Molecule

“ Our definition of a molecule is purely dynamical. A molecule is that minute portion of a substance which moves about as a whole, so that its parts, if it has any, do not part company during the motion of agitation of the gas. The result of the kinetic theory, therefore, is to give us information about the relative masses of molecules considered as moving bodies. The consistency of this information with the deductions of chemists from the phenomena of combination, greatly strengthens the evidence in favour of the actual existence and motion of gaseous molecules. ”

“ I figure, as others do, a molecule as a group of atoms, held together by their mutual forces, but still capable of motion among themselves. The vapour of the nitrite of amyl is to be regarded as an assemblage of such molecules. The question now before us is this: In the act of absorption, is it the molecules that are effective, or is it their constituent atoms? Is the vis viva of the intercepted light-waves transferred to the molecule as a whole, or to its constituent parts? ”

“ The molecule of an element usually contains two atoms; that of a compound may have two, or it may have hundreds. For a given compound the number is always definite.
Chemism is the force that binds atoms together to form molecules. The sugar molecule contains atoms, forty-five in all, of three different elements: carbon, hydrogen, and oxygen. That of salt has two atoms: one of sodium, one of chlorine. Should we say "an atom of sugar"? Why? Of what is a mass of sugar made up? A molecule? A mass of carbon? A molecule? Did the chemical affinity of the acid break up masses or molecules? ”

“ We may even believe that there is in principle but one kind of atoms, and that it is the number of primitive atoms, essentially simple and homogeneous, their modes of arrangement, and their motions, which constitute the diversity of molecules; a molecule of gold, of iron, would not differ from a molecule of sulphur, of oxygen, of hydrogen, etc., except in the number, the disposition, and the motion of the primitive atoms which compose it: each molecule would be a system, a microcosm. ”

“ As a rule, two or more atoms first come together to form a larger particle, which we call a "molecule." Single atoms do not, as a rule, exist apart from other atoms; if a molecule is broken up, the individual atoms seek to unite with other atoms of another kind or amongst themselves. For example, three atoms of oxygen form what we call ozone; two atoms of hydrogen uniting with one atom of oxygen form water. It is molecules that form the mass of matter; a molecule, as it has been expressed, is a little building of which atoms are the bricks. ”

“ The molecule of a given substance, though often called an atom, is a system of primitive elements; and elements acting according to the Newtonian law can give rise to molecular systems which, at very small distances, will act according to any other law that may be indicated by molecular phenomena. This other law depends entirely on the number, kind, strength, and geometrical arrangement of the primitive elements which enter into the constitution of the molecule ”

“ Such an association of atoms is called a molecule. When a body is in the state of a gas or vapor, each molecule for the greater part of the time is unaffected by the other molecules in its neighborhood, and therefore behaves as if these were not present. ”

“ When he found that each of the known elements, such as copper or oxygen or carbon, consisted ultimately of atoms, all the atoms of any one element being alike, he laid the foundation on which the huge structure of modern chemistry has been raised. The chemist takes one or more atoms of one element, one or more of another, and may be of a third or fourth, and he puts them together into a compound which we call a molecule. ”

“ Any further division destroys the entity of the compound, and results in the decomposition of the salt into the atoms of its elements. Hence a simple molecule is the smallest portion of any chemical compound that is not susceptible of subdivision without destroying its entity, or, in other words, the smallest number of atoms that can cohere to form a compound constitute the molecule of that compound. An atom is designated as the ultimate particle of any elementary body, and is not susceptible of any further division within the range of human analysis. ”

“ Each molecule is formed by six atoms, that is by six little groups of electrons playing about six little nuclei. About each nucleus there is going on a game but some of the electrons are playing in the game about their own nucleus and at the same time taking some part in the game which is going on around one of the other nuclei. That’s why the groups or atoms stay together as a molecule. When the molecules wander out into the spaces between the water molecules something happens to this complicated game. ”

“ Such a molecule would have more atoms than the universe had suns.
Oversize molecules were the keys of life—the hormones, the activators, the carriers of heredity. What doors might not a supergiant molecule unlock? ”

“ The substance attains to a perfectly liquid state as soon as the energy of motion of the molecules is such that there is a constant rearrangement of position among them.
A molecule escaping from its original position in a body will usually fall into a new position in which it will be held in equilibrium by the forces from a new set of neighbouring molecules. ”

“ By chemical action, the structure of the molecule is changed, the atoms become grouped together in a different way, new relations manifest themselves among them, and the energy of the new molecule becomes different from that of the original one. ”

“ However large the masses changed by chemical action, that action is always on the individual molecule, the atoms of which are separated. If the molecule were an indivisible particle, no science of chemistry would be possible. The physicist finds the properties of masses of matter and resolves them into molecules, the chemist breaks up the molecule and from its atoms builds up other compounds. ”

“ The molecule is a material system, the parts of which are connected in some definite way, and from the fact that the bright lines of the emitted light have always the same wave-lengths, we learn that the vibrations corresponding to these lines are always executed in the same periodic time, and therefore the force tending to restore any part of the molecule to its position of equilibrium in the molecule must be proportional to its displacement relative to that position. ”

“ In the next closest arrangement, A, say, a molecule of any one layer touches only two molecules in each of the layers above and below it, so that one molecule is in contact with ten others altogether. ”

“ We will, then, imagine a molecule magnified to the size of a billiard ball, and the atomic triplet magnified to the size of three marbles, in the triangular position, within that molecule, at its centre; unless acted upon by electricity, when the molecule, the billiard ball, becomes oblate, and the three atoms are ranged in a line within, unless broken up by the mighty force of vibratory action. Nature never gives us a vacuum ”

“ In fact and in truth matter is made up, not of the large bulks we see, but of minute particles, called molecules, in the neighborhood, for the simplest element, hydrogen, of one fifty-millionth of an inch in diameter, and these minute molecules are in turn made up of very much smaller particles, atoms, two to a molecule in some elements, many more than two in others. ”

“ The atoms of carbon and hydrogen, oxygen, nitrogen, which enter into a complex molecule, do not lose the powers originally inherent in them, when they unite to form that molecule, the properties of which express those forces of the whole aggregation which are not neutralized and balanced by one another. Each atom has given up something, in order that the atomic society, or molecule, may subsist. ”

“ The loss of two alpha particles and the loss of a single beta particle in a molecule of lead, causes that molecule to become an isotopal molecule of gold, with an atomic number 79, and the atomic weight of 199. ”

“ When we have apparently satisfied the accepted atomic value of an element by allocating to it what we regard as the necessary complement of atoms of other bodies, it is frequently evident that the capacity for combination of the whole molecule is not satisfied. Many apparently saturated molecules have the power of combining with other equally saturated molecules. ”

“ As a result of the law of chemical action, that most elementary bodies exist in a condition where two atoms are joined together to form a molecule, it follows, that in most instances the molecular weights of the elements are double their atomic weight. ”

“ Though we have hitherto spoken of the essential attributes and properties of primitive beings, the doctrine we have expounded is also applicable to those of all substantial compounds. Thus the attributes and properties of a molecule of hydrogen, oxygen, or any other specific compound have the reason of their being in the essential principles of their respective compound, and nothing else is required to account for them, as is evident from the preceding explanations. ”

“ Now a liter of each gas has the same number of molecules, therefore the O molecule weighs 16 times the H molecule. The half-molecule of each has the same proportion, and the vapor density of O is 16. Atomic weight is obtained in a very different way. ”

“ Subjected to analysis, all these products yield identical substances in identical proportions, that is, for each molecule of essence, ten atoms of carbon, and sixteen atoms of oxygen, as denoted by their common formula, C10O16. We see how these facts as to isomery prove that the qualities of bodies depend far more on the arrangement and the inner movements of their minute particles, never to be reached by our search, than on the nature of their matter itself ”

“ Is there, in the inorganic world, a happy concourse of atoms that become chained together through the action of the sun's rays and other natural forces, so that a molecule of living matter is constructed in nature's laboratory without contact or close association with living substance? ”

“ It is not in the atom itself, unless it be in the size, as may not be improbable. The atoms combine in different numbers to make differently shaped molecules, and it is from this difference in the shape of the molecule that we get the difference between gold and silver, copper and tin, or oxygen and hydrogen. ”

“ When a system is composed of a mixture of different kinds of molecules, the fact that h is the same for each constituent [cf. formulae. (5) and (6) ] shows that in the normal state the different substances are all at the same temperature. For instance, if the system is composed of a gas and a solid boundary, some of the terms in expression (2) may be supposed to represent the kinetic energy of the molecules of the boundary, so that equations (7) show that in the normal state the gas has the same temperature as the boundary. ”