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Liquid oxygen has a clear cyan color and is strongly paramagnetic: it can be suspended between the poles of a powerful horseshoe magnet. [2] Liquid oxygen has a density of 1.141 kg/L (1.141 g/ml), slightly denser than liquid water, and is cryogenic with a freezing point of 54.36 K (−218.79 °C; −361.82 °F) and a boiling point of 90.19 K (−182.96 °C; −297.33 °F) at 1 bar (14.5 psi).
A steady stream of oxygen gas is then produced by the exothermic reaction. Oxygen, as a mild euphoric, has a history of recreational use in oxygen bars and in sports. Oxygen bars are establishments found in the United States since the late 1990s that offer higher than normal O 2 exposure for a minimal fee. [121]
The two singlet-triplet transitions are forbidden both because of the spin selection rule ΔS = 0 and because of the parity rule that g-g transitions are forbidden. [11] The singlet-singlet transition between the two excited states is spin-allowed but parity-forbidden. The lower, O 2 (1 Δ g) state is commonly referred to as singlet oxygen.
superoxide (O − 2) is produced by reduction of O 2. [4] Several grams are produced per day in the human body within the mitochondria. [5] O 2 + e − → O − 2. Competing with its formation, superoxide is destroyed by the action of superoxide dismutases, enzymes that catalyze its disproportionation: 2 O − 2 + 2H + → O 2 + H 2 O 2
For example, 50 g of zinc will react with oxygen to produce 62.24 g of zinc oxide, implying that the zinc has reacted with 12.24 g of oxygen (from the Law of conservation of mass): the equivalent weight of zinc is the mass which will react with eight grams of oxygen, hence 50 g × 8 g/12.24 g = 32.7 g.
The density of stishovite is 4.287 g/cm 3, which compares to α-quartz, the densest of the low-pressure forms, which has a density of 2.648 g/cm 3. [15] The difference in density can be ascribed to the increase in coordination as the six shortest Si–O bond lengths in stishovite (four Si–O bond lengths of 176 pm and two others of 181 pm) are ...
Besides active site density, the electron configuration of M center in M-N 4 active site also plays an important role in the activity and stability of an oxygen reduction reaction catalyst. Because the electron configuration of M center can affects the redox potential, which determines the activation energy of the oxygen reduction reaction. To ...
In industries, oxygen evolution reaction (OER) is a limiting factor in the process of generating molecular oxygen through chemical reactions such as water splitting and electrolysis, and improved OER electrocatalysis is the key to the advancement of a number of renewable energy technologies such as solar fuels, regenerative fuel cells and metal ...