When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Hydrogen safety - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_safety

    The Hindenburg disaster is an example of a large hydrogen explosion. Hydrogen safety covers the safe production, handling and use of hydrogen, particularly hydrogen gas fuel and liquid hydrogen. Hydrogen possesses the NFPA 704's highest rating of four on the flammability scale because it is flammable when mixed even in small amounts with ...

  3. Median lethal dose - Wikipedia

    en.wikipedia.org/wiki/Median_lethal_dose

    Some chemicals, such as hydrogen cyanide, are rapidly detoxified by the human body, and do not follow Haber's law. In these cases, the lethal concentration may be given simply as LC 50 and qualified by a duration of exposure (e.g., 10 minutes).

  4. 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 ...

  5. Effects of nuclear explosions on human health - Wikipedia

    en.wikipedia.org/wiki/Effects_of_nuclear...

    The main causes of death and disablement in this state are thermal burns and the failure of structures resulting from the blast effect. Injury from the pressure wave is minimal in contrast because the human body can survive up to 2 bar (30 psi) while most buildings can withstand only a 0.8 bar (12 psi) blast.

  6. 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]

  7. Hydrogen - Wikipedia

    en.wikipedia.org/wiki/Hydrogen

    Hydrogen is a chemical element; it has symbol H and atomic number 1. It is the lightest element and, at standard conditions, is a gas of diatomic molecules with the formula H 2, sometimes called dihydrogen, [11] hydrogen gas, molecular hydrogen, or simply hydrogen. It is colorless, odorless, [12] non-toxic, and highly combustible.

  8. Hydrogen sulfide - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_sulfide

    100 ppm IDLH (NIOSH): immediately dangerous to life and health (the level that interferes with the ability to escape) 0.00047 ppm or 0.47 ppb is the odor threshold, the point at which 50% of a human panel can detect the presence of an odor without being able to identify it. [67] 10–20 ppm is the borderline concentration for eye irritation.

  9. Carbon monoxide poisoning - Wikipedia

    en.wikipedia.org/wiki/Carbon_monoxide_poisoning

    Carbon monoxide has a higher diffusion coefficient compared to oxygen, and the main enzyme in the human body that produces carbon monoxide is heme oxygenase, which is located in nearly all cells and platelets. [6] Most endogenously produced CO is stored bound to hemoglobin as carboxyhemoglobin. The simplistic understanding for the mechanism of ...