- boiling point
1. Physics, Chem. the temperature at which the vapor pressure of a liquid is equal to the pressure of the atmosphere on the liquid, equal to 212°F (100°C) for water at sea level. Abbr.: b.p.2. the point beyond which one becomes angry, outraged, or agitated.3. the point at which matters reach a crisis.[1765-75]
* * *Temperature at which a liquid is converted to vapour when heated.At the boiling point, addition of heat results in the transformation of the liquid into its vapour without an increase in temperature. A liquid's boiling point varies according to the liquid's characteristics and the applied pressure. Water at standard atmospheric pressure, or sea level, boils at 212 °F (100 °C), while ethanol boils at about 172 °F (78 °C). At higher altitudes, boiling points are lower and foods can take longer to cook; pressure cookers can be used to increase the pressure so that the boiling point is raised.
* * *temperature at which the pressure exerted by the surroundings upon a liquid is equalled by the pressure exerted by the vapour (vapour pressure) of the liquid; under this condition, addition of heat results in the transformation of the liquid into its vapour without raising the temperature.At any temperature a liquid partly vaporizes into the space above it until the pressure exerted by the vapour reaches a characteristic value called the vapour pressure of the liquid at that temperature. As the temperature is increased, the vapour pressure increases; at the boiling point, bubbles of vapour form within the liquid and rise to the surface. The boiling point of a liquid varies according to the applied pressure; the normal boiling point is the temperature at which the vapour pressure is equal to the standard sea-level atmospheric pressure (760 mm [29.92 inches] of mercury). At sea level, water boils at 100° C (212° F). At higher altitudes the temperature of the boiling point is lower. See also vaporization.
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