Monooxygen
(1) oxygen is a simple substance formed by oxygen, and its chemical formula is O2. Its chemical properties are relatively active, and most elements can react with oxygen. The activity is not very strong at room temperature, and it is not easy to react with many substances. However, it is very active at high temperature and can be directly combined with many elements, which is related to the electronegativity of oxygen atoms second only to fluorine.
(2) Oxygen is a colorless and odorless gas, which is the most common elemental form of oxygen. Melting point -2 18.4℃ and boiling point-183℃. Insoluble in water, about 30mL of oxygen is soluble in 1L water. Oxygen in the air accounts for about 2 1%. Liquid oxygen is sky blue. Oxygen fixation is a blue crystal. Oxygen is the most widely distributed element in nature, accounting for 48.6% of the earth's crust, and it is the most abundant element.
(3) Hydrocarbon oxidation, wastewater treatment, rocket propellant and breathing of animals and people in aviation, aerospace and diving all need oxygen. Animal respiration, combustion and all oxidation processes (including the decay of organic matter) will consume oxygen. But the oxygen in the air can be continuously supplemented by photosynthesis of plants. Metal cutting and welding.
(4) Oxygen with purity of 93.5%~99.2% is mixed with combustible gas (such as acetylene) to produce extremely high temperature flame, thus melting metal. The metallurgical process is inseparable from oxygen. Oxygen is also needed to strengthen the production process of nitric acid and sulfuric acid. Blowing the mixture of oxygen and steam into the gas producer instead of air can obtain high calorific value gas. Medical gas is extremely important.