Oxygen distribution on the planet

At least half of Earth’s oxygen comes from the ocean.Scientists estimate that 50-80% of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize.

Chemical Properties of Oxygen

At standard temperature and pressure (STP), two atoms of the element bind to form dioxygen, a colorless, odorless, tasteless diatomic gas with the formula O₂. Oxygen is a member of the chalcogen group on the periodic table and is a highly reactive nonmetallic elemen

Use of oxygen

Common uses of oxygen include production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.

Oxidation-reduction reactions

An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between two species. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron. Redox reactions are common and vital to some of the basic functions of life, including photosynthesis, respiration, combustion, and corrosion or rusting.

Individual research work

About the most important properties of oxygen (breathing, burning)

Oxygen is the first element in Group 16 (VIA) of the periodic table. The periodic table is a chart that shows how chemical elements are related to each other. The elements in Group 16 are said to belong to the chalcogen family. Other elements in this group include sulfur, selenium, tellurium, and polonium. The name chalcogen comes from the Greek word chalkos, meaning «ore.» The first two members of the family, oxygen and sulfur, are found in most ores.

Oxygen is by far the most abundant element in the Earth’s crust. Nearly half of all the atoms in the earth are oxygen atoms. Oxygen also makes up about one-fifth of the Earth’s atmosphere. Nearly 90 percent of the weight of the oceans is due to oxygen. In addition, oxygen is thought to be the third most abundant element in the universe and in the solar system.

The discovery of oxygen is usually credited to Swedish chemist Carl Wilhelm Scheele (1742-86) and English chemist Joseph Priestley (1733-1804). The two discovered oxygen at nearly the same time in 1774, working independently of each other.

What is the atmosphere, the layers

The atmosphere is comprised of layers based on temperature. These layers are the troposphere, stratosphere, mesosphere and thermosphere. A further region at about 500 km above the Earth’s surface is called the exosphere.

Toxic substances in the air

Toxic, or hazardous, air pollutants cause or are suspected of causing cancer, birth defects, or other serious harms. They can be gases, like hydrogen chloride, benzene or toluene, dioxin, or compounds like asbestos, or elements such as cadmium, mercury, and chromium.