Water (molecule)
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Water (H2O) | |
---|---|
General | |
Systematic name | Water |
Other names | Aqua Hydrogen oxide Hydrogen hydroxide Hydrate Oxidane Hydric acid Dihydrogen monoxide Hydrohydroxic acid μ-Oxido dihydrogen |
Molecular formula | HOH or H2O |
Molar mass | 18.01524 g·mol−1 |
Appearance | transparent, almost colorless liquid with a slight hint of blue[1] |
CAS number | [7732-18-5] |
see also | Water (data page) |
Properties | |
Density and phase | 1000 kg·m−3, liquid (4 °C) 917 kg·m−3, solid |
Melting point | 0 °C, 32 °F (273.15 K)[2] |
Boiling point | 100 °C, 212 °F (373.15 K)[2] |
Triple point | 273.16 K, 611.73 Pa |
Critical point | 647 K, 22.1 MPa |
Specific heat capacity (gas) |
cp=1970 J·kg−1·K−1 @ 300 K cv=1510 J·kg−1·K−1 @ 300 K[3] |
Specific heat capacity (liquid) |
4186 J·kg−1·K−1 |
Specific heat capacity (solid) |
2060 J·kg−1·K−1 |
Acidity (pKa) | 15.74 |
Basicity (pKb) | 15.74 |
Viscosity | 0.001 Pa·s at 20 °C |
Surface Tension at 20 °C | 7.28 N·m−1 |
Structure | |
Molecular shape | non-linear bent |
Crystal structure | Hexagonal See ice |
Dipole moment | 1.85 D |
Hazards | |
MSDS | External MSDS |
Main hazards | No known hazard |
NFPA 704 | |
RTECS number | ZC0110000 |
Supplementary data page | |
Structure and properties |
n, εr, etc. |
Thermodynamic data |
Phase behaviour Solid, liquid, gas |
Spectral data | UV, IR, NMR, MS |
Related compounds | |
Related solvents | acetone methanol |
Related compounds | water vapor ice heavy water |
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
Water (H2O, HOH) covers 70-75% of the Earth's surface as liquid and solid state. And it is part of the atmosphere as a vapor. So it is the molecule that can be found more often than any other.
At room temperature, it is a nearly colorless, tasteless, and odorless liquid. Many substances dissolve in water and it is commonly seen as the universal solvent; because of this, water in nature and in use is rarely clean, and may have some properties different than those in the laboratory. But there are many compounds that are essentially, if not completely, insoluble in water. Water is the only common, pure substance found naturally in all three states of matter—for other substances, see Chemical properties.
[change] References
- ↑ http://www.dartmouth.edu/~etrnsfer/water.htm
- ↑ 2.0 2.1 Vienna Standard Mean Ocean Water (VSMOW), used for calibration, melts at 273.1500089(10) K (0.000089(10) °C, and boils at 373.1339 K (99.9839 °C)
- ↑ Serway, Raymond A. Physics for Scientists and Engineers, third edition
[change] Other websites
- Water Structure and Behaviour A comprehensive and up-to-date NPOV resource maintained by Prof Martin Chaplin of South Bank University, UK
- A spoof site on the "dangers" of dihydrogen monoxide
- Stockholm International Water Institute (SIWI)
- Explanation of the anomalous properties of water
- Computational Chemistry Wiki