| 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.
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