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Oxygen
Oxygen

Oxygen

Chemical formula: O2, is a colorless and odorless gas, oxygen element is the most common elemental form. Melting point-218.4℃, boiling point-183℃. Not easily soluble in water, 1L of water dissolves about 30mL of oxygen. Oxygen makes up about 21% of air, and we breathe air to get oxygen, which is necessary for almost all life processes.