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United States – NEC 2008 Table 250.122 ... United States – NFPA, IEEE STD 80, IEEE STD 80, NFPA 496, NFPA 70 [21]
Selenium pollution might impact some aquatic systems and may be caused by anthropogenic factors such as farming runoff and industrial processes. [100] People who eat more fish are generally healthier than those who eat less, [ 101 ] which suggests no major human health concern from selenium pollution, although selenium has a potential effect on ...
The standard enthalpy change of combustion, ΔH° c, expressed per mole of ammonia and with condensation of the water formed, is −382.81 kJ/mol. Dinitrogen is the thermodynamic product of combustion: all nitrogen oxides are unstable with respect to N 2 and O 2, which is the principle behind the catalytic converter.
Being a good solvent for many materials (such as grease and tar), carbon tetrachloride was widely used as a cleaning fluid for nearly 70 years. It is nonflammable and nonexplosive and did not leave any odour on the cleaned material, unlike gasoline, which was also used for cleaning at the time. It was used as a "safe" alternative to gasoline.
Abundances are given as pollution free monthly mean mole fractions in parts-per-trillion. Dichloromethane is not classified as an ozone-depleting substance by the Montreal Protocol. [43] The US Clean Air Act does not regulate dichloromethane as an ozone depleter. [44] Dichloromethane has been classified as a very short-lived substance (VSLS).
Nitrogen dioxide is a reddish-brown gas with a pungent, acrid odor above 21.2 °C (70.2 °F; 294.3 K) and becomes a yellowish-brown liquid below 21.2 °C (70.2 °F; 294.3 K). It forms an equilibrium with its dimer , dinitrogen tetroxide ( N 2 O 4 ), and converts almost entirely to N 2 O 4 below −11.2 °C (11.8 °F; 261.9 K).
The symmetry of a carbon dioxide molecule is linear and centrosymmetric at its equilibrium geometry. The length of the carbon–oxygen bond in carbon dioxide is 116.3 pm, noticeably shorter than the roughly 140 pm length of a typical single C–O bond, and shorter than most other C–O multiply bonded functional groups such as carbonyls. [19]
Ethanol-water mixtures have less volume than the sum of their individual components at the given fractions. Mixing equal volumes of ethanol and water results in only 1.92 volumes of mixture. [76] [81] Mixing ethanol and water is exothermic, with up to 777 J/mol [82] being released at 298 K. Hydrogen bonding in solid ethanol at −186 °C