This quantity for a solution is the sum, over each component species, of the mole fraction times this quantity, according to Raoult's Law.
Azeotropes are classified as positive or negative based on this quantity. Relative volatility, symbolized alpha, is the ratio of this quantity for two components in a mixture; as alpha approaches one, distillation becomes more difficult. The derivative of this quantity with respect to temperature is proportional to enthalpy by the Clausius-Clapeyron equation. Weaker intramolecular forces, larger surface area, and higher temperature all increase this quantity. This quantity for a solution is the sum, over each component species, of the mole fraction times this quantity, according to Raoult's Law. For 10 points, name this quantity which represents the equilibrium between gaseous and non-gaseous phases, which equals the atmospheric pressure at the boiling point of a liquid.
Azeotropes are classified as positive or negative based on this quantity.
{vapor pressure} (prompt on “pressure”; accept {boiling point} before “ratio”)