He studied the DNA molecule to see if the child was related to the man.
It was the union of a small number of atoms of one kind with a small number of another kind to form a compound atom, or as we now say a "molecule."
The symbols of compounds become very concise, as the number of atoms of one kind in a molecule can be expressed by a sub-index.
By the entrance of amino or hydroxyl groups into the molecule dyestuffs are formed.
Thus the groupings J_C C - - C C - >N CH 3 and - C C C N exist in the molecule, and the alkaloid is to be represented as a-pyridyl-N-methyl-pyrollidine.
The cadmium molecule, as shown by determinations of the density of its vapour, is monatomic. The metal unites with the majority of the heavy metals to form alloys; some of these, the so-called fusible alloys, find a useful application from the fact that they possess a low melting-point.
The decomposition of the complex molecule of the sugar liberates a certain amount of energy, as can be seen from the study of the fermentation set tig by yeast, which is a process of this kind, in that it is intensified by the absence of oxygen.
(1) particles derived by limiting mechanical subdivision, the modern molecule, and (2) particles derived from the first class by chemical subdivision, i.e.
They assumed the atom to be the smallest part of matter which can exist in combination, and the molecule to be the smallest part which can enter into a chemical reaction.
The development of the atomic theory and its concomitants - the laws of chemical combination and the notion of atoms and equivalents - at the hands of Dalton and Berzelius, the extension to the modern theory of the atom and molecule, and to atomic and molecular weights by Avogadro, Ampere, Dumas, Laurent, Gerhardt, Cannizzaro and others, have been noted.
The structure of the molecule, which mainly followed investigations in organic compounds, Frankland's conception of valency, and finally the periodic law, have alsobeen shown in their chronological order.
The molecule of every compound must obviously contain at least two atoms, and generally the molecules of the elements are also polyatomic, the elements with monatomic molecules (at moderate temperatures) being mercury and the gases of the argon group. The laws of chemical combination are as follows: I.
The oxychloride, bromides, and other compounds were subsequently discovered; here we need only notice Moissan's preparation of the trifluoride and Thorpe's discovery of the pentafluoride, a compound of especial note, for it volatilizes unchanged, giving a vapour of normal density and so demonstrating the stability of a pentavalent phosphorus compound (the pentachloride and pentabromide dissociate into a molecule of the halogen element and phosphorus trichoride).
The binary conception of compounds held by Berzelius received apparent support from the observations of Gay Lussac, in 1815, on the vapour densities of alcohol and ether, which pointed to the conclusion that these substances consisted of one molecule of water and one and two of ethylene respectively; and from Pierre Jean Robiquet and Jean Jacques Colin, showing, in 1816, that ethyl chloride (hydrochloric ether) could be regarded as a compound of ethylene and hydrochloric acid.
By its aid the molecule is represented as a collection of atoms connected together by valencies in such a manner that the part played by each atom is represented;.
NH 2; secondary, R2: NH; and tertiary, R3: N; the oxamines, R 3 N :0, are closely related to the tertiary ammonias, which also unite with a molecule of alkyl iodide to form salts of quaternary ammonium bases, e.g.
The ringed structure of benzene, C 6 H 61 was first suggested in 1865 by August Kekule, who represented the molecule by six CH groups placed at the six angles of a regular hexagon, the sides of which denoted the valencies saturated by adjacent carbon atoms, the fourth valencies of each carbon atom being represented as saturated along alternate sides.
Although Kekule founded his famous benzene formula in 1865 on the assumptions that the six hydrogen atoms in benzene are equivalent and that the molecule is symmetrical, i.e.
This configuration is, according to Sachse, more stable than any other form; no oscillation is possible, the molecule being only able to move as a whole.
149, p. 20) established the symmetry of the naphthalene nucleus, and showed that whichever half of the molecule be oxidized the same phthalic acid results.
Bamberger opposed Claus' formula on the following grounds: - The molecule of naphthalene is symmetrical, since 2.7 dioxynaphthalene is readily esterified by methyl iodide and sulphuric acid to a dimethyl ether; and no more than two mono-substitution derivatives are known.
The molecule is aromatic but not benzenoid; however, by the reduction of one half of the molecule, the other assumes a benzenoid character.
If s-naphthylamine and 0-naphthol be reduced, tetrahydro products are obtained in which the aminoor oxy-bearing half of the molecule becomes aliphatic in character.
If a-naphthylamine and a-naphthol be reduced, the hydrogen atoms attach themselves to the non-substituted half of the molecule, and the compounds so obtained resemble aminodiethylbenzene, C 6 H 3 NH 2 (C 2 H 5) 21 and oxydiethylbenzene, C 6 H 3.
The formula has the advantage that it may be constructed from tetrahedral models of the carbon atom; but it involves the assumption that the molecule has within it a mechanism, equivalent in a measure to a system of railway points, which can readily close up and pass into that characteristic of benzene.
A more accurate expression (see Condensation Of Gases and Molecule) is (p+a/v 2) (v - b) =RT, in which a and b are quantities which depend on the composition of the gas, and vary from one gas to another.
For the complete determination of the chemical structure of any compound, three sets of data are necessary: (I) the empirical chemical composition of the molecule; (2) the constitution, i.e.