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OSHA requires employers who send workers into areas where the oxygen concentration is known or expected to be less than 19.5% to follow the provision of the Respiratory Protection Standard [29 CFR 1910.134]. Generally, work in an oxygen depleted environment requires an SCBA or airline respirator.
Many organisms require hypoxic conditions. Oxygen is poisonous to anaerobic bacteria for example. [3] Oxygen depletion is typically expressed as a percentage of the oxygen that would dissolve in the water at the prevailing temperature and salinity. A system with low concentration—in the range between 1 and 30% saturation—is called hypoxic ...
Pressurized aircraft cabins are typically maintained at 75 kPa, the pressure found at 2,500 m (8,200 ft) altitude, resulting in an oxygen partial pressure of about 16 kPa, which is the same as a 15% oxygen concentration in a hypoxic-air application at sea-level pressure. However, passengers are sedentary and crew members have immediate access ...
The total mass of Earth's hydrosphere is about 1.4 × 10 18 tonnes, which is about 0.023% of Earth's total mass. At any given time, about 2 × 10 13 tonnes of this is in the form of water vapor in the Earth's atmosphere (for practical purposes, 1 cubic metre of water weighs 1 tonne).
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]
The compressibility for a typical liquid or solid is 10 −6 bar −1 (1 bar = 0.1 MPa) and a typical thermal expansivity is 10 −5 K −1. This roughly translates into needing around ten thousand times atmospheric pressure to reduce the volume of a substance by one percent.
The refractive index of liquid water (1.333 at 20 °C (68 °F)) is much higher than that of air (1.0), similar to those of alkanes and ethanol, but lower than those of glycerol (1.473), benzene (1.501), carbon disulfide (1.627), and common types of glass (1.4 to 1.6). The refraction index of ice (1.31) is lower than that of liquid water.
[68] [254] The 1.5-kilometre (0.93 mi) ice layer covering the lake is composed of water ice with 10 to 20% admixed dust, and seasonally covered by a 1-metre-thick (3 ft 3 in) layer of CO 2 ice. [68] Since the raw-data coverage of the south polar ice cap is limited, the discoverers stated that "there is no reason to conclude that the presence of ...