from
The Collaborative International Dictionary of English v.0.48
molecular formula \mo*lec"u*lar form"u*la\, n. (Chem.)
An expression representing the composition of elements in a
chemical substance, commonly consisting of a series of
letters and numbers comprising the atomic symbols of each
element present in a compound followed by the number of atoms
of that element present in one molecule of the substance.
Thus the molecular formula for common alcohol (ethyl alcohol)
is {C2H6O}, meaning that each molecule contains two carbon
atoms, six hydrogen atoms, and one oxygen atom. The molecular
formula may be written to provide some indication of the
actual structure of the molecule, in which case structural
units may be written separately. Thus, ethyl alcohol can also
be written as {CH3.CH2.OH} or {CH3-CH2-OH}, in which the
period or dash between functional groups indicates a single
bond between the principle atoms of each group. This formula
shows that in ethyl alcohol, the carbon of a methyl group
({CH3-}) is attached to the carbon of a methylene group
({-CH2-}), which is attached to the oxygen of a hydroxyl
group ({-OH}). A {structural formula} is a graphical
depiction of the relative positions of atoms in a molecule,
and may be very complicated.
[PJC]
from
The Collaborative International Dictionary of English v.0.48
Alcohol \Al"co*hol\ ([a^]l"k[-o]*h[o^]l), n. [Cf. F. alcool,
formerly written alcohol, Sp. alcohol alcohol, antimony,
galena, OSp. alcofol; all fr. Ar. al-kohl a powder of
antimony or galena, to paint the eyebrows with. The name was
afterwards applied, on account of the fineness of this
powder, to highly rectified spirits, a signification unknown
in Arabia. The Sp. word has both meanings. Cf. {Alquifou}.]
1. An impalpable powder. [Obs.]
[1913 Webster]
2. The fluid essence or pure spirit obtained by distillation.
[Obs.] --Boyle.
[1913 Webster]
3. Pure spirit of wine; pure or highly rectified spirit
(called also {ethyl alcohol} or {ethanol}, {CH3.CH2.OH});
the spirituous or intoxicating element of fermented or
distilled liquors, or more loosely a liquid containing it
in considerable quantity. It is extracted by simple
distillation from various vegetable juices and infusions
of a saccharine nature, which have undergone vinous
fermentation.
Note: [The ferementation is usually carried out by addition
of brewer's yeast, {Saccharomyces cerevisiae} to an
aqueous solution containing carbohydrates.]
[1913 Webster +PJC]
Note: As used in the U. S. "Pharmacop[oe]ia," alcohol
contains 91 per cent by weight of ethyl alcohol and 9
per cent of water; and diluted alcohol (proof spirit)
contains 45.5 per cent by weight of ethyl alcohol and
54.5 per cent of water.
[1913 Webster]
4. (Organic Chem.) A class of compounds analogous to vinic
alcohol in constitution. Chemically speaking, they are
hydroxides of certain organic radicals; as, the radical
ethyl forms common or {ethyl alcohol} ({C2H5.OH}); methyl
forms {methyl alcohol} ({CH3.OH}) or {wood alcohol}; amyl
forms {amyl alcohol} ({C5H11.OH}) or {fusel oil}, etc.
[1913 Webster]