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  2. Chemical compound - Wikipedia

    en.wikipedia.org/wiki/Chemical_compound

    [16] [17] [18] A molecule may be homonuclear, that is, it consists of atoms of one chemical element, as with two atoms in the oxygen molecule (O 2); or it may be heteronuclear, a chemical compound composed of more than one element, as with water (two hydrogen atoms and one oxygen atom; H 2 O). A molecule is the smallest unit of a substance that ...

  3. List of human blood components - Wikipedia

    en.wikipedia.org/wiki/List_of_human_blood_components

    Compound Comments In whole blood (g/cm 3) In plasma or serum (g/cm 3) Water: Solvent 0.81-0.86 0.93-0.95 Acetoacetate: Produced in liver 8-40 × 10 −7: 4-43 × 10 −7: Acetone: product of bodyfat breakdown 3-20 × 10 −6: Acetylcholine: Neurotransmitter of the parasympathetic nervous system: 6.6-8.2 × 10 −8: Adenosine triphosphate ...

  4. Molecule - Wikipedia

    en.wikipedia.org/wiki/Molecule

    A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O 2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H 2 O).

  5. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    The main elements that comprise the human body (including water) can be summarized as CHNOPS. Element Symbol percent mass percent atoms Oxygen O 65.0 24.0 Carbon C 18.5 12.0 Hydrogen H 9.5 62.0 Nitrogen N 2.6 1.1 Calcium Ca 1.3 0.22 Phosphorus P 0.6 0.22 Sulfur S 0.3 0.038 Potassium K 0.2 0.03 Sodium Na 0.2 0.037 Chlorine Cl 0.2 0.024 Magnesium Mg

  6. Hypothetical types of biochemistry - Wikipedia

    en.wikipedia.org/wiki/Hypothetical_types_of...

    The ammonia molecule (NH 3), like the water molecule, is abundant in the universe, being a compound of hydrogen (the simplest and most common element) with another very common element, nitrogen. [51] The possible role of liquid ammonia as an alternative solvent for life is an idea that goes back at least to 1954, when J. B. S. Haldane raised ...

  7. Chemical substance - Wikipedia

    en.wikipedia.org/wiki/Chemical_substance

    Typically these have a metal, such as a copper ion, in the center and a nonmetals atom, such as the nitrogen in an ammonia molecule or oxygen in water in a water molecule, forms a dative bond to the metal center, e.g. tetraamminecopper(II) sulfate [Cu(NH 3) 4]SO 4 ·H 2 O. The metal is known as a "metal center" and the substance that ...

  8. Blood - Wikipedia

    en.wikipedia.org/wiki/Blood

    The formed elements are the two types of blood cell or corpuscle – the red blood cells, (erythrocytes) and white blood cells (leukocytes), and the cell fragments called platelets [12] that are involved in clotting. By volume, the red blood cells constitute about 45% of whole blood, the plasma about 54.3%, and white cells about 0.7%.

  9. Alkali metal - Wikipedia

    en.wikipedia.org/wiki/Alkali_metal

    The alkali metal peroxides are ionic compounds that are unstable in water. The peroxide anion is weakly bound to the cation, and it is hydrolysed, forming stronger covalent bonds. Na 2 O 2 + 2H 2 O → 2NaOH + H 2 O 2. The other oxygen compounds are also unstable in water. 2KO 2 + 2H 2 O → 2KOH + H 2 O 2 + O 2 [144] Li 2 O + H 2 O → 2LiOH