kidzsearch.com > wiki  

Ozone



KidzSearch Safe Wikipedia for Kids.
Jump to: navigation, search
Ozone
200px
Ozone-CRC-MW-3D-balls.png
Ozone-CRC-MW-3D-vdW.png
IUPAC name Trioxygen
Other names 4-trioxidiene; catena-trioxygen
Identifiers
CAS number 10028-15-6
PubChem 24823
EC number 233–069–2
MeSH Ozone
ChEBI CHEBI:25812
RTECS number RS8225000
SMILES [O-][O+]=O
Gmelin Reference 1101
Properties
Molecular formula O3
Molar mass 47.98 g mol-1
Appearance Colourless to pale blue gas<
Odor Pungent
Density 2.144 mg cm−3 (at 0 °C)
Melting point

-192 °C, 81 K, -314 °F

Boiling point

-112 °C, 161 K, -170 °F

Solubility in water 1.05 g L−1 (at 0 °C)
Solubility in other solvents Very soluble in CCl4, sulfuric acid
Vapor pressure 55.7 atm[1] (−12.15 °C or 10.13 °F; 261.00 K)[a]
+6.7·10−6 cm3/mol
Refractive index (nD) 1.2226 (liquid), 1.00052 (gas, STP, 546 nm — note high dispersion)[2]
Structure
Space group C2v
Coordination
geometry
Digonal
Molecular shape Dihedral
Hybridisation sp2 for O1
Dipole moment 0.53 D
Thermochemistry
Std enthalpy of
formation
ΔfHo298
142.67 kJ mol−1
Standard molar
entropy
So298
238.92 J K−1 mol−1
Hazards
NFPA 704

NFPA 704.svg

0
4
4
 
U.S. Permissible
exposure limit (PEL)
TWA 0.1 ppm (0.2 mg/m3)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Ozone, or trioxygen, is a chemical with the symbol O3. This means one molecule of ozone is made of three oxygen atoms. Ozone is rarely called trioxygen, even though this is its IUPAC systematic name.[3] Ozone is formed from oxygen gas (O2) by the action of ultraviolet light and also atmospheric electrical discharges. It is present in low concentrations throughout the Earth's atmosphere. In total, ozone makes up only 0.6 ppm (parts per million) of the atmosphere by volume.

Ozone is important to life on planet Earth. There is a portion of the stratosphere with a high concentration of ozone, called the ozone layer. The ozone layer filters out damaging ultraviolet radiation from the Sun,[4] like a kind of sun screen. Without this ozone layer things would not have been able to live on the surface of our planet. The ozone layer also absorbs a lot of heat from the sun's rays.

However, ozone is toxic to animals and plants above concentrations of about 0.1 ppm. In humans, it can cause nasal and throat irritation, and nausea.[5] Extended exposure can cause lung oedema.[5] 0.100 ppm is the maximum allowable limit for industrial, public, or occupied spaces in England, Japan, France, the Netherlands and Germany. The Ozone layer is in the 10 to 50 kilometer range of the Earth's atmosphere.[5]

References

Notes

  1. This vapor pressure is for the critical temperature, which is below room temperature.