Vapours sentence example
The vapours pass between the inner and outer tubes.
A dissolved in B and B dissolved in A, since both of these solutions emit vapours of the same composition (this follows since the same vapour must be in equilibrium with both solutions, for if it were not so a cyclic system contradicting the second law of thermodynamics would be realizable).
A more general designation is "pyrogenic processes," which also includes such operations as leading vapours through red-hot tubes and condensing the products.
Sidney Young has suggested conducting the operation in a current of carbon dioxide which sweeps out the vapours as they are evolved, and also heating in a vapour bath, e.g.
In its simplest form the apparatus consists of a straight tube, made of glass, porcelain or iron according to the temperature required and the nature of the reacting substances, heated in an ordinary combustion furnace, the mixture entering at one end and the vapours being condensed at the other.Advertisement
Apparatus can also be constructed in which the unchanged vapours are continually circulated through the tube.
It is invariably provided with an opening to carry off the vapours produced.
For example, in the less modern methods for manufacturing nitric acid the vapours were conducted directly into double-necked bottles (bombonnes) immersed in water.
By an arrangement of diaphragms in the lower trough the vapours are circulated through the system.
He also carried out many experiments in magneto-optics, and succeeded in showing, what Faraday had failed to detect, the rotation under the influence of magnetic force of the plane of polarization in certain gases and vapours.Advertisement
Laplace is due the theoretical proof that this function is independent of temperature and pressure, and apparent experimental confirmation was provided by Biot and Arago's, and by Dulong's observations on gases and vapours.
P. Dale; the more simple formula (n - i)/d, which remained constant for gases and vapours, but exhibited slight discrepancies when liquids were examined over a wide range of temperature, being adopted.
Window glass exposed to alkaline vapours often shows a thin iridescent surface film which is supposed to be due to crystallization; the same change is found in pieces of Roman glass which have been dug out of the ruins of Pompeii.
A stick of green wood is forced into it, and the vapours and gases set free expose new surfaces to the air, which at this temperature has only a mildly oxidizing effect.
These liquids, when exposed to higher temperatures, some sooner than others, pass into vapours.Advertisement
What these vapours are like is not known in many cases, since, as a rule, they can be produced only at very high temperatures, precluding the use of transparent vessels.
Practically any vessel may serve as a receiver - test tube, flask, beaker, &c. If noxious vapours come over, it is necessary to have an air-tight connexion between the condenser and receiver, and to pro vide the latter with an outlet tube leading to an absorption column or other contrivance in which the vapours are taken up. If the substances operated upon decompose when heated in air, as, for example, the zinc alkyls which inflame, the air within the apparatus is replaced by some inert gas, e.g.
One of the earliest red-hot tube syntheses of importance was the formation of naphthalene from a mixture of alcohol and ether vapours.
As an auxiliary to air cooling the stack may be cooled by a slow stream of water trickling down the outside of the pipes, or, in certain cases, cold water may be injected into the condenser in the form of a spray, w here it meets the ascending vapours.
Dephlegmation of the vapours arising from such mixtures as coaltar fractions, petroleum and the "wash" of the spirit industry, is very important, and many types of apparatus are employed in order to effect a separation of the vapours.Advertisement
The vapours rising from the still traverse a tall vertical column, and are then conveyed through a series of bulbs placed in a bath kept at the boiling-point of the most volatile constituent.
The more volatile vapours pass over to the condensing plant, while the less volatile ones condense in the bulbs and are returned to the column at varying heights by means of connecting tubes.
It consists of a vertical column divided into a number of sections by horizontal plates, which are perforated so that the ascending vapours have to traverse a layer of liquid.
The water, moreover, till it is saturated with gases, readily absorbs noxious vapours to which it may be exposed.
Others regard him as a wind-hero, who disperses the pestilential vapours of the fens.Advertisement
For example, if vapours of the volatile metals cadmium, zinc and magnesium are allowed to act on platinum or palladium, alloys are produced.
An ideal gas is a substance possessing very simple thermodynamic properties to which actual gases and vapours appear to approximate indefinitely at low pressures and high temperatures.
The simplest assumption which suffices to express the small deviations of gases and vapours from the ideal state at moderate pressures is that the coefficient a in the expression for the capillary pressure varies inversely as some power of the absolute temperature.
As an example of one of the few cases where a complete solution is possible, we may take the comparatively simple case equation (17), already considered, which is approximately true for the majority of vapours at moderate pressures.
They are provided with lids, made either of lead or of wood lined with lead, which have openings to serve for the introduction of the alloy and acid, and a vent tube to lead off the vapours evolved during the operation.
In addition to nitrogen and oxygen, there are a number of other gases and vapours generally present in the atmosphere.
The commercial salt is known as salvolatile or salt of hartshorn and was formerly obtained by the dry distillation of nitrogenous organic matter such as hair, horn, decomposed urine, &c., but is now obtained by heating a mixture of sal-ammoniac, or ammonium sulphate and chalk, to redness in iron retorts, the vapours being condensed in leaden receivers.
The graphite veins in the older crystalline rocks are probably akin to metalliferous veins and the material derived from deep-seated sources; the decomposition of metallic carbides by water and the reduction of hydrocarbon vapours have been suggested as possible modes of origin.
Chromic acid and its salts, the chromates and bichromates, can be detected by the violet coloration which they give on addition of hydrogen peroxide to their dilute acid solution, or by the fact that on distillation with concentrated sulphuric acid and an alkaline chloride, the red vapours of chromium oxychloride are produced.
The sesquioxide, Cr 2 0 3, occurs native, and can be artificially obtained in several different ways, e.g., by igniting the corresponding hydroxide, or chromium trioxide, or ammonium bichromate, or by passing the vapours of chromium oxychloride through a red-hot tube, or by ignition of mercurous chromate.
It is evident that by the use of a spectroheliograph of sufficiently high dispersion, photographs may be taken of vapours in the sun represented by lines narrower than those of calcium and hydrogen.
When there is appreciable absorption as in the case of the vapours of chlorine, bromine, iodine, sulphur, selenium and arsenic, luminosity begins at a red heat.
Such spectra seem to be characteristic of complex molecular structure, as they appear when compounds are raised to incandescence without decomposition, or when we examine the absorption spectra of vapours such as iodine and bromine and other cases where we know that the molecule consists of more than one atom.
While some of the phenomena seem to indicate that the projection of metallic vapours into the centre of the spark is a process of molecular diffusion independent of the mechanism of the discharge, the different velocities obtained with bismuth, and the probability that the vibrating systems are not electrically neutral, seem to indicate that the projected metallic particles are electrified and play some part in the discharge.
Wiedemann and Schmidt' that the vapours of sodium and potassium are fluorescent, important as it was from an experimental point of view, caused no surprise.
The soffioni contain a small quantity of boric acid (usually less than o 1%), together with a certain amount of ammoniacal vapours.
Tyndall's investigations of the transparency and opacity of gases and vapours for radiant heat, which occupied him during many years (1859-1871), are frequently considered his chief scientific work.
He made brilliant experiments elucidating the blue of the sky, and discovered the precipitation of organic vapours by means of light.
The corresponding phenomenon in the case of vapours is well known.
On the large scale it is obtained by distilling Chile saltpetre with concentrated sulphuric acid in horizontal cast iron stills, the vapours being condensed in a series of stoneware Woulfe's bottles.
As an alternative method the nitrate may be warmed with some fragments of copper and sulphuric acid which has been diluted with its own volume of water, when characteristic brown vapours will be seen.
This purified oxide, mixed with sodium chloride and coal tar, was carbonized at a red heat, and ignited in a current of dry chlorine as long as vapours of the double chloride were given off, these being condensed in suitable chambers.
The process exhibited several disadvantages, the electrolyte had to be kept constant in composition lest either fluorine vapours should be evolved or sodium thrown down, and the raw materials had accordingly to be prepared in a pure state.
Great care should be taken in using dimethyl and diethyl sulphates, as the respiratory organs are affected by the vapours, leading to severe attacks of pneumonia.
These vessels, as well as all others which are used in the process, are not open to the air, but communicate with it through washers in which fresh salt solution is employed for retaining any escaping vapours of ammonia.
An application of these results to solar physics in conjunction with Sir Norman Lockyer led to the view that at least the external layers of the sun cannot consist of matter in the liquid or solid forms, but must be composed of gases or vapours.
In The Case Of Solids And Liquids Under Ordinary Conditions Of Pressure, The External Work Of Expansion Is So Small That It May Generally Be Neglected; But With Gases Or Vapours, Or With Liquids Near The Critical Point, The External Work Becomes So Large That It Is Essential To Specify The Conditions Under Which The Specific Heat Is Measured.
They Also Indicate That It Is Much Larger, And Increases Considerably With Rise Of Temperature, In The Case Of More Condensible Vapours, Such As C1 2J Br 2, Or More Complicated Molecules, Such As Co 2, N 2 0, Nh 3, C 2 H 4.
This Would Account For An Increase Of S, And A Diminution Of The Ratio S/S, With Rise Of Temperature Which Apparently Occurs In Many Vapours.
It was applied in the most perfect manner by Regnault to determine the latent heats of steam and several other vapours at high pressures.
This was known as Watt's law, and was sometines extended to other vapours.
In order to correct this equation for the deviations of the vapour from the ideal state at higher temperatures and pressures, the simplest method is to assume a modified equation of the Joule-Thomson type (Thermodynamics, equation (17)), which has been shown to represent satisfactorily the behaviour of other gases and vapours at moderate pressures.
Many attempts have been made to construct formulae representing the deviations of vapours from the ideal state up to the critical point.
The specific volumes of superheated vapours may, however, (19) be measured with a satisfactory degree of approximation.
It is found by these methods that the behaviour of superheated vapours closely resembles that of noncondensible gases, and it is a fair inference that similar behaviour would be observed up to the saturation-point if surface condensation could be avoided.
A similar method of calculation might be applied to deduce the thermodynamical properties of other vapours, but the required experimental data are in most cases very imperfect or even entirely wanting.
It is also formed in the pancreatic fermentation of albumen, and, in small quantities, by passing the vapours of monoand dialkylanilines through a red-hot tube.
His method consisted in using magnesia instead of lime for the recovery of the ammonia (which occurs in the form of ammonium chloride in the ammonia-soda process), and then by evaporating the magnesium chloride solution and heating the residue in steam, to condense the acid vapours and so obtain hydrochloric acid.
By boiling this varnish with dilute nitric acid vapours of acrolein are given off, and the substance gradually becomes a solid non-adhesive mass the same as the ultimate oxidation product of both raw and boiled oil.
The dry way is best; the wet way is only employed when fuel is very dear, or when it is absolutely necessary that no noxious vapours should escape into the atmosphere.
In Baluchistan these volcanoes appear to be extinct; though the Koh-i-Tafdan, beyond the Persian frontier, still emits vapours at frequent intervals.
This is not strictly the case, however, for such gases and vapours as exhibit well-defined bands of absorption in the spectrum, as these bands are altered in character by compression.
It is also remarkable that many gases and vapours, e.g.
Ordinary sulphuric acid, H 2 SO 4, may be prepared by dissolving sulphur trioxide in water, a reaction accompanied by a great evolution of heat; by the gradual oxidation of an aqueous solution of sulphur dioxide, a fact which probably explains the frequent occurrence of sulphuric acid in the natural waters rising in volcanic districts; or by deflagrating a mixture of sulphur and nitre in large glass bells or jars, absorbing the vapours in water and concentrating the solution.
As this reaction of its own accord takes place only to a very small extent, an" oxygen carrier "is always introduced in the shape of the vapours of nitric acid or the lower oxides of nitrogen.
The gases now pass on to the lead chambers, described above, where they meet with more nitrous vapours, and with steam, or with water, converted into a fine dust or spray.
This gas is now passed through the Gay-Lussac tower, which somewhat resembles the Glover tower, but is usually filled with coke, over which sulphuric acid of about 80% H2504 trickles down in sufficient quantity to retain the nitrous vapours.
A third consideration is the condensation of the vapours formed in the concentrating process; the further the concentration proceeds the more sulphuric acid they contain.
There is very little doubt that the general course of the decompositions follows these iines; but any such simple explanation of the actions taking place is rendered impossible by the fact that, instead of the breaking-down of the hydrocarbons being completed in the coal, and only secondary reactions taking place in the retort, in practice the hydrocarbons to a great extent leave the coal as the vapours of condensible hydrocarbons, and the breaking down of these to such simple gaseous compounds as ethylene is proceeding in the retort at the same time as the breaking up of the ethylene already formed into acetylene and methane, and the polymerization of the former into higher compounds.
Coal gas, being a mixture of gases and vapours of liquids having very varying boiling points, must necessarily undergo physical changes when the temperature is lowered Vapours of liquids of high boiling point will be condensed more quickly than those having lower boiling points, but condensation of each vapour will take place in a definite ratio with the decrease of temperature, the rate being dependent upon the boiling point of the liquid from which it is formed.
The solubility of naphthalene by various oils has led some engineers to put in naphthalene washers, in which gas is brought into contact with a heavy tar oil or certain fractions distilled from it, the latter being previously mixed with some volatile hydrocarbon to replace in the gas those illuminating vapours which the oil dissolves out; and by fractional distillation of the washing oil the naphthalene and volatile hydrocarbons are afterwards recovered.
A partly successful attempt to make use of certain portions of the liquid products of distillation of coal before condensation by the second method was the Dinsmore process, in which the coal gas and vapours which, if allowed to cool, would form tar, were made to pass through a heated chamber, and a certain proportion of otherwise condensible hydrocarbons was thus converted into permanent gases.
In carburetting such a gas by injecting mineral oil into the retort, many of the products of the decomposition of the oil being vapours, it would be wasteful to do so for the first two hours, as a rich gas is being given off which has not the power of carrying in suspension a much larger quantity of hydrocarbon vapours without being supersaturated with them.
Undoubtedly the best process which has been proposed for the production of oil gas to be used in the enrichment of coal gas is the" Young "or" Peebles "process, which depends on the principle of washing the oil gas retorted at a moderate temperature by means of oil which is afterwards to undergo decomposition, because in this way it is freed from all condensible vapours, and only permanent gases are allowed to escape to the purifiers.
Enriching the gas by vapours and permanent gases obtained by decomposing the tar formed at the same time as the gas.
The carburetting of low-power gas by impregnating it with the vapours of volatile hydrocarbons.
Mixing the coal gas with water gas, which has been highly carburetted by passing it with the vapours of various hydrocarbons through superheaters in order to give permanency to the hydrocarbon gases.
Its purport is that glowing vapours similarly circumstanced absorb the identical radiations which they emit.
Further, certain cubic crystals, such as sodium chlorate and bromate, and also some liquids and even vapours, rotate the plane of polarization of the light that traverses them, whatever may be the direction of the stream.
The solution of the extracted oil or fat is then transferred to a steam-heated still, where the solvent is driven off and recovered by condensing the vapours in a cooling coil, to be used again.
On heating the solvent with steam through a coil or jacket, the vapours rise through and around the meal.
The distillation is generally performed in a still with an inlet for steam and an outlet to carry the vapours laden with essential oils into a condenser, where the water and oil vapours are condensed.
The vapours thus generated are drawn into the pump, compressed, and discharged into the condenser at the temperature T2, which is somewhat above that of the cooling water.
The principle of the absorption process is chemical or physical rather than mechanical; it depends on the fact that many Absorp- vapours of low boiling-point are readily absorbed in water, and can be separated again by the application of heat.
In 1867 Rees Reece, taking advantage of the fact that two vapours of different boiling-points, when mixed, can be separated by means of fractional condensation, brought out an absorption machine in which the distillate was very nearly anhydrous.
These clays are produced by the decomposition of the granite by acid vapours, which are discharged after the igneous rock has solidified ("fumarole or pneumatolytic action").
The fifth type of wave detector depends upon the peculiar property of rarefied gases or vapours which under some circumstances possess a unilateral conductivity.
From 1861 onwards he devoted much attention to the question of diathermancy in gases and vapours, especially to the behaviour in this respect of dry and moist air, and to the thermal effects produced by the condensation of moisture on solid surfaces.
A coordination of the results obtained on the distillation of mixtures of this nature with the introduction of certain theoretical considerations led to the formation of three groups distinguished by the relative solubilities of the vapours in the liquid components.
It may conveniently be called the Total Heat, by a slight extension of the meaning of a term which has been for a long time in use as applied to vapours (see Vaporization).
Discussing the theory of capillary attractions, Young' found that at a rough estimate " the extent of the cohesive force must be limited to about the 250-millionth of an inch " (=10 8 cms.), and then argues that " within similar limits of uncertainty we may obtain something like a conjectural estimate of the mutual distance of the particles of vapours, and even of the actual magnitude of the elementary atoms of liquids..
These are of pneumatolytic origin (see Pneumatolysis), and have been formed by the action of vapours emanating from cooling bodies of basic eruptive rock.
Richard Head in his Life and Death of Mother Shipton (1684) says, "the body was of indifferent height, her head was long, with sharp fiery eyes, her nose of an incredible and unproportionate length, having many crooks and turnings, adorned with many strange pimples of divers colours, as red, blue and dirt, which like vapours of brimstone gave such a lustre to her affrighted spectators in the dead time of the night, that one of them confessed several times in my hearing that her nurse needed no other light to assist her in her duties" Allowing for the absurdity of this account, it certainly seems (if any reliance is to be placed on the so-called authorities) that the child was phenomenally plain and deformed.
The agreement of the values of H with those of Griffiths and Dieterici at low temperatures, and of the values of p with those of Regnault over the whole range, are a confirmation of the accuracy of the foregoing theory, and show that the behaviour of a vapour like steam may be represented by a series of thermodynamically consistent formulae, on the assumption that the limiting value of the specific heat is constant, and that the isothermals are generally similar in form to those of other gases and vapours at moderate pressures.
Plouton, also associated with Proserpine, the great mother-goddess, was patron of the chasms with mephitic vapours in the valley of the Maeander (see Frazer, Adonis, 170 sqq.).
Hence above the spots there are vapours of temperature low enough to give the banded spectra of this refractory metal, while only line spectra of sodium, iron and others fusible at more moderate temperatures are found (see also Spect Roheliogra Ph).
Most of the metallic vapours that produce this lie too close to the photosphere for the separation to be made except during eclipses, when a flash spectrum of bright lines shines out for, say, five seconds after the continuous spectrum has disappeared, and again before it reappears (see Eclipse).
When the necessary temperature of the fuel and superheater has been reached, the air blast is cut off, and steam is blown through the generator, forming water gas, which meets the enriching oil at the top of the first superheater, called the carburettor, and carries the vapours with it through the main superheaters, where the fixing of the hydrocarbons takes place.
The mists, due to the great heat and excessive evaporation, and the noxious miasmata, especially of the southern region, were exaggerated into the noisome vapours that the "black and stinking" waters ever exhaled.
In light Kundt's name is widely known for his inquiries in anomalous dispersion, not only in liquids and vapours, but even in metals, which he obtained in very thin films by means of a laborious process of electrolytic deposition upon platinized glass.
The stills were formerly completely bricked in, so that the vapours should be kept fully heated until they escaped to the condenser, but since the introduction of the " cracking process," the upper part has usually been left exposed to the air.
In the American petroleum refineries it is found that sufficient cracking can be produced by slow distillation in stills of which the upper part is sufficiently cool to allow of the condensation of the vapours of the less volatile hydrocarbons, the condensed liquid thus falling back into the heated body of oil.
The steam operates by carrying the vapours away to the condenser as fast as they are generated, the injury to the products resulting from their remaining in contact with the highly-heated surface of the still being thus prevented.
The vapours from the still pass through a condenser into a receiver, which is in communication with the exhauster.
Owing to the high barrier which shuts off almost all Syria from the sea, and precipitates vapours mainly on the western slope, little of the land is highly productive without irrigation, except the narrow littoral strip which was the ancient Phoenicia, and the small deltas, such as that of Latakia (Laodicea).
Fischer, Ber., 1884, 17, p. 102); by passing the vapours of orthoaminodiphenylmethane over heated litharge (0.
The vapours pass through the inner tube, and the cold water enters at the end farthest from the distilling flask.
In the Linnemann column the condensed vapours temporarily collect on platinum gauzes (a) placed at the constrictions of a bulbed tube.
Vapours are emitted which deposit sulphur and alum, and some mining is carried on.