Oxygen Atomic number8Atomic weight15.9994Melting point-218.4oC (-361.1oF) Boiling point-183.0oC (-297.4oF) Density (1 atom, 0oC) 1.429 g/lValence2electronic config.2-6 or 1s22s22p4.Oxygen is one of the must important factors that made it possible for life to exist in this planet. Oxygen is also one of the elements must found in earth. Oxygen can be found in in metals, water, and even the one thin that protects us from the powerful sunrays. Oxygen is a very unstable element, which makes it easy to make compounds with other elements creating different kinds of solids and liquids. Oxygen is found in the air as O2, and found in the ozone as O3. Oxygen is essential to all planets’ life.
The Discovery of Oxygen
On August 1, 1774, Joseph Priestly examined the effect of intense heat on mercuric oxide. He noted that an air or gas was readily expelled from the specimen. To his surprise a candle burned in this with a remarkably vigorous flame. He called this new substance dephlogisticated air in terms of the current chemical theory of combustion. When he went to Paris on 1775 he showed his discovery to Antoine Lavoisier. When Antoine examined the gas he found that dephlogisticated air combined with metals and other substance. Because some of the compounds form acids he called the gas Oxygen form the Greek words for sour and I Produce.
Oxygen in the Atmosphere
The Atmosphere surrounding the earth is a mechanical mixture of gases. The most important of these gases are oxygen, nitrogen, and carbon dioxide. Oxygen is the essential element for life. It is odorless, colorless, tasteless, and slightly heavier than air. The chief commercial source of oxygen is the atmosphere. Oxygen may be separated from the mixture of gases that make up the atmosphere. This is done by physical means by subjecting air to very high pressures and low temperatures until a point is reached where it passes form the gaseous into the liquid state. Than the liquid is introduce to some warm, so that nitrogen, which has a lower boiling point then oxygen, evaporates off. Oxygen as first prepared by heating certain metals oxides, including mercury oxide.
Ozone (O3), named for the Greek word for “smell,” is a poisonous, colorless and tasteless gas with a distinctive smell. Molecules of ozone are probably the source of the smell that can be detected close to working electrical equipment such as motors and TVs. If a vehicle with a catalytic converter is started cold, ozone can be detected in the exhaust fumes. Most ozone is found high in the atmosphere in a region of the stratosphere called the ozone layer. Here ozone is vital part for life by protecting us form ultraviolet rays of the sun. Ozone absorbs the ultraviolet rays, which are harmful to both plat life and animal life. Ozone is usually prepared by passing a silent electric discharge through oxygen. Because of its powerful oxidizing properties ozone is widely used for sterilizing water and for air purification. It also is applied in organic chemistry in ozonosis, which is the reaction of ozone with unsaturated compounds such as the hydrocarbon ethylene.
Oxides are any of a large and important class of chemical compounds in which oxygen is combined with another element. Almost all elements form oxides, which vary in properties according to the element. Metal oxides are crystalline solids that contain a metal cation and the oxide anion O2. They usually react with acids to form salt or with water to form bases. For example, calcium oxide (CaO) reacts with water to form calcium hydroxide (Ca (OH2)), and if it is combined with hydrochloric acid it forms calcium carbonate (CaCl2), a salt. Nonmetal oxides are volatile compounds in which the oxygen atoms are linked covalently to the nonmetal atom. They react with bases to form salts and with water to form acids. For example, sulfur trioxide (SO3) reacts with water to form sulfuric acid (H2SO4), and reacts with sodium hydroxide to form sodium sulfate (Na2SO4), a salt. There also amphoteric oxides they contain oxygen along with cations such as aluminum, tin, or zinc: they react either with acids or with water to form salts. For example, aluminum oxide (Al2O3) reacts with hydrochloric acid to form aluminum