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Infobox references. N,N-Diethyl-meta-toluamide, also called diethyltoluamide or DEET ( / diːt /, from DET, the initials of di- + ethyl + toluamide), [ 1][ 2] is the oldest, one of the most effective and most common active ingredient in commercial insect repellents.
Skin (percutaneous, dermal) absorption is the transport of chemicals from the outer surface of the skin both into the skin and into circulation. Skin absorption relates to the degree of exposure to and possible effect of a substance which may enter the body through the skin. Human skin comes into contact with many agents intentionally and ...
The molecular mass ( m) is the mass of a given molecule. The unit dalton (Da) is often used. [ 1] Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element. The derived quantity relative molecular mass is the unitless ratio of the mass of a molecule to the atomic mass ...
Water molecules stay close to each other , due to the collective action of hydrogen bonds between water molecules. These hydrogen bonds are constantly breaking, with new bonds being formed with different water molecules; but at any given time in a sample of liquid water, a large portion of the molecules are held together by such bonds. [60]
Heavy water ( deuterium oxide, 2. H. 2O, D. 2O) is a form of water whose hydrogen atoms are all deuterium ( 2. H or D, also known as heavy hydrogen) rather than the common hydrogen-1 isotope ( 1. H, also called protium) that makes up most of the hydrogen in normal water. [ 3]
In astrophysics, photodissociation is one of the major processes through which molecules are broken down (but new molecules are being formed). Because of the vacuum of the interstellar medium, molecules and free radicals can exist for a long time. Photodissociation is the main path by which molecules are broken down.
Formaldehyde is an intermediate in the oxidation (or combustion) of methane, as well as of other carbon compounds, e.g. in forest fires, automobile exhaust, and tobacco smoke. When produced in the atmosphere by the action of sunlight and oxygen on atmospheric methane and other hydrocarbons, it becomes part of smog.
Detergents. A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions. [1] There are a large variety of detergents, a common family being the alkylbenzene sulfonates, which are soap-like compounds that are more soluble in hard water, because the polar sulfonate (of detergents) is less likely than the polar carboxylate (of soap) to bind to ...