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  2. Oxygen - Wikipedia

    en.wikipedia.org/wiki/Oxygen

    Oxygen is a chemical element; it has symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is the most abundant element in Earth's crust, and after hydrogen and helium, it ...

  3. Carbon dioxide - Wikipedia

    en.wikipedia.org/wiki/Carbon_dioxide

    Carbon dioxide is a chemical compound with the chemical formula CO 2.It is made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature, and as the source of available carbon in the carbon cycle, atmospheric CO 2 is the primary carbon source for life on Earth.

  4. Gas composition - Wikipedia

    en.wikipedia.org/wiki/Gas_composition

    The standards below are two examples of commonly used and cited publications that provide a composition for standard dry air: ISO TR 29922-2017 provides a definition for standard dry air which specifies an air molar mass of 28,965 46 ± 0,000 17 kg·kmol-1. [2] GPA 2145:2009 is published by the Gas Processors Association.

  5. Chemical formula - Wikipedia

    en.wikipedia.org/wiki/Chemical_formula

    A chemical formula used for a series of compounds that differ from each other by a constant unit is called a general formula. It generates a homologous series of chemical formulae. For example, alcohols may be represented by the formula CnH2n + 1OH (n ≥ 1), giving the homologs methanol, ethanol, propanol for 1 ≤ n ≤ 3.

  6. Atmosphere of Earth - Wikipedia

    en.wikipedia.org/wiki/Atmosphere_of_Earth

    Air pollution is the introduction of airborne chemicals, particulate matter or biological materials that cause harm or discomfort to organisms. [59] The population growth , industrialization and motorization of human societies have significantly increased the amount of airborne pollutants in the Earth's atmosphere, causing noticeable problems ...

  7. Methane - Wikipedia

    en.wikipedia.org/wiki/Methane

    Methane (US: / ˈ m ɛ θ eɪ n / METH-ayn, UK: / ˈ m iː θ eɪ n / MEE-thayn) is a chemical compound with the chemical formula CH 4 (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas.

  8. Nitrogen dioxide - Wikipedia

    en.wikipedia.org/wiki/Nitrogen_dioxide

    Properties. [edit] Nitrogen dioxide is a reddish-brown gas with a pungent, acrid odor above 21.2 °C (70.2 °F; 294.3 K) and becomes a yellowish-brown liquid below 21.2 °C (70.2 °F; 294.3 K). It forms an equilibrium with its dimer, dinitrogen tetroxide (N2O4), and converts almost entirely to N2O4 below −11.2 °C (11.8 °F; 261.9 K).

  9. Jet fuel - Wikipedia

    en.wikipedia.org/wiki/Jet_fuel

    Jet fuel is therefore defined as a performance specification rather than a chemical compound. [1] Furthermore, the range of molecular mass between hydrocarbons (or different carbon numbers) is defined by the requirements for the product, such as the freezing point or smoke point.