In chemistry, paraffin is a term that can be used synonymously with "alkane", indicating hydrocarbons with the general formula CnH2n+2. Paraffin wax refers to a mixture of alkanes that falls within the 20 ≤ n ≤ 40 range; they are found in the solid state at room temperature and begin to enter the liquid phase past approximately 37°C.
The simplest paraffin molecule is that of methane, CH4, a gas at room temperature. Heavier members of the series, such as octane, C8H18, and mineral oil appear as liquids at room temperature. The solid forms of paraffin, called paraffin wax, are from the heaviest molecules from C20H42 to C40H82. Paraffin wax was identified by Carl Reichenbach in 1830.
Paraffin, or paraffin hydrocarbon, is also the technical name for an alkane in general, but in most cases it refers specifically to a linear, or normal alkane — whereas branched, or isoalkanes are also called isoparaffins. It is distinct from the fuel known in the United Kingdom, Ireland and South Africa as paraffin oil or just paraffin, which is called kerosene in most of the U.S., Canada, Australia and New Zealand.
The name is derived from Latin parum ("barely") + affinis, meaning "lacking affinity" or "lacking reactivity" indicating paraffin's unreactive nature )
Paraffin wax (or simply "paraffin", but see alternative name for kerosene, above) is mostly found as a white, odorless, tasteless, waxy solid, with a typical melting point between about 47 °C and 64 °C ( 117°F to 147°F), and having a density of around 0.9 g/cm3. It is insoluble in water, but soluble in ether, benzene, and certain esters. Paraffin is unaffected by most common chemical reagents, but burns readily.
Pure paraffin wax is an excellent electrical insulator, with an electrical resistivity of between 1013 and 1017 ohm metre. This is better than nearly all other materials except some plastics (notably teflon). It is an effective neutron moderator and was used in James Chadwick's 1932 experiments to identify the neutron.
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