boiling point

boiling point,

temperature at which a substance changes its state from liquid to gas. A stricter definition of boiling point is the temperature at which the liquid and vapor (gas) phases of a substance can exist in equilibrium. When heat is applied to a liquid, the temperature of the liquid rises until the vapor pressurevapor pressure,
pressure exerted by a vapor that is in equilibrium with its liquid. A liquid standing in a sealed beaker is actually a dynamic system: some molecules of the liquid are evaporating to form vapor and some molecules of vapor are condensing to form liquid.
..... Click the link for more information. of the liquid equals the pressure of the surrounding gases. At this point there is no further rise in temperature, and the additional heat energy supplied is absorbed as latent heatlatent heat,
heat change associated with a change of state or phase (see states of matter). Latent heat, also called heat of transformation, is the heat given up or absorbed by a unit mass of a substance as it changes from a solid to a liquid, from a liquid to a gas, or the
..... Click the link for more information. of vaporization to transform the liquid into gas. This transformation occurs not only at the surface of the liquid (as in the case of evaporationevaporation,
change of a liquid into vapor at any temperature below its boiling point. For example, water, when placed in a shallow open container exposed to air, gradually disappears, evaporating at a rate that depends on the amount of surface exposed, the humidity of the air,
..... Click the link for more information. ) but also throughout the volume of the liquid, where bubbles of gas are formed. The boiling point of a liquid is lowered if the pressure of the surrounding gases is decreased. For example, water will boil at a lower temperature at the top of a mountain, where the atmospheric pressure on the water is less, than it will at sea level, where the pressure is greater. In the laboratory, liquids can be made to boil at temperatures far below their normal boiling points by heating them in vacuum flasks under greatly reduced pressure. On the other hand, if the pressure is increased, the boiling point is raised. For this reason, it is customary when the boiling point of a substance is given to include the pressure at which it is observed, if that pressure is other than standard, i.e., 760 mm of mercury or 1 atmosphere (see STP). The boiling point of a solutionsolution,
in chemistry, homogeneous mixture of two or more substances. The dissolving medium is called the solvent, and the dissolved material is called the solute. A solution is distinct from a colloid or a suspension.
..... Click the link for more information. is always higher than that of the pure solvent; this boiling-point elevation is one of the colligative propertiescolligative properties,
properties of a solution that depend on the number of solute particles present but not on the chemical properties of the solute. Colligative properties of a solution include freezing point (see freezing), boiling point, osmotic pressure (see osmosis), and
..... Click the link for more information. common to all solutions.

Boiling Point

the temperature of the equilibrium transition of a liquid to vapor at constant external pressure. The abbreviations used for the term “boiling point” include bp and T_b.

Table 1. Boiling points of several substances
Substance	Bciling point (°C)
Hydrogen ...............	–252.87
Nitrogen ...............	–195.8
Argon ...............	–185.7
Oxygen ...............	–182.9
Acetone ...............	56.5
Methyl alcohol ...............	64.7
Ethyl alcohol ...............	78.4
Nitric acid ...............	83.3
Iodine ...............	183.0
Glycerol ...............	290.0
Sulfuric acid ...............	330.0
Aluminum ...............	2467
Copper ...............	2567
Iron ...............	2750
Osmium ...............	5027 ± 100
Tantalum ...............	5425 ± 100

At the boiling point, the saturated vapor pressure over the plane surface of the liquid becomes equal to the external pressure. As a result, bubbles of saturated vapor are formed throughout the volume of the liquid (see). The boiling point is a special case of a transition temperature for a first-order transition. Table 1 gives the boiling points of a number of substances at normal external pressure—that is, at a pressure of 760 mm Hg, or 101,325 newtons/m².

boiling point

[′bȯil·iŋ ‚pȯint] (physical chemistry) Abbreviated bp. The temperature at which the transition from the liquid to the gaseous phase occurs in a pure substance at fixed pressure. bubble point

boiling point

the temperature at which a liquid boils at a given pressure, usually atmospheric pressure at sea level; the temperature at which the vapour pressure of a liquid equals the external pressure

boiling point

point

[point] 1. a small area or spot; the sharp end of an object.2. to approach the surface, like the pus of an abscess, at a definite spot or place.3. a tapered, pointed endodontic instrument used for exploring the depth of the root canal in therapy" >root canal therapy; called also root canal point.point A a radiographic, cephalometric landmark, determined on the lateral head film; it is the most retruded part of the curved bony outline from the anterior nasal spine to the crest of the maxillary alveolar process.absorbent point in root canal therapy, a cone of variable width and taper, usually made of paper or a paper product, used to dry or maintain a liquid disinfectant in the canal. Called also paper point.point B a radiographic, cephalometric landmark, determined on the lateral head film; it is the most posterior midline point in the concavity between the infradentale and pogonion.boiling point the temperature at which a liquid will boil; at sea level the boiling point of water is 100°C (212°F).cardinal p's 1. the points on the different refracting media of the eye that determine the direction of the entering or emerging light rays.2. four points within the pelvic inlet— the two sacroiliac articulations and the two iliopectineal eminences.craniometric p's the established points of reference for measurement of the skull.dew point the temperature at which moisture in the atmosphere is deposited as dew.far point the most remote point at which an object is clearly seen when the eye is at rest.point of fixation 1. the point or object on which one's sight is fixed and through which the axis opticus passes.2. the point on the retina, usually the fovea, on which are focused the rays coming from an object directly regarded.freezing point the temperature at which a liquid begins to freeze, for water, 0°C (32°F); it is often used interchangeably with point" >melting point, but should be used for substances being cooled while melting point is reserved for substances being heated.gutta-percha point gutta-percha cone.ice point the true melting point of ice, being the temperature of equilibrium between ice and air-saturated water under one atmosphere pressure.isoelectric point (pI) the pH of a solution in which molecules of a specific substance, such as a protein, have equal numbers of positively and negatively charged groups and therefore do not migrate in an electric field.J point on an electrocardiogram, the junction between the end of the QRS segment and the beginning of the ST segment.jugal point the point at the angle formed by the masseteric and maxillary edges of the zygomatic bone; called also jugale.lacrimal point a small aperture on a slight elevation at the medial end of the eyelid margin, through which tears from the lacrimal lake enter the lacrimal canaliculi. See also lacrimal apparatus.point of maximal impulse the point on the chest where the impulse of the left ventricle is sometimes felt or seen most strongly, normally in the fifth costal interspace inside the mammillary line.McBurney point a point of special tenderness in appendicitis, about 4 to 5 cm from the right anterior iliac spine on a line between the spine and the navel; it corresponds to the normal position of the appendix.

McBurney's point is located midway between the anterior iliac crest and the umbilicus in the right lower quadrant. From Ignatavicius and Workman, 2002.melting point (mp) the minimum temperature at which a solid begins to liquefy; see also point" >freezing point.near point the nearest point of clear vision, the absolute near point being that for either eye alone with accommodation relaxed, and the relative near point being that for the two eyes together with employment of accommodation.nodal p's two points on the axis of an optical system situated so that a ray falling on one will produce a parallel ray emerging through the other.paper point absorbent point.pressure point 1. a point of extreme sensitivity to pressure.2. one of various locations on the body at which digital pressure may be applied for the control of hemorrhage.

Locations of pressure points. Shaded areas show the regions in which hemorrhage may be controlled by pressure at the points indicated.root canal point point (def. 3).silver point in therapy" >root canal therapy, a tapered and elongated silver plug that is cemented into the canal as a filling. Called also silver cone.trigger point a spot on the body at which pressure or other stimulus gives rise to specific sensations or symptoms.triple point the temperature and pressure at which the solid, liquid, and gas phases of a substance are in equilibrium.

boil·ing point (BP, b.p.),

the temperature at which the vapor pressure of a liquid equals the ambient atmospheric pressure.

boiling point

The temperature at which the vapour pressure of a given liquid reaches the environmental (atmospheric) pressure and boils. Water boils at 100ºC (212ºF). The boiling point of water decreases by 1ºC for every 285 m of elevation; for example, at the top of Mount Everest (8,848 m), water boils at 69ºC.

boiling point

boiling point

boiling point

boil′ing point`

boil·ing point

boiling point

boiling point

boiling point

boiling point

boiling point

boiling point,

Boiling Point

boiling point

boiling point

boiling point

point

boil·ing point (BP, b.p.),

boiling point

boiling point

Synonyms for boiling point

noun the temperature at which a liquid boils at sea level

Synonyms

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noun being highly angry or excited

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