Chemistry – Oxygen – Notes For W.B.C.S. Examination.
রসায়নের নোট – অক্সিজেন – WBCS পরীক্ষার জন্য ।
- Oxygen is the member of group 16 on the periodic table; however, most of the time, it is treated differently from its group.Continue Reading Chemistry – Oxygen – Notes For W.B.C.S. Examination.
- The symbol of oxygen is ‘O’ and atomic number is ‘8.’
- Oxygen has about nine allotropes and the most common allotrope is diatomic oxygen (i.e. O2). Other important allotrope is Ozone i.e. O3.
- Oxygen, first time, was noticed by Swedish pharmacist Carl Wilhelm Scheele.
Salient Features of Oxygen
- Oxygen is characteristically categorized as the member of “chalcogen” group.
- The word “chalcogen” is derived from a Greek word “khalkόs,” which means “copper” and the Latin-Greek word “Genēs,” which means born or produced.
- Oxygen is a highly reactive gas (or nonmetallic element); hence, it is an oxidizing agent that readily forms oxides with most of the elements and compounds.
- Oxygen has six valence electrons.
- The melting point of oxygen is -218.80C and the boiling point is -1830C.
Occurrence of Oxygen
- With about 20.8 percent share (in total earth’s atmospheric constituents), oxygen is the second ranked element of the earth’s atmosphere.
- Oxygen occurs almost in sphere of the earth namely atmosphere, hydrosphere, and lithosphere.
- During the photosynthesis process, free oxygen is produced by all green plants.
- Oxygen occurs as constituent copper ores.
- A human body contains about 65 percent oxygen.
- By mass, almost half of the earth’s crust is composed of oxygen (i.e. its oxides).
- By mass, oxygen is the third-most abundant element that found in the universe; the first and second are hydrogen and helium accordingly.
- Oxygen (i.e. O2) is a colorless and odorless diatomic gas.
- Oxygen dissolves in water very easily; however, the solubility of oxygen in the water is temperature-dependent.
Compounds of Oxygen
- Following are the major compounds of oxygen −
- Oxide
- Peroxide
- Carbon dioxide – CO2
- Hydroxide – OH–
- Ozone – O3
- Mercury (II) oxide – HgO
- Chlorate – ClO3
- Aluminum oxide – Al2O3
- Carbon monoxide – CO
- Hypochlorite – ClO–
- Silicon dioxide – SiO2
- Hypofluorous acid – HOF
- Sodium peroxide – Na2O2
- Potassium chlorate – KClO3
- Oxygen difluoride – OF2
- Sodium oxide – Na2O
Uses of Oxygen
- Oxygen (O2) is the most essential requirements for the respiration, without it, life cannot be imagined.
- Oxygen is used in medicine.
- Oxygen therapy is typically used to treat some diseases, such as, emphysema, pneumonia, some heart disorders, etc.
- Some of the underwater activities, such as scuba diving, submarines, etc. also use artificial oxygen.
- Aircrafts, mountaineers, etc. also use artificial oxygen.
- Oxygen is also used in some of the industries, e.g. smelting of iron ore into steel – in this process, about 55% of oxygen is used.
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