enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Krypton - Wikipedia

    en.wikipedia.org/wiki/Krypton

    Krypton, like the other noble gases, is used in lighting and photography. Krypton light has many spectral lines, and krypton plasma is useful in bright, high-powered gas lasers (krypton ion and excimer lasers), each of which resonates and amplifies a single spectral line. Krypton fluoride also makes a useful laser medium.

  3. Oxygen compounds - Wikipedia

    en.wikipedia.org/wiki/Oxygen_compounds

    Oxygen can form oxides with heavier noble gases xenon and radon, although this needs indirect methods. Even though no oxides of krypton are known, oxygen is able to form covalent bonds with krypton in an unstable compound Kr(OTeF 5) 2. One unexpected oxygen compound is dioxygenyl hexafluoroplatinate, O + 2 PtF −

  4. Biological roles of the elements - Wikipedia

    en.wikipedia.org/wiki/Biological_roles_of_the...

    A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]

  5. Noble gas - Wikipedia

    en.wikipedia.org/wiki/Noble_gas

    Under extreme conditions, krypton reacts with fluorine to form KrF 2 according to the following equation: Kr + F 2 → KrF 2. Compounds in which krypton forms a single bond to nitrogen and oxygen have also been characterized, [51] but are only stable below −60 °C (−76 °F) and −90 °C (−130 °F) respectively. [40]

  6. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium ...

  7. Noble gas compound - Wikipedia

    en.wikipedia.org/wiki/Noble_gas_compound

    The first published report, in June 1962, of a noble gas compound was by Neil Bartlett, who noticed that the highly oxidising compound platinum hexafluoride ionised O 2 to O + 2. As the ionisation energy of O 2 to O + 2 (1165 kJ mol −1) is nearly equal to the ionisation energy of Xe to Xe + (1170 kJ mol −1), he tried the reaction of Xe with ...

  8. Isotopes of krypton - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_krypton

    Krypton-81 is useful in determining how old the water beneath the ground is. [10] Radioactive krypton-81 is the product of spallation reactions with cosmic rays striking gases present in the Earth atmosphere, along with the six stable or nearly stable krypton isotopes. [11] Krypton-81 has a half-life of about 229,000 years.

  9. Cellular respiration - Wikipedia

    en.wikipedia.org/wiki/Cellular_respiration

    The reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, producing large amounts of energy (ATP). Respiration is one of the key ways a cell releases chemical energy to fuel cellular activity. The overall reaction occurs in a series of biochemical steps, some of which are redox reactions.