Physical properties of oxygen
Oxygen is a colorless, tasteless and odorless gas that occupies about 21% (volume ratio) of air. It is chemically extremely active, has a strong ability to oxidize (that is, burn) other things, and combines with many elements. In addition, breathing plays an indispensable role in sustaining the life of living things. Industrially, it is manufactured by cooling the air and separating and purifying it together with nitrogen and argon.