TheInfoListRev 39

Topic summary

Properties of water

Related topics
Names Preferred IUPAC name
Water
Systematic IUPAC name
Oxidane (not in common use)
Other names
  • Hydrogen oxide
  • Hydrogen hydroxide (H2O or HOH)
  • Hydroxylic acid
  • Dihydrogen monoxide (DHMO) (parody name)
  • Dihydrogen oxide
  • Hydric acid
  • Hydrohydroxic acid
  • Hydroxic acid
  • Hydroxoic acid
  • Hydrol
  • μ-Oxidodihydrogen
  • κ-Hydroxylhydrogen(0)
  • Aqua
  • Neutral liquid
  • Oxygen dihydride (may be considered incorrect)
Identifiers
3D model (JSmol)
3587155 ChEBI
ChEMBL
ChemSpider
DrugBank
EC Number
  • 231-791-2
117 KEGG
RTECS number
  • ZC0110000
UNII
  • InChI=1S/H2O/h1H2
    Key: XLYOFNOQVPJJNP-UHFFFAOYSA-N
  • O
Properties H2OMolar mass18.015 g·mol Appearance Almost colorless or white crystalline solid, almost colorless liquid, with a hint of blue, colorless gas OdorOdorless Density
  • Liquid (1 atm, VSMOW):
  • 0.99984283(84) g/mL at 0 Â°C
  • 0.99997495(84) g/mL at 3.983035(670) Â°C (temperature of maximum density, often 4 °C)
  • 0.99704702(83) g/mL at 25 Â°C
  • 0.96188791(96) g/mL at 95 Â°C
  • Solid:
  • 0.9167 g/mL at 0 °C
Melting point0.00 Â°C (32.00 Â°F; 273.15 K) Boiling point99.98 Â°C (211.96 Â°F; 373.13 K) SolubilityPoorly soluble in haloalkanes, aliphatic and aromatic hydrocarbons, ethers.
Improved solubility in carboxylates, alcohols, ketones, amines.
Miscible with methanol, ethanol, propanol, isopropanol, acetone, glycerol, 1,4-dioxane, tetrahydrofuran, sulfolane, acetaldehyde, dimethylformamide, dimethoxyethane, dimethyl sulfoxide, acetonitrile.
Partially miscible with diethyl ether, methyl ethyl ketone, dichloromethane, ethyl acetate, bromine. Vapor pressure3.1690 kilopascals or 0.031276 atm at 25 Â°C Acidity (pKa) 13.995 Basicity (pKb) 13.995 Conjugate acidHydronium H3O (pKa = 0) Conjugate baseHydroxide OH (pKb = 0) Thermal conductivity0.6065 W/(m·K) 1.3330 (20 Â°C) Viscosity0.890 mPa·s (0.890 cP) Structure HexagonalC2vBent1.8546 DThermochemistry 75.385 ± 0.05 J/(mol·K) 69.95 ± 0.03 J/(mol·K) −285.83 ± 0.04 kJ/mol −237.24 kJ/mol Hazards Occupational safety and health (OHS/OSH):
Main hazards
NFPA 704 (fire diamond)
0
0
0
Flash pointNon-flammable Related compounds
Other anions
Related solvents
Supplementary data page Water (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 Â°C [77 Â°F], 100 kPa).
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Water (H2O) is a polar inorganic compound that is, at room temperature, a tasteless and odorless liquid, which is nearly colorless apart from an inherent hint of blue. It is by far the most studied chemical compound and is described as the "universal solvent" and the "solvent of life". It is the most abundant substance on the surface of Earth and the only common substance to exist as a solid, liquid, and gas on Earth's surface. It is also the third most abundant molecule in the universe (behind molecular hydrogen and carbon monoxide).

Water molecules form hydrogen bonds with each other and are strongly polar. This polarity allows them to dissociate ions in salts and bond to other polar substances such as alcohols and acids, thus dissolving them. Its hydrogen bonding causes its many unique properties, such as having a solid form less dense than its liquid form, a relatively high boiling point of 100 Â°C for its molar mass, and a high heat capacity.

Water is amphoteric, meaning that it can exhibit properties of an acid or a base, depending on the pH of the solution that it is in; It readily produces both H
 and OH
 ions. Related to its amphoteric character, it undergoes self-ionization. The product of the activities, or approximately, the concentrations of H
 and OH
 is a constant, so their respective concentrations are inversely proportional to each other.


Wikipedia source