Carbon atom

“ Its affinities seem satisfied when it has two bonds. But, on the other hand, the atom of nitrogen is able to hold three atoms of hydrogen, and does so in the molecule of ammonium (NH3) ; while the carbon atom can hold four atoms of hydrogen or two atoms of oxygen.
Evidently, then, one atom is not always equivalent to another atom of a different kind in combining powers. ”

“ For the molecule of tartaric acid—in common with the molecules of all carbon compounds the solutions of which, or which themselves in the liquid state, rotate the plane of polarisation—possesses an asymmetric carbon atom, an atom of carbon which is linked by its four valency attachments to four different kinds of atoms or radicle groups ”

“ Two atoms of tetravalent carbon, each linked by one combining unit, will experience four oscillations, striking each other and three other atoms in the unit of time, while the monovalent hydrogen atom makes only one oscillation. The doubly linked carbon will collide with its neighbouring atom twice, and also with two other atoms within the same period. The assumption that the carbon atom has a more rapid motion than the hydrogen atom is, however, not warranted by the kinetic theory. ”

“ In this case, each atom of carbon will unite with two of oxygen, and the result will be something quite different from either. Yet under ordinary circumstances carbon, or its representative, coal, will remain unchanged in the presence of oxygen, or of atmospheric air containing oxygen. There will be no tendency to combine together, because although the particles of the oxygen would appear to be in immediate contact with those of the carbon, yet the nearness is not sufficient to permit of chemical affinity acting with advantage. ”

“ The free or residual affinity possessed by each carbon atom asserts itself under the various conditions which can be brought into existence by these pulsations, with the effect that the several linkings produced must involve always a pair of carbon atoms and then in turn during the second stage of the pulsation must suffer a break and consequently give rise to some particular one of the seven possible phases, with its characteristic absorption band of course depending upon the carbon atoms in question. ”

“ These bridges are distinguished by numbers, denoting the number of carbon atoms contained in them, the direct union of the two tertiary carbon atoms being designated as 0; if one carbon atom intervenes, then the number 1 is used, and so on. ”

“ The potential energies of the atoms of matter, in their free condition, are almost beyond human comprehension. Thus, heat a pound of charcoal to the point of incandescence. The vibratory motion of the atoms of carbon will then have reached an amazing velocity; oxygen rushes in to form new compounds; the oxygen-atom, by its impact upon the coal, has its motion of translation converted into vibratory motion, which immediately appears as heat. The clash of these atoms makes up the sum total of the energies of the combustion. ”

“ The process consists in using solar energy to fix the carbon of carbonic acid, and thereby to store this energy as we should store that of a water-carrier by employing him to fill an elevated reservoir: the water, once brought up, can set in motion a mill or a turbine, as we will and when we will. Each atom of carbon fixed represents something like the elevation of the weight of water, or like the stretching of an elastic thread uniting the carbon to the oxygen in the carbonic acid. ”

“ In any gaseous hydrocarbon, again, the carbon exists in the gaseous state, and when 1 atom of the hypothetical gaseous carbon combines with 1 atom of oxygen to produce 1 molecule of carbon monoxide, 68.2 large calories are evolved. Thus while solid amorphous carbon emits more heat than a chemically equivalent quantity of hydrogen provided it is enabled to combine with its higher proportion of oxygen, it emits less if only carbon monoxide is formed ”

“ If in this carbon the three processes of the planet, namely, the formative or its special, the chemicalizing or fluidizing, and the electrifying or oxydizing, process, concentrate themselves, and are present with all185 their energy in every atom of the organic body; so must the mass of carbon be at the same time solid, fluid, and aerial, oxydizable in every spot, and thus also soft. Now a carbon mixed identically with water and air is Mucus. ”

“ It is not acted on at ordinary temperatures by most reagents, but at a higher temperature it combines directly with many of the elements, forming compounds called carbides. When heated in the presence of sufficient oxygen it burns, forming carbon dioxide.
Uses of carbon. The chief use of amorphous carbon is for fuel to furnish heat and power for all the uses of civilization. An enormous quantity of carbon in the form of the purer coals, coke, and charcoal is used as a reducing agent in the manufacture of the various metals, especially in the metallurgy of iron. ”

“ Oxygen and nitrogen are free as air, and as we have seen in the second chapter, their direct combination by the electric spark is possible. Hydrogen is free in the form of water but expensive to extricate by means of the electric current. But we need more carbon than anything else and where shall we get that? Bits of crystallized carbon can be picked up in South Africa and elsewhere, but those who can afford to buy them prefer to wear them rather than use them in making synthetic food. Graphite is rare and hard to melt. We must then have recourse to the compounds of carbon. ”

“ It naturally follows that if along with the requisite temperature sufficient pressure is applied, liquefaction of carbon will take place, when on cooling it will crystallise. But carbon at high temperatures is a most energetic chemical agent, and if it can get hold of oxygen from the atmosphere or any compound containing it, it will oxidise and fly off in the form of carbonic acid. Heat and pressure therefore are of no avail unless the carbon can be kept inert. ”

“ When we have a perfectly cleansed and purified piece of carbon, there is no ash left. The carbon burns as a solid dense body, that heat alone cannot change as to its solidity, and yet it passes away into vapour that never condenses into solid or liquid under ordinary circumstances; and what is more curious still, is the fact that the oxygen does not change in its bulk by the solution of the carbon in it. Just as the bulk is at first, so it is at last, only it has become carbonic acid. ”

“ If you heat coal or wood away from the air, some gas comes away, and leaves behind coke from coal, and charcoal from wood; both carbon, though not pure. Heat carbon as much as you will in a close vessel, and it does not change in the least; but let the air get to it, and then it burns and flies off in carbonic acid gas. This makes carbon so convenient for fuel. But it is ornamental as well as useful, uncle The diamond is nothing else than carbon. ”

“ The positive carbon is pressed steadily against the negative by the action of a weight. The increased resistance to the passage of the current, at the sharp point of the positive carbon, generates sufficient heat to produce a powerful light. The light resembles a steadily radiant star, but 'with all its softness and purity of tint, it is so intense, that adjacent gas-flames are thrown on the wall as transparent shadows.' The light will last for fifteen hours without attention, the positive carbon rod being used in lengths of three feet. The carbon block hardly undergoes any change. ”

“ Now let us try to make some carbonic acid.—Will you, Emily, decant some oxygen gas from this large jar into the receiver in which we are to 293 burn the carbon; and I shall introduce this small piece of charcoal, with a little lighted tinder, which will be necessary to give the first impulse to the combustion.
EMILY.
I cannot conceive how so small a piece of tinder, and that but just lighted, can raise the temperature of the carbon sufficiently to set fire to it; for it can produce scarcely any sensible heat, and it hardly touches the carbon. ”

“ We have already seen that carbon follows quite a different law from the other concrete elements, in the fact that its electrical resistance diminishes as the temperature rises; it also differs widely from the other solid elements in its atomic heat, which has a value much less than one-half the mean constant, which is 6.4. ”

“ Thus, carbon has four poles, or is quadrivalent, and its atoms possess the power of combining among themselves to an almost indefinite extent and forming groups of great stability. Thus, carbon radicals may be formed in very great number, each affording a nucleus upon which compound radicals may be built up, so that carbon has been aptly called the skeleton of almost all the varied compounds of the more complex forms of inorganic matter as well as the principal foundation of organic life. ”

“ The reason why air is a mixture and not a compound is an interesting one, and brings us to our next point. In order to form a compound, two different kinds of atoms must have an attraction for each other. There is no attraction between oxygen and nitrogen; but there is great attraction between oxygen and carbon, and when they get a chance they rush together like long separated lovers. Anthracite coal is almost pure carbon. So is charcoal. Soft coal consists of carbon with which various other things are united, one of them being hydrogen. ”

“ Indeed, you have yourselves frequently tried a very pretty experiment, by which you may see the carbon in wood. If you take a piece of wood, and partly burn it, and then blow it out, you have carbon left. There are things that do not shew carbon in this way. A candle does not shew it, but it contains carbon. Here also is a jar of coal-gas, which produces carbonic acid abundantly. You do not see the carbon, but we can soon shew it to you. I will light it, and as long as there is any gas in this cylinder it will go on burning. You see no carbon, but you see a flame ”

“ Elementary carbon ought to be gaseous at the ordinary temperature, and the various kinds of carbon which occur in nature are in reality polymerized products of the true element carbon. Spectrum analysis is thought to confirm this view; and it is supposed the second spectrum seen in a Geissler tube belongs to gaseous carbon. ”

“ The case of carbon-14 is an example of a permanent man-made modification of the environment. From the early ages of the earth, carbon-14 has been created in the upper atmosphere by the transmutation of nitrogen in cosmic-ray reactions. Carbon itself is an almost universal component of living matter, and the ratio between stable carbon and radioactive carbon is believed to have been unchanged for thousands of years. ”

“ If we take the same unit for the measurement of light, it must further be specified that the combustion of the carbon must be so effected as to produce carbonic acid and not carbonic oxide, and that it must take place in atmospheric air, and not in pure oxygen, or any other medium. That being borne in mind, it is probable that the combustion of a definite quantity of carbon would prove a better measure of light than any that has yet been tried. ”

“ In the mean time, I suppose, we must be content with making carbon so brilliant as it is in the flame of a candle. Well; now you see that a candle-flame is vapor burning, and the vapor, in burning, turns into water and carbonic acid gas. The oxygen of both the carbonic acid gas and the water comes from the air, and the hydrogen and carbon together are the vapor. They are distilled out of the melted wax by the heat. But, you know, carbon alone can’t be distilled by any heat. ”

“ Carbon is a solid element; it is not known in the [47] free state, either as a liquid or as a gas. Carbon is remarkable as existing in three distinct forms, which in outward appearance or physical properties have nothing in common, whilst their chemical relations are identical. These three allotropic forms of carbon are (1) diamond, (2) graphite or plumbago, (3) charcoal. These substances differ in hardness, color, specific gravity, etc., but they each yield on combustion in the air or oxygen the same weight of the same substance, carbonic acid or carbon dioxide. ”

“ Judging from the fact that carbon forms a number of gaseous bodies (carbonic oxide, carbonic anhydride, methane, ethylene, acetylene, &c.) and volatile substances (for example, many hydrocarbons and their most simple derivatives) , and considering that the atomic weight of carbon, C = 12, approaches that of nitrogen, N = 14, and that of oxygen, O = 16, and that the compounds CO (carbonic oxide) and N2C2 (cyanogen) are gases, it may be argued that if carbon formed the molecule C2, like N2 and O2, it would be a gas. ”

“ The carbonic acid gas produced simply by the breathing of the great human family amounts every year to about 160,000,000,000 cubic meters, which represents 86,270,000,000 kilograms of burnt carbon. Piled up, this carbon would form a mountain one league round at its base and between four hundred and five hundred meters high. So much carbon is required by man to maintain his natural heat. All of us together eat this mountain of carbon in our food and in the course of the year dissipate it all in the air, a breathful at a time ”

“ The first difficulty arose from the waste of the carbons, which are dissipated in part by ordinary combustion, and in part by the electric transfer of matter from the one carbon to the other. To keep the carbons at the proper distance asunder regulators were devised, the earliest, I believe, by Staite, and the most successful by Duboscq, Foucault, and Serrin, who have been succeeded by Holmes, Siemens, Browning, Carré, Gramme, Lontin, and others. ”

“ Many organic and some inorganic bodies hold carbon so loosely combined that it can be separated out under the influence of chemical action, heat or electricity, but invariably the carbon assumes the black amorphous form. The other method is to try to fuse the carbon by fierce heat, when from analogy it is argued that on cooling it will solidify to a clear limpid crystal. ”