Water
chemical compound with raw molecular formula H₂O; main constituent of the fluids of most living organisms / From Wikipedia, the free encyclopedia
Water (H
2O) is a transparent, tasteless, odourless, and almost always colourless chemical substance and covers about 71% of Earth's surface.
| |||
Names | |||
---|---|---|---|
IUPAC name
water, oxidane | |||
Other names | |||
Identifiers | |||
| |||
3D model (JSmol) |
|||
Beilstein Reference | 3587155 | ||
ChEBI | |||
ChEMBL | |||
ChemSpider |
| ||
ECHA InfoCard | 100.028.902 | ||
Gmelin Reference | 117 | ||
PubChem CID |
|||
RTECS number |
| ||
UNII | |||
CompTox Dashboard (EPA) |
|||
SMILES
| |||
Properties | |||
H 2O | |||
Molar mass | 18.01528(33) g/mol | ||
Appearance | White crystal-like solid, almost colorless liquid with a hint of blue, colorless gas | ||
Odor | None | ||
Density | Liquid:[3] 0.9998396 g/mL at 0 °C 0.9970474 g/mL at 25 °C 0.961893 g/mL at 95 °C Solid:[4] 0.9167 g/ml at 0 °C | ||
Melting point | 0.00 °C (32.00 °F; 273.15 K) [lower-alpha 1] | ||
Boiling point | 99.98 °C (211.96 °F; 373.13 K) [5][lower-alpha 1] | ||
N/A | |||
Solubility | Poorly soluble in haloalkanes, aliphatic and aromatic hydrocarbons, ethers.[6] 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 pressure | 3.1690 kilopascals or 0.031276 atm[7] | ||
Acidity (pKa) | 13.995[8][9][lower-alpha 2] | ||
Basicity (pKb) | 13.995 | ||
Conjugate acid | Hydronium | ||
Conjugate base | Hydroxide | ||
Thermal conductivity | 0.6065 W/(m·K)[12] | ||
Refractive index (nD) |
1.3330 (20 °C)[13] | ||
Viscosity | 0.890 cP[14] | ||
Structure | |||
Hexagonal | |||
C2v | |||
Bent | |||
1.8546 D[15] | |||
Thermochemistry | |||
Std enthalpy of formation ΔfH |
−285.83 ± 0.04 kJ/mol[6][16] | ||
Standard molar entropy S |
69.95 ± 0.03 J/(mol·K)[16] | ||
Specific heat capacity, C | 75.385 ± 0.05 J/(mol·K)[16] | ||
Hazards | |||
Main hazards | Drowning Avalanche (as snow)
| ||
NFPA 704 |
| ||
Flash point | Non-flammable | ||
Related compounds | |||
Other cations | Hydrogen sulfide Hydrogen selenide Hydrogen telluride Hydrogen polonide Hydrogen peroxide | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
Y verify (what is YN ?) | |||
Infobox references | |||
No known life can live without it. Water is essential for life.[17] This has to be qualified a bit. There are some forms of life which can survive without it, but cannot reproduce without it. Since reproduction is a central part of life, it is clear that water is essential for an organism to survive and reproduce.
Lakes, oceans, seas, and rivers are made of water. Precipitation is water that falls from clouds in the sky. It may be rain if it is liquid, or it may be snow or ice frozen if it is cold. When water gets below 0 °C (32 °F), it freezes and becomes ice, the frozen kind of water. If water gets very hot (above 100 °C (212 °F), it boils and becomes steam or water vapor.
There is a water cycle.