| slovo | definícia |
C2H6
(gcide) | Homology \Ho*mol"o*gy\, n. [Gr. ? agreement. See Homologous.]
1. The quality of being homologous; correspondence; relation;
as, the homologyof similar polygons.
[1913 Webster]
2. (Biol.) Correspondence or relation in type of structure in
contradistinction to similarity of function; as, the
relation in structure between the leg and arm of a man; or
that between the arm of a man, the fore leg of a horse,
the wing of a bird, and the fin of a fish, all these
organs being modifications of one type of structure.
[1913 Webster]
Note: Homology indicates genetic relationship, and according
to Haeckel special homology should be defined in terms
of identity of embryonic origin. See Homotypy, and
Homogeny.
[1913 Webster]
3. (Chem.) The correspondence or resemblance of substances
belonging to the same type or series; a similarity of
composition varying by a small, regular difference, and
usually attended by a regular variation in physical
properties; as, there is an homology between methane,
CH4, ethane, C2H6, propane, C3H8, etc., all members
of the paraffin series. In an extended sense, the term is
applied to the relation between chemical elements of the
same group; as, chlorine, bromine, and iodine are said to
be in homology with each other. Cf. Heterology.
[1913 Webster]
General homology (Biol.), the higher relation which a
series of parts, or a single part, bears to the
fundamental or general type on which the group is
constituted. --Owen.
Serial homology (Biol.), representative or repetitive
relation in the segments of the same organism, -- as in
the lobster, where the parts follow each other in a
straight line or series. --Owen. See Homotypy.
Special homology (Biol.), the correspondence of a part or
organ with those of a different animal, as determined by
relative position and connection. --Owen.
[1913 Webster] |
C2H6
(gcide) | ethane \eth"ane\ ([e^]th"[=a]n), n. [From Ether.] (Chem.)
A gaseous hydrocarbon, C2H6, forming a constituent of
ordinary illuminating gas. It is the second member of the
paraffin series, and its most important derivatives are
common alcohol (ethyl alcohol), acetaldehyde, ether, and
acetic acid. Called also dimethyl.
[1913 Webster] |
c2h6
(wn) | C2H6
n 1: a colorless odorless alkane gas used as fuel [syn:
ethane, C2H6] |
| | podobné slovo | definícia |
C2H6O
(gcide) | 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] |
c2h6
(wn) | C2H6
n 1: a colorless odorless alkane gas used as fuel [syn:
ethane, C2H6] |
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