triple point is the temperature and pressure at which a liquid and a gas are in equilibrium.
triple point is the temperature and pressure at which a liquid and a gas are in equilibrium.
the temperature and pressure at which a liquid and a gas are in equilibrium?
triple point
as can be seen from the above plot of the logarithm of the vapor pressure vs. the temperature for any given pure chemical compound, its normal boiling point can serve as an indication of that compound's overall volatility. a given pure compound has only one normal boiling point, if any, and a compound's normal boiling point and melting point can serve as characteristic physical properties for that compound, listed in reference books. the higher a compound's normal boiling point, the less volatile that compound is overall, and conversely, the lower a compound's normal boiling point, the more volatile that compound is overall. some compounds decompose at higher temperatures before reaching their normal boiling point, or sometimes even their melting point. for a stable compound, the boiling point ranges from its triple point to its critical point, depending on the external pressure. beyond its triple point, a compound's normal boiling point, if any, is higher than its melting point. beyond the critical point, a compound's liquid and vapor phases merge into one phase, which may be called a superheated gas. at any given temperature, if a compound's normal boiling point is lower, then that compound will generally exist as a gas at atmospheric external pressure. if the compound's normal boiling point is higher, then that compound can exist as a liquid or solid at that given temperature at atmospheric external pressure, and will so exist in equilibrium with its vapor (if volatile) if its vapors are contained. if a compound's vapors are not contained, then some volatile compounds can eventually evaporate away in spite of their higher boiling points.
boiling point
the concentration of a vapor in contact with its liquid, especially at equilibrium, is often expressed in terms of vapor pressure, which will be a partial pressure (a part of the total gas pressure) if any other gas(es) are present with the vapor. the equilibrium vapor pressure of a liquid is in general strongly dependent on temperature. at vapor–liquid equilibrium, a liquid with individual components in certain concentrations will have an equilibrium vapor in which the concentrations or partial pressures of the vapor components have certain values depending on all of the liquid component concentrations and the temperature. the converse is also true: if a vapor with components at certain concentrations or partial pressures is in vapor–liquid equilibrium with its liquid, then the component concentrations in the liquid will be determined dependent on the vapor concentrations and on the temperature. the equilibrium concentration of each component in the liquid phase is often different from its concentration (or vapor pressure) in the vapor phase, but there is a relationship. the vle concentration data can be determined experimentally, approximated with the help of theories such as raoult's law, dalton's law, and henry's law.
vapor–liquid equilibrium