factor influencing a substance's volatility is the strength of the interactions between its molecules. Attractive forces between molecules are what holds materials together, and materials with stronger intermolecular forces, such as most solids, are typically not very volatile. Ethanol and dimethyl ether, two chemicals with the same formula (C₂H₆O), have different volatilities due to the different interactions that occur between their molecules in the liquid phase: ethanol molecules are capable of hydrogen bonding while dimethyl ether molecules are not. The result in an overall stronger attractive force between the ethanol molecules, making it the less volatile substance of the two.
caption: Normal boiling point (red) and melting point (blue) of linear alkanes vs. number of carbon atoms.
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