Equations for vapour pressure versus temperature: derivation and use of the Antoine equation on a hand-held programmable calculator.

The Antoine equation is a semi-empirical equation which expresses vapour pressure as a function of temperature. A new, rapid and highly accurate method for obtaining its three constants from experimental data is presented and applied to ethanol, water and 14 anaesthetic substances. Alternative vapour pressure equations are discussed and references for original temperature--vapour pressure data are summarized. A series of equations utilizing vapour pressure is detailed: these formulas are of use in both the practice and teaching of anaesthesia.