“water”的概念、定义、翻译、参考文献-科学参考

water

Chemistry

A colourless liquid, H₂O; r.d. 1.000 (4°C); m.p. 0.000°C; b.p. 100.000°C. In the gas phase water consists of single H₂O molecules in which the H–O–H angle is 105°. The structure of liquid water is still controversial; hydrogen bonding of the type H₂O…H–O–H imposes a high degree of structure and current models supported by X-ray scattering studies have short-range ordered regions, which are constantly disintegrating and re-forming. This ordering of the liquid state is sufficient to make the density of water at about 0°C higher than that of the relatively open-structured ice; the maximum density occurs at 3.98°C. This accounts for the well-known phenomenon of ice floating on water and the contraction of water below ice, a fact of enormous biological significance for all aquatic organisms.
Ice has nine distinct structural modifications of which ordinary ice, or ice I, has an open structure built of puckered six-membered rings in which each H₂O unit is tetrahedrally surrounded by four other H₂O units.
Because of its angular shape the water molecule has a permanent dipole moment and in addition it is strongly hydrogen bonded and has a high dielectric constant. These properties combine to make water a powerful solvent for both polar and ionic compounds. Species in solution are frequently strongly hydrated and in fact ions frequently written as, for example, Cu²⁺ are essentially [Cu(H₂O)₆]²⁺. Crystalline hydrates are also common for inorganic substances; polar organic compounds, particularly those with O–H and N–H bonds, also form hydrates.
Pure liquid water is very weakly dissociated into H₃O⁺ and OH⁻ ions by self ionization:
$H_{2} O ⇌ H^{+} + {OH}^{-}$
(see ionic product) and consequently any species that increases the concentration of the positive species, H₃O⁺, is acidic and species increasing the concentration of the negative species, OH⁻, are basic (see acid). The phenomena of ion transport in water and the division of materials into hydrophilic (water loving) and hydrophobic (water hating) substances are central features of almost all biological chemistry. A further property of water that is of fundamental importance to the whole planet is its strong absorption in the infrared range of the spectrum and its transparency to visible and near ultraviolet radiation. This allows solar radiation to reach the earth during hours of daylight but restricts rapid heat loss at night. Thus atmospheric water prevents violent diurnal oscillations in the earth’s ambient temperature.

Chemical Engineering

A colourless, odourless, tasteless, and non-flammable liquid with the chemical formula H₂O that covers two-thirds of the surface of the planet. With a freezing point of 0^ºC and boiling point of 100^ºC at atmospheric pressure, it is used in huge quantities in the chemical industry. It is the most commonly used solvent and has the ability to dissolve a wide range of materials. It is also extensively used as a heat transfer medium for both heating and cooling purposes. It can be converted to ice or to steam, and in some cases a supercritical state is used as a solvent. It is also used as a transport medium in conveying other materials, and widely used in cleaning process plant equipment and process materials. Depending on the application, water quality is an important consideration and there is increasing pressure to reduce the amount of water that is used. The cost of transportation and scarcity are also increasingly important considerations.

Biology

A colourless liquid, H₂O. In the gas phase water consists of single H₂O molecules in which the H-O–H angle is 105°. The structure of liquid water is still controversial; hydrogen bonding of the type H₂O…H–O–H imposes a high degree of structure (see hydrogen bond) and current models supported by X-ray scattering studies have short-range ordered regions, which are constantly disintegrating and re-forming. This ordering of the liquid state is sufficient to make the density of water at about 0°C higher than that of the relatively open-structured ice; the maximum density occurs at 3.98°C. This accounts for the well-known phenomenon of ice floating on water and the contraction of water below ice, a fact of enormous biological significance for all aquatic organisms. The collective hydrogen bonding also explains the tendency of water molecules to stay together—the phenomenon of cohesion, which is vital for the uptake of water and dissolved nutrients by plants—and also the adhesion of water molecules to vessel walls. Another consequence of the hydrogen bonding is the high specific heat of water and its large latent heat of evaporation. This means it acts as a very effective ‘heat bank’, so that oceans and other large water bodies have a moderating influence on climate by slowly absorbing or emitting heat. Similarly, water is a very effective means of evaporative cooling of surfaces, whether of a forest or an athlete. Water is a powerful solvent for both polar and ionic compounds; molecules or ions in solution are frequently strongly hydrated. Pure liquid water is very weakly dissociated into H₃O⁺ (hydroxonium) and OH⁻ (hydroxyl) ions by self-ionization and consequently any compound that increases the concentration of the positive ion, H₃O⁺, is acidic and compounds increasing the concentration of the negative ion, OH⁻, are basic (see acid). The phenomena of ion transport in water and the division of materials into hydrophilic (water loving) and hydrophobic (water hating) substances are central features of almost all biological chemistry.

Geology and Earth Sciences

The water molecule is composed of two hydrogen atoms, each of atomic weight 1.00797, combined with an oxygen atom of atomic weight 15.9994. It can occur as liquid, solid, and gas phases. It is a very powerful solvent which is responsible for the transfer of material on and below the Earth’s surface.

单词	water
释义	water Chemistry A colourless liquid, H₂O; r.d. 1.000 (4°C); m.p. 0.000°C; b.p. 100.000°C. In the gas phase water consists of single H₂O molecules in which the H–O–H angle is 105°. The structure of liquid water is still controversial; hydrogen bonding of the type H₂O…H–O–H imposes a high degree of structure and current models supported by X-ray scattering studies have short-range ordered regions, which are constantly disintegrating and re-forming. This ordering of the liquid state is sufficient to make the density of water at about 0°C higher than that of the relatively open-structured ice; the maximum density occurs at 3.98°C. This accounts for the well-known phenomenon of ice floating on water and the contraction of water below ice, a fact of enormous biological significance for all aquatic organisms. Ice has nine distinct structural modifications of which ordinary ice, or ice I, has an open structure built of puckered six-membered rings in which each H₂O unit is tetrahedrally surrounded by four other H₂O units. Because of its angular shape the water molecule has a permanent dipole moment and in addition it is strongly hydrogen bonded and has a high dielectric constant. These properties combine to make water a powerful solvent for both polar and ionic compounds. Species in solution are frequently strongly hydrated and in fact ions frequently written as, for example, Cu²⁺ are essentially [Cu(H₂O)₆]²⁺. Crystalline hydrates are also common for inorganic substances; polar organic compounds, particularly those with O–H and N–H bonds, also form hydrates. Pure liquid water is very weakly dissociated into H₃O⁺ and OH⁻ ions by self ionization: $H_{2} O ⇌ H^{+} + {OH}^{-}$ (see ionic product) and consequently any species that increases the concentration of the positive species, H₃O⁺, is acidic and species increasing the concentration of the negative species, OH⁻, are basic (see acid). The phenomena of ion transport in water and the division of materials into hydrophilic (water loving) and hydrophobic (water hating) substances are central features of almost all biological chemistry. A further property of water that is of fundamental importance to the whole planet is its strong absorption in the infrared range of the spectrum and its transparency to visible and near ultraviolet radiation. This allows solar radiation to reach the earth during hours of daylight but restricts rapid heat loss at night. Thus atmospheric water prevents violent diurnal oscillations in the earth’s ambient temperature. Chemical Engineering A colourless, odourless, tasteless, and non-flammable liquid with the chemical formula H₂O that covers two-thirds of the surface of the planet. With a freezing point of 0^ºC and boiling point of 100^ºC at atmospheric pressure, it is used in huge quantities in the chemical industry. It is the most commonly used solvent and has the ability to dissolve a wide range of materials. It is also extensively used as a heat transfer medium for both heating and cooling purposes. It can be converted to ice or to steam, and in some cases a supercritical state is used as a solvent. It is also used as a transport medium in conveying other materials, and widely used in cleaning process plant equipment and process materials. Depending on the application, water quality is an important consideration and there is increasing pressure to reduce the amount of water that is used. The cost of transportation and scarcity are also increasingly important considerations. Biology A colourless liquid, H₂O. In the gas phase water consists of single H₂O molecules in which the H-O–H angle is 105°. The structure of liquid water is still controversial; hydrogen bonding of the type H₂O…H–O–H imposes a high degree of structure (see hydrogen bond) and current models supported by X-ray scattering studies have short-range ordered regions, which are constantly disintegrating and re-forming. This ordering of the liquid state is sufficient to make the density of water at about 0°C higher than that of the relatively open-structured ice; the maximum density occurs at 3.98°C. This accounts for the well-known phenomenon of ice floating on water and the contraction of water below ice, a fact of enormous biological significance for all aquatic organisms. The collective hydrogen bonding also explains the tendency of water molecules to stay together—the phenomenon of cohesion, which is vital for the uptake of water and dissolved nutrients by plants—and also the adhesion of water molecules to vessel walls. Another consequence of the hydrogen bonding is the high specific heat of water and its large latent heat of evaporation. This means it acts as a very effective ‘heat bank’, so that oceans and other large water bodies have a moderating influence on climate by slowly absorbing or emitting heat. Similarly, water is a very effective means of evaporative cooling of surfaces, whether of a forest or an athlete. Water is a powerful solvent for both polar and ionic compounds; molecules or ions in solution are frequently strongly hydrated. Pure liquid water is very weakly dissociated into H₃O⁺ (hydroxonium) and OH⁻ (hydroxyl) ions by self-ionization and consequently any compound that increases the concentration of the positive ion, H₃O⁺, is acidic and compounds increasing the concentration of the negative ion, OH⁻, are basic (see acid). The phenomena of ion transport in water and the division of materials into hydrophilic (water loving) and hydrophobic (water hating) substances are central features of almost all biological chemistry. Geology and Earth Sciences The water molecule is composed of two hydrogen atoms, each of atomic weight 1.00797, combined with an oxygen atom of atomic weight 15.9994. It can occur as liquid, solid, and gas phases. It is a very powerful solvent which is responsible for the transfer of material on and below the Earth’s surface.
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