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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 ...
In organic chemistry and biochemistry, important examples include amino acids and derivatives of citric acid. Although an amphiprotic species must be amphoteric, the converse is not true. For example, a metal oxide such as zinc oxide, ZnO, contains no hydrogen and so cannot donate a proton. Nevertheless, it can act as an acid by reacting with ...
By some definitions, "organic" compounds are only required to contain carbon. However, most of them also contain hydrogen, and because it is the carbon-hydrogen bond that gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry. [ 92 ]
Hydrogen forms a vast array of compounds with carbon called the hydrocarbons, and an even vaster array with heteroatoms that, because of their general association with living things, are called organic compounds. [12] The study of their properties is known as organic chemistry [13] and their study in the context of living organisms is known as ...
The metal, or various compounds, can be toxic to humans. [13] In plants, aluminum can be the primary limitation on growth in acidic soils. [14] antimony: 51: 2c: Has no known biological role, but has a variety of uses in medicine, e.g. antibacterial. [15] Some compounds are highly toxic to humans. [11] argon: 18: 2: None known. [11] None known ...
decomposition of organic matter; biological activity; Serpentinization is thought to produce approximately 80% of the world's hydrogen, especially as seawater interacts with iron- and magnesium-rich (ultramafic) igneous rocks in the ocean floor. Current models point towards radiolysis as the source of most other natural hydrogen.
Water is amphoteric, meaning that it can exhibit properties of an acid or a base, depending on the pH of the solution that it is in; it readily produces both H + and OH − ions. [c] Related to its amphoteric character, it undergoes self-ionization. The product of the activities, or approximately, the concentrations of H + and OH −
Water is an inorganic compound with the chemical formula H 2 O.It is a transparent, tasteless, odorless, [c] and nearly colorless chemical substance.It is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent [20]).