Solutions Sentence Examples
The calorimeter used for solutions is usually cylindrical, and made of glass or a metal which is not, attacked by the reacting substances.
As to the detergent action of a soap, Berzelius held that it was due to the free alkali liberated with water; but it is difficult to see why a solution which has just thrown off most of its fatty acids should be disposed to take up even a glyceride, and, moreover, on this theory, weak cold solutions, in which the hydrolysis is considerable, should be the best cleansers, whilst experience points to the use of hot concentrated solutions.
The pentathionates give a brown colour on the addition of ammoniacal solutions of silver nitrate and ultimately a black precipitate.
In 1887 a committee reported that the coupler question was the " knottiest mechanical problem that had ever been presented to the railroad," and over 4000 attempted solutions were on record in the United States Patent Office.
Hess now observed that in the process of mixing such neutral solutions no thermal effect was produced - that is, neutral salts in aqueous solution could apparently interchange their radicals without evolution or absorption of heat.Advertisement
In discussing nutrition, not only is there little agreement on the nature of the solutions, there is often disagreement on the nature of the problems.
It sublimes in thin plates of a dark colour and metallic lustre, and is soluble in solutions of the caustic alkalis.
As a very great number of important chemical actions take place on mixing solutions, the method for such cases has been thoroughly studied.
Known quantities of the solutions are taken, and the temperature of each is accurately measured before mixing, the solutions having been allowed as far as possible to adjust themselves to the same temperature.
Its property of absorbing large proportions of water, up to 80%, and yet present the appearance of a hard solid body, makes the material a basis for the hydrated soaps, smooth and marbled, in which water, sulphate of soda, and other alkaline solutions, soluble silicates, fuller's earth, starch, &c. play an important and bulky part.Advertisement
It possesses all the characteristic properties of an aldehyde; being readily oxidized to benzoic acid; reducing solutions of silver salts; forming addition products with hydrogen, hydrocyanic acid and sodium bisulphite; and giving an oxime and a hydrazone.
When the ancients could not find these solutions, it was not for a lack of intelligence but for a lack of technology.
However, I don't think finding these solutions means an end to all our troubles.
A modern branch of mathematics having achieved the art of dealing with the infinitely small can now yield solutions in other more complex problems of motion which used to appear insoluble.
It reduces ammoniacal silver solutions.Advertisement
In 1826 he described the prismatically-coloured films of metal, known as Nobili's' rings, deposited electrolytically from solutions of lead and other salts when the anode is a polished iron plate and the cathode is a fine wire placed vertically above it.
Solutions of yttria salts in their behaviour to reagents are not unlike those of zirconia.
The derrick crane introduces a problem for which many solutions have been sought, that of preventing the load from being lifted or lowered when the jib is pivoted up or down to alter the radius.
Davy on the decomposition of the solutions of salts by the voltaic current were turned to account in the water voltameter telegraph of Sdmmering and the modification of it proposed by Schweigger, and in a similar method proposed by Coxe, in which a solution of salts was substituted for water.
Cadmium sulphide, CdS, occurs naturally as greenockite (q.v.), and can be artificially prepared by passing sulphuretted hydrogen through acid solutions of soluble cadmium salts, when it is precipitated as a pale yellow amorphous solid.Advertisement
Normal cadmium carbonates are unknown, a white precipitate of variable composition being obtained on the addition of solutions of the alkaline carbonates to soluble cadmium salts.
Cadmium salts can be recognized by the brown incrustation which is formed when they are heated on charcoal in the oxidizing flame of the blowpipe; and also by the yellow precipitate formed when sulphuretted hydrogen is passed though their acidified solutions.
Even in that book Hume is able to play with sceptical solutions.
The perchloride of mercury is another very powerful antiseptic used in solutions of strength I in 2000, I in 1000 and 1 in 500.
The molybdates may be recognized by the fact that they give a white precipitate on the addition of hydrochloric or nitric acids to their solutions, and that with reducing agents (zinc and sulphuric acid) they give generally a blue coloration which turns to a green and finally to a brown colour.Advertisement
This serves a double purpose, bringing up from the soil continually a supply of the soluble mineral matters necessary for their metabolic processes, \vhich only enter the plant in solutions of extreme dilution, and at the same time keeping the plant cool by the process of evaporation.
It is also readily soluble in solutions of the caustic alkalis, slightly soluble in aqueous ammonia solution, and almost insoluble in sodium carbonate solution.
Species of aphides may be removed by tobacco infusion, soapsuds or other solutions.
As regards processes of manufacture soaps may be made by the direct combination of fatty acids, separated from oils, with alkaline solutions.
Experimental conditions were thoroughly worked out; the necessity of working with hot or cold solutions was clearly emphasized; and the employment of small quantities of substances instead of the large amounts recommended by Klaproth was shown by him to give more consistent results.
Sometimes it is necessary to allow the solution to stand for a considerable time either in the warm or cold or in the light or dark; to work with cold solutions and then boil; or to use boiling solutions of both the substance and reagent.
Unfortunately, the term normal is sometimes given to solutions which are strictly decinormal; for example, iodine, sodium thiosulphate, &c. In technical analysis, where a solution is used for one process only, it may be prepared so that I cc. is equal to.
Standard solutions are prepared by weighing out the exact amount of the pure substance and dissolving it in water, or by forming a solution of approximate normality, determining its exact strength by gravimetric or other means, and then correcting it for any divergence.
Similarly, normal solutions of hydrochloric and nitric acids can be prepared.
In the second group, we may notice the application of litmus, methyl orange or phenolphthalein in alkalimetry, when the acid or alkaline character of the solution commands the colour which it exhibits; starch paste, which forms a blue compound with free iodine in iodometry; potassium chromate, which forms red silver chromate after all the hydrochloric acid is precipitated in solutions of chlorides; and in the estimation of ferric compounds by potassium bichromate, the indicator, potassium ferricyanide, is placed in drops on a porcelain plate, and the end of the reaction is shown by the absence of a blue coloration when a drop of the test solution is brought into contact with it.
In acid copper solutions, mercury is deposited before the copper with which it subsequently amalgamates; silver is thrown down simultaneously; bismuth appears towards the end; and after all the copper has been precipitated, arsenic and antimony may be deposited.
Lead and manganese are partially separated as peroxides, but the remaining metals are not deposited from acid solutions.
The general procedure is to make a series of standard solutions containing definite quantities of the substance which it is desired to estimate; such a series will exhibit tints which deepen as the quantity of the substance is increased.
A known weight of the test substance is dissolved and a portion of the solution is placed in a tube similar to those containing the standard solutions.
When precipitated from solutions it forms red tetragonal crystals, which, on careful heating, give a yellow rhombic form, also obtained by crystallization from the fused substance, or by sublimation.
In the case of separation from solutions, either by crystallization or by precipitation by double decomposition, the temperature, the concentration of the solution, and the presence of other ions may modify the form obtained.
In the case of sodium dihydrogen phosphate, NaH 2 PO 4 H 2 O, a stable rhombic form is obtained from warm solutions, while a different, unstable, rhombic form is obtained from cold solutions.
From supersaturated solutions the form unstable at the temperature of the experiment is, as a rule, separated, especially on the introduction of a crystal of the unstable form; and, in some cases, similar inoculation of the fused substance is attended by the same result.
This may be effected by burning phosphorus in a confined volume of air, by the action of an alkaline solution of pyrogallol on air, by passing air over heated copper, or by the action of copper on air in the presence of ammoniacal solutions.
If the gas be mixed with the vapour of carbon disulphide, the mixture burns with a vivid lavender-coloured flame Nitric oxide is soluble in solutions of ferrous salts, a dark brown solution being formed, which is readily decomposed by heat, with evolution of nitric oxide.
Nascent hydrogen reduces it to hydroxylamine (q.v.), whilst solutions of hypochlorites oxidize it to nitric acid.
The silver salt is a bright yellow solid, soluble in dilute sulphuric and nitric acids, and may be crystallized from concentrated solutions of ammonia.
In the Flos equations with negative values of the unknown quantity are also to be met with, and Leonardo perfectly understands the meaning of these negative solutions.
Albumins (as classified above) are soluble in water, dilute acids and alkalies, and in saturated neutral salt solutions; they are coagulated by heat.
The globulins are insoluble in water and in dilute acids, but soluble in alkalies and in neutral salt solutions; these solutions are coagulated on boiling.
They are loose, white, non-hygroscopic powders, soluble in water and salt solutions, and have an acid reaction; they give the colour reactions of albumins.
They are quite insoluble in water and in salt solutions, and difficultly soluble in dilute acids and alkalies.
It forms shiny, homogeneous masses, quite insoluble in cold water and in salt solutions, but soluble in alkalies.
Melanins obtained from tumours form black, shiny masses; they are insoluble in water, neutral salt solutions, dilute acids and in the common organic solvents.
Soon afterwards, William Cruickshank decomposed the magnesium, sodium and ammonium chlorides, and precipitated silver and copper from their solutions - an observation which led to the process of electroplating.
Berzelius stated that neutral salt solutions could be decomposed by electricity, the acid appearing at one pole and the metal at the other.
This observation showed that nascent hydrogen was not, as had been supposed, the primary cause of the separation of metals from their solutions, but that the action consisted in a direct decomposition into metal and acid.
Similar relations were found to hold and the amounts of chemical change to be the same for the same electric transfer as in the case of solutions.
In aqueous solutions, for instance, a few hydrogen (H) and hydroxyl (OH) ions derived from the water are always present, and will be liberated if the other ions require a higher decomposition voltage and the current be kept so small that hydrogen and hydroxyl ions can be formed fast enough to carry all the current across the junction between solution and electrode.
This leads us to examine more closely the part played by water in the electrolysis of aqueous solutions.
If two solutions containing the salts AB and CD be mixed, double decomposition is found to occur, the salts AD and CB being formed till a certain part of the first pair of substances is transformed into an equivalent amount of the second pair.
It should be noted, however, that another cause would be competent to explain the unequal dilution of the two solutions.
For certain concentrated solutions the transport number is found to be greater than unity; thus for a normal solution of cadmium iodide its value is I 12.
Many solutions in which the transport numbers vary at high concentration often become simple at greater dilution.
For instance, to take the two solutions to which we have already referred, we have of ions between molecules at the instants of molecular collision only; during the rest of the life of the ions they were regarded as linked to each other to form electrically neutral molecules.
If a solution, let us say of sugar, be confined in a closed vessel through the walls of It is probable that in both these solutions complex ions exist at fairly high concentrations, but gradually gets less in number and finally disappear as the dilution is increased.
Van Hoff pointed out that measurements of osmotic pressure confirmed this value in the case of dilute solutions of cane sugar.
The freezing points and vapour pressures of solutions of sugar are also in conformity with the theoretical numbers.
But when we pass to solutions of mineral salts and acids - to solutions of electrolytes in fact - we find that the observed values of the osmotic pressures and of the allied phenomena are greater than the normal values.
Results have been obtained for solutions of sugar, where the experimental, number is 1 858, and for potassium chloride, which gives a depression of 3.720.
The second relation, as we have seen, is not a strict consequence of theory, and experiments to examine it must be treated as an investigation of the limits within which solutions are dilute within the thermodynamic sense of the word, rather than as a test of the soundness of the theory.
Corresponding with this result we find that the freezing point of dilute solutions indicates that two pressure-producing particles per molecule are present.
This view of the nature of electrolytic solutions at once explains many well-known phenomena.
Other physical properties of these solutions, such as density, colour, optical rotatory power, &c., like the conductivities, are additive, i.e.
While it seems clear that the conduction in this case is carried on by ions similar to those of solutions, since Faraday's laws apply equally to both, it does not follow necessarily that semi-permanent dissociation is the only way to explain the phenomena.
The evidence in favour of dissociation in the case of solutions does not apply to fused salts, and it is possible that, in their case, a series of molecular interchanges, somewhat like Grotthus's chain, may represent the mechanism of conduction.
An interesting relation appears when the electrolytic conductivity of solutions is compared with their chemical activity.
When the solutions of two substances are mixed, similar considerations to those given above enable us to calculate the resultant changes in dissociation.
Such solutions were called by Arrhenius " isohydric."
The two solutions, then, will so act on each other when mixed that they become isohydric. Let us suppose that we have one very active acid like hydrochloric, in which dissociation is nearly complete, another like acetic, in which it is very small.
In order that the solutions of these should be isohydric and the concentrations of the hydrogen ions the same, we must have a very large quantity of the feebly dissociated acetic acid, and a very small quantity of the strongly dissociated hydrochloric, and in such proportions alone will equilibrium be possible.
The temperature coefficient of conductivity has approximately the same value for most aqueous salt solutions.
The influence of temperature on the conductivity of solutions depends on (I) the ionization, and (2) the frictional resistance of the liquid to the passage of the ions, the reciprocal of which is called the ionic fluidity.
The dissociation theory gives an immediate explanation of the fact that, in general, no heat-change occurs when two neutral salt solutions are mixed.
A current can be obtained by the combination of two metals in the same electrolyte, of two metals in different electrolytes, of the same metal in different electrolytes, or of the same metal in solutions of the same electrolyte at different concentrations.
As an example of a fairly constant cell we may take that of Daniell, which consists of the electrical arrangement - zinc zinc sulphate solution copper sulphate solution copper, - the two solutions being usually separated by a pot of porous earthenware.
In ordinary cells the difference is secured by using two dissimilar metals, but an electromotive force exists if two plates of the same metal are placed in solutions of different substances, or of the same substance at different concentrations.
When the solutions may be taken as effectively dilute, so that the gas laws apply to the osmotic pressure, this relation reduces to E _ nrRT to c1 ey gE c2 where n is the number of ions given by one molecule of the salt, r the transport ratio of the anion, R the gas constant, T the absolute temperature, y the total valency of the anions obtained from one molecule, and c i and c 2 the concentrations of the two solutions.
If we take as an example a concentration cell in which silver plates are placed in solutions of silver nitrate, one of which is ten times as strong as the other, this equation gives E = o 060 X Io 8 C.G.S.
It is now evident that the electromotive force of an ordinary chemical cell such as that of Daniell depends on the concentration of the solutions as well as on the nature of the metals.
The difference of potential between two solutions of a substance at different concentrations can be calculated from the equations used to give the diffusion constants.
On the analogy between this case and that of the interface between two solutions, Nernst has arrived at similar logarithmic expressions for the difference of potential, which becomes proportional to log (P 1 /P 2) where P2 is taken to mean the osmotic pressure of the cations in the solution, and P i the osmotic pressure of the cations in the substance of the metal itself.
Pernambuco rubber, as is the case with most rubbers coagulated by saline solutions, contains a large quantity of water.
These liquids, either alone or mixed, are employed in making the rubber solutions used for technical purposes.
It should be mentioned here, however, that solutions which would deposit their metal on any object by simple immersion should not be generally used for electroplating that object, as the resulting deposit is usually non-adhesive.
Other alloys may be produced, such as bronze, or German silver, by selecting solutions (usually cyanides) from which the current is able to deposit the constituent metals simultaneously.
Since dp4+(-)P+T1(p +q qi 1)!dd4, the solutions of the partial differential equation d P4 =o are the single bipart forms, omitting s P4, and we have seen that the solutions of p4 = o are those monomial functions in which the part pq is absent.
Hence, excluding ao, we may, in partition notation, write down the fundamental solutions of the equation, viz.
In order to obtain the seminvari ants we would write down the (w; 0, n) terms each associated with a literal coefficient; if we now operate with 52 we obtain a linear function of (w - I; 8, n) products, for the vanishing of which the literal coefficients must satisfy (w-I; 0, n) linear equations; hence (w; 8, n)-(w-I; 0, n) of these coefficients may be assumed arbitrarily, and the number of linearly independent solutions of 52=o, of the given degree and weight, is precisely (w; 8, n) - (w - I; 0, n).
Solving the equation by the Ordinary Theory Of Linear Partial Differential Equations, We Obtain P Q 1 Independent Solutions, Of Which P Appertain To S2Au = 0, Q To 12 B U =0; The Remaining One Is Ab =Aobl A 1 Bo, The Leading Coefficient Of The Jacobian Of The Two Forms. This Constitutes An Algebraically Complete System, And, In Terms Of Its Members, All Seminvariants Can Be Rationally Expressed.
Among other subjects at which he subsequently worked were the absorption of gases in blood (1837-1845), the expansion of gases by heat (1841-1844), the vapour pressures of water and various solutions (1844-1854), thermo-electricity (1851), electrolysis (1856), induction of currents (1858-1861), conduction of heat in gases (1860), and polarization of heat (1866-1868).
Lead dioxide, Pb0 2, also known as "puce oxide," occurs in nature as the mineral plattnerite, and may be most conveniently prepared by heating mixed solutions of lead acetate and bleaching powder until the original precipitate blackens.
Lead sulphate, PbSO 4, occurs in nature as the mineral anglesite (q.v.), and may be prepared by the addition of sulphuric acid to solutions of lead salts, as a white precipitate almost insoluble in water (1 in 21,739), less soluble still in dilute sulphuric acid (1 in 36,504) and insoluble in alcohol.
Solutions of lead salts (colourless in the absence of coloured acids) are characterized by their behaviour to hydrochloric acid, sulphuric acid and potassium chromate.
The solutions proposed are two.
The usual test for solutions of aconitine consists in slight acidulation with acetic acid and addition of potassium permanganate, which causes the formation of a red crystalline precipitate.
Manganese, though belonging (with chromium) to the iron group of metals, is commonly classed as a paramagnetic, its susceptibility being very small in comparison with that of the recognized ferromagnetics; but it is remarkable that its atomic susceptibility in solutions of its salts is even greater than that of iron.
In the theory of numbers he furnished solutions of many of P. Fermat's theorems, and added some of his own.
Yet it possesses the great and characteristic merit of generalizing the solutions of his predecessors, exhibiting them all as modifications of one principle.
The salt separates from solutions containing hydrofluoric acid in large plates, which are greenish yellow in colour.
Their chief works are in the shape of commentaries upon the writings of "the philosopher."' Their problems and solutions alike spring from the master's dicta - from the need of reconciling these with one another and with the conclusions of Christian theology.
They are characterized by the deep red colour of their solutions in alkalis.
To this lofty quality of intellect he added a rare sagacity in perceiving analogies, and in detecting the new truths that lay concealed in his formulae, and a tenacity of mental grip, by which problems, once seized, were held fast, year after year, until they yielded up their solutions.
C. Maclaurin, Legendre and d'Alembert had furnished partial solutions of the problem, confining their 1 Annales de chimie et de physique (1816), torn.
Many of the solutions are most ingenious, and some of the constructions of considerable practical importance.
Graphical representation shows that there are two solutions, and that an equation X2= 9a2 may be taken to be satisfied not only by X=3a but also by X= -3a.
On the other hand, the equations q'x = q and yq' = q have, in general, different solutions.
The unknown he terms arithmos, the number, and in solutions he marks it by the final s; he explains the generation of powers, the rules for multiplication and division of simple quantities, but he does not treat of the addition, subtraction, multiplication and division of compound quantities.
Moritz Cantor suspects the influence of Diophantine methods, more particularly in the Hindu solutions of indeterminate equations, where certain technical terms are, in all probability, of Greek origin.
It is also supposed that they anticipated discoveries of the solutions of higher equations.
In this they were completely successful, for they obtained general solutions for the equations ax by = c, xy = ax+by+c (since rediscovered by Leonhard Euler) and cy 2 = ax e + b.
It includes the properties of numbers; extraction of roots of arithmetical and algebraical quantities, solutions of simple and quadratic equations, and a fairly complete account of surds.
In physical chemistry he carried out many researches on the nature and process of solution, investigating in particular the thermal effects produced by the dilution of saline solutions, the variation of the specific heat of saline solutions with temperature and concentration, and the phenomena of liquid diffusion.
Stannic sulphide, SnS 2, is obtained by heating a mixture of tin (or, better, tin amalgam), sulphur and sal-ammoniac in proper proportions in the beautiful form of aurum musivum (mosaic gold) - a solid consisting of golden yellow, metallic lustrous scales, and used chiefly as a yellow "bronze" for plaster-of-Paris statuettes, &c. The yellow precipitate of stannic sulphide obtained by adding sulphuretted hydrogen to a stannic solution readily dissolves in solutions of the alkaline sulphides to form thiostannates of the formula M 2 SnS 31 the free acid, H2SnS3, may be obtained as an almost black powder by drying the yellow precipitate formed when hydrochloric acid is added to a solution of a thiostannate.
Stannous salt solutions yield a brown precipitate of SnS with sulphuretted hydrogen, which is insoluble in cold dilute acids and in real sulphide of ammonium, (NH 4) 2 S; but the yellow, or the colourless reagent on addition of sulphur, dissolves the precipitate as SnS 2 salt.
Stannic salt solutions give a yellow precipitate of SnS 2 with sulphuretted hydrogen, which is insoluble in cold dilute acids but readily soluble in sulphide of ammonium, and is re-precipitated therefrom as SnS2 on acidification.
The solutions are oxidized, precipitated with ammonia, the precipitate dissolved in hydrochloric acid, and re-thrown down by boiling with sodium sulphate.
Strong or weak solutions of these substances also decompose it, producing some alkali nitrate and nitrite, the cellulose molecule being only partially restored, some quantity undergoing oxidation.
Some solutions of nitroglycerin (in ether, acetone, &c.) burn quietly, and the same is the case when it is held in solution or suspension in a colloid substance, as gelatinized guncotton, &c.
Ammonium hydroxide has no appreciable action at ordinary temperatures, but strong solutions of sodium or potassium hydroxides start a decomposition, with rise of temperature, in which some nitrate and always some nitrite is produced.
Some glycerin may be re-formed, but with very strong alkaline solutions little of the glycerin molecule escapes destruction, oxalic acid and several other products resulting.
Alcoholic solutions of the alkalis also produce much nitrite along with some formate and acetate.
Nitroglycerin shaken up with warm very dilute alkaline solutions, as sodium carbonate, for a few minutes only, always yields sufficient nitrite to give the diazoreaction; and, as stated, strong alkaline solutions always produce some nitrite as one of the decomposition products.
It gives mono-metallic salts of the type NC NHM when treated with aqueous or alcoholic solutions of alkalis.
Chrysaniline (diamino-phenylacridinei) forms red-coloured salts, which dye silk and wool a fine yellow; and the solutions of the salts are characterized by their fine yellowish-green fluorescence.
It decomposes solutions of silver nitrate and copper sulphate.
The compounds formed in the first case, which may be either definite chemical compounds or solid solutions, are discussed under Alloys; in this place only combinations with non-metals are discussed, it being premised that the free metal takes part in the reaction.
In order to determine the motion of each stratum, he employed the principle of the conservatio virium vivarum, and obtained very elegant solutions.
It was more fully developed in his Traite des fluides, published in 1744, in which he gave simple and elegant solutions of problems relating to the equilibrium and motion of fluids.
This disease has been successfully treated with a spray of copper sulphate and lime, or sulphate of iron; solutions of these salts prevent the conidia from germinating.
The use of the copper solutions mentioned above may also be recommended as a preventive.
All sugars are colourless solids or syrups, which char on strong heating; they are soluble in water, forming sweet solutions but difficultly soluble in alcohol.
Their solutions are optically active, i.e.
The rotation serves for the estimation of sugar solutions (saccharimetry).
It reduces ammoniacal silver solutions in the cold, and alkaline copper solutions on boiling.
The processes of evaporation and concentration are carried on as they are in a cane sugar factory, but with this advantage, that the beet solutions are freer from gum and glucose than those obtained from sugar-canes, and are therefore easier to cook.
It resembles acetylene in yielding metallic derivatives with ammoniacal copper and silver solutions.
Zinc is also soluble in soda and potash solutions, but not in ammonia.
At a boiling heat, zinc chloride dissolves in any proportion of water, and highly concentrated solutions, of course, boil at high temperatures; hence they afford a convenient medium for the maintenance of high temperatures.
In many of these the application of heat is necessary to bring the substances used into the liquid state for the purpose of electrolysis, aqueous solutions being unsuitable.
Acid solutions of titanates are not precipitated by sulphuretted hydrogen; but ammonium sulphide acts on them as if it were ammonia, the sulphuretted hydrogen being liberated.
The corresponding iodides are obtained by the addition of potassium iodide to solutions of the sulphonates, and are optically active antipodes.
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).
If, however, no porous division be used to prevent the intermingling by diffusion of the anode and cathode solutions, a complicated set of subsidiary reactions takes place.
Many electrolytic methods have been proposed for the purification of sugar; in some of them soluble anodes are used for a few minutes in weak alkaline solutions, so that the caustic alkali from the cathode reaction may precipitate chemically the hydroxide of the anode metal dissolved in the liquid, the precipitate carrying with it mechanically some of the impurities present, and thus clarifying the solution.
The problem was not solved, but the inadequate solutions were excluded, and the data to be considered in any adequate solution were affirmed.
Reference should be made to the articles Chemical Action, Thermochemistry and Solutions, for the theory of the strength or avidity of acids.
It is readily hydrolysed by hot solutions of the caustic alkalis.
But modern work has shown that, although alloys sometimes contain solid solutions, the solid alloy as a whole is often far more like a conglomerate rock than a uniform solution.
Fromm have shown that alloys may be precipitated from dilute solutions by zinc, cadmium, tin, lead and copper.
Other cases could be quoted, but enough has been said to show the importance of solid solutions and their influence on the mechanical properties of alloys.
These uniform solid solutions must not be mistaken for chemical compounds; they can, within limits, vary in composition like an ordinary liquid solution.
The higher eutectic D may correspond to a complex of solid thallium and the compound; but the possible existence of solid solutions makes further investigation necessary here.
We learn also that solid solutions which exist at high temperatures often break up into two materials as they cool; for example, the bronze of fig.
The graphical representation of the properties of alloys can be extended so as to record all the changes, thermal and chemical, which the alloy undergoes after, as well as before, solidification, including the formation and breaking up of solid solutions and compounds.
Traces of ethyl alcohol in solutions are detected and estimated by oxidation to acetaldehyde, or by conversion into iodoform by warming with iodine and potassium hydroxide.
When the gold is finely divided, as in " purple of Cassius," or when it is precipitated from solutions, the colour is ruby-red, while in very thin leaves it transmits a greenish light.
The metal is soluble in solutions of chlorine, bromine, thiosulphates and cyanides; and also in solutions which generate chlorine, such as mixtures of hydrochloric acid with nitric acid, chromic acid, antimonious acid, peroxides and nitrates, and of nitric acid with a chloride.
The genesis of the last three types of deposit is generally assigned to the simultaneous percolation of solutions of gold and silica, the auriferous solution being formed during the disintegration of the gold-bearing metalliferous veins.
Aurous oxide, Au 2 0, is obtained by cautiously adding potash to a solution of aurous bromide, or by boiling mixed solutions of auric chloride and mercurous nitrate.
Light-yellow monoclinic needles of 2KAuC1 4 H 2 O are deposited from warm, strongly acid solutions, and transparent rhombic tables of KAuCl 4.2H 2 O from neutral solutions.
Potassium auricyanide, 2KAu(CN) 4.3H 2 O, is obtained as large, colourless, efflorescent tablets by crystallizing concentrated solutions of auric chloride and potassium cyanide.
Electrolytically, generally applied to the solutions obtained in processes (3) and (4).
Many processes have been suggested in which the gold of auriferous deposits is converted into products soluble in water, from which solutions the gold may be precipitated.
There have also been introduced processes in which the chlorine is generated in the chloridizing vat, the reagents used being dilute solutions of bleaching powder and an acid.
The solutions are well mixed by stirring with wooden poles, and the gold allowed to settle, the time allowed varying from 12 to 72 hours.
The strengths employed depend also upon the mode of precipitation adopted, stronger solutions (up to 0.25% KCN) being used when zinc is the precipitant.
Siemens and Halske, essentially consists in the electrolysis of weak solutions with iron or steel plate anodes, and lead cathodes, the latter, when coated with gold, being fused and cupelled.
Its advantages over the zinc process are that the deposited gold is purer and more readily extracted, and that weaker solutions can be employed, thereby effecting an economy in cyanide.
But if the gold-strength of the bath be maintained, only gold is deposited at the cathode - in a loose powdery condition from pure solutions, but in a smooth detachable deposit from impure liquors.
The tank is of porcelain or glazed earthenware, the electrodes for impure solutions are z in.
Oxidizing agents (ferric chloride, &c.) give a blue precipitate with solutions of its salts.
It is precipitated as the metal from solutions of its salts by the metals of the alkalis and alkaline earths, zinc, iron, copper, &c. In its chemical affinities it resembles arsenic and antimony; an important distinction is that it forms no hydrogen compound analogous to arsine and stibine.
Bismuth dioxide, BiO or Bi 2 O 2, is said to be formed by the limited oxidation of the metal, and as a brown precipitate by adding mixed solutions of bismuth and stannous chlorides to a solution of caustic potash.
The metal can be reduced by magnesium, zinc, cadmium, iron, tin, copper and substances like hypophosphorous acid from acid solutions or from alkaline ones by formaldehyde.
An amor phous form is obtained when tellurium is precipitated from its solutions by sulphur dioxide, this variety having a specific gravity 6.015.
It burns, and also, like sulphuretted hydrogen, precipitates many metals from solutions of their salts.
Tantalum is not affected by alkaline solutions, but is disintegrated when fused with potash.
It is not indeed that these methods have not claimed to solve the questions at issue, but that their solutions have failed to satisfy the larger body of reasonable criticism.
Various solutions have been offered as to the seven emperors designed by the seven heads of the beast, xiii.
One can look on sea-water as a mixture of very dilute solutions of particular salts, each one of which after the lapse of sufficient time fills the whole space as if the other constituents did not exist, and this interdiffusion accounts easily for the uniformity of composition in the sea-water throughout the whole ocean, the only appreciable difference from point to point being the salinity or degree of concentration of the mixed solutions.
Further Physical Properties of Sea-water.---The laws of physical chemistry relating to complex dilute solutions apply to seawater, and hence there is a definite relation between the osmotic pressure, freezing-point, vapour tension and boiling-point by which when one of these constants is given the others can be calculated.
Many double chlorides are known, and may be prepared by mixing solutions of the two components in the requisite proportions.
In the massive state it is insoluble in all acids, but when freshly precipitated from solutions it dissolves in fuming nitric acid.
It is insoluble in acids and exists in several hydrated forms. The osmiates, corresponding to the unknown trioxide 0503, are red or green coloured salts; the solutions are only stable in the presence of excess of caustic alkali; on boiling an aqueous solution of the potassium salt it decomposes readily, forming a black precipitate of osmic acid, H20s04.
The trichloride, OsC1 3, is only known in solution and is formed by the reducing action of mercury on ammoniacal solutions of the tetroxide.
The tetrasulphide, OsS4, is similarly prepared when sulphuretted hydrogen is passed into acid solutions of the tetroxide.
It is a brownish black solid, insoluble in solutions of the alkaline sulphides.
All these solutions were condemned by Plato on the ground that they were mechanical and not geometrical, i.e.
Thus Nicomedes invented the conchoid; Diodes the cissoid; Dinostratus studied the quadratrix invented by Hippias; all these curves furnished solutions, as is also the case with the trisectrix, a special form of Pascal's limacon.
Glauber's salt readily forms supersaturated solutions, in which crystallization takes place suddenly when a crystal of the salt is thrown in; the same effect is obtained by exposure to the air or by touching the solution with a glass rod.
Tt is a monacid base which is readily soluble in solutions of the cans' is alkalis.
Aqueous solutions deposit crystals containing 2, 4 or 6 molecules of water.
Calcium carbonate is obtained as a white precipitate, almost insoluble in water (1 part requiring Io,000 of water for soluticn), by mixing solutions of a carbonate and a calcium salt.
Hot or dilute cold solutions deposit minute orthorhombic crystals of aragonite, cold saturated or moderately strong solutions, hexagonal (rhombohedral) crystals of calcite.
The mineral brushite, CaHPO 4.2H 2 0, which is isomorphous with the acid arsenate pharmacolite, CaHAs04.2H20, is an acid phosphate, and assumes monoclinic forms. The normal salt may be obtained artificially, as a white gelatinous precipitate which shrinks greatly on drying, by mixing solutions of sodium hydrogen phosphate, ammonia, and calcium chloride.
It is insoluble in water; slightly soluble in solutions of carbonic acid and common salt, and readily soluble in concentrated hydrochloric and nitric acid.
It is obtained as rhombic plates by mixing dilute solutions of calcium chloride and sodium phosphate, and passing carbon dioxide into the liquid.
Calcium metasilicate, CaSiO 3, occurs in nature as monoclinic crystals known as tabular spar or wollastonite; it may be prepared artificially from solutions of calcium chloride and sodium silicate.
Sulphuric acid gives a white precipitate of calcium sulphate with strong solutions; ammonium oxalate gives calcium oxalate, practically insoluble in water and dilute acetic acid, but readily soluble in nitric or hydrochloric acid.
These pests can be kept in check by syringing with nicotine, soft-soap and quassia solutions, or by "vaporising" two or three evenings in succession, afterwards syringing the plants with clear tepid water.
Liquid ammonia possesses strong ionizing powers, and solutions of salts in liquid ammonia have been much studied.
The aqueous solutions of all the carbonates when boiled undergo decomposition with liberation of ammonia and of carbon dioxide.
The normal phosphate, (NH4)3P04,is obtained as a crystalline powder, on mixing concentrated solutions of ammonia and phosphoric acid, or on the addition of excess of ammonia to the acid phosphate (NH 4) 2 HPO 4.
When dissolved in water it yields some NaOH and H202; on crystallizing a cold 'solution Na202.8H20 separates as large tabular hexagonal crystals, which on drying over sulphuric acid give Na 2 0 2.2H 2 0; the former is also obtained by precipitating a mixture of caustic soda and hydrogen peroxide solutions with alcohol.
They are strong oxidizing agents and yield alkaline solutions which readily evolve oxygen on heating.
Solutions of sodium sulphite are used as mild antiparasitics.
The gas is rapidly absorbed by solutions of the caustic alkalis, with the production of alkaline carbonates (q.v.), and it combines readily with potassium hydride to form potassium formate.
It Is Easily Soluble In Solutions Of The Caustic Alkalis, Provided They Are Not Too Concentrated, Forming Solutions Of Alkaline Carbonates And Sulphides, Cos 4Kho = K2C03 K 2 S 2H20.
The legs are filled with solutions of zinc sulphate and copper sulphate, the zinc rod being in the zinc sulphate and the copper rod in the copper sulphate.
The solutions are made by dissolving the purest recrystallized sulphate of copper and sulphate of zinc in distilled water.
The process is readily brought about artificially by the addition of sera or chemical solutions to blood containing the parasites.
It is only very sparingly soluble in water, but dissolves readily in solutions of the alkaline iodides and in alcohol, ether, carbon bisulphide, chloroform, and many liquid hydrocarbons.
Its solutions in the alkaline iodides and in alcohol and ether are brown in colour, whilst in chloroform and carbon bisulphide the solution is violet.
Mendeleeff also devoted much study to the nature of such "indefinite" compounds as solutions, which he looked upon as homogeneous liquid systems of unstable dissociating compounds of the solvent with the substance dissolved, holding the opinion that they are merely an instance of ordinary definite or atomic compounds, subject to Dalton's laws.
The process is not very efficient, since the solutions are too dilute and large quantities of liquid have to be handled.
It is soluble in water, but is insoluble in salt solutions.
This problem, also termed the " Apollonian problem," was demonstrated with the aid of conic sections by Apollonius in his book on Contacts or Tangencies; geometrical solutions involving the conic sections were also given by Adrianus Romanus, Vieta, Newton and others.
For a few approximate geometrical solutions, see Leybourn's Math.
Sodium and potassium hydroxide solutions precipitate green chromium hydroxide from solutions of chromic salts; the precipitate is soluble in excess of the cold alkali, but is completely thrown down on boiling the solution.
Chromium in the form of its salts may be estimated quantitatively by precipitation from boiling solutions with a slight excess of ammonia, and boiling until the free ammonia is nearly all expelled.
Solutions of chromic chloride in presence of excess of acid are green in colour.
It has the characteristic appearance of pure silk - a brilliant soft white body with a pearly lustre - insoluble in water, alcohol and ether, but it dissolves freely in concentrated alkaline solutions, mineral acids, strong acetic acid and in ammoniacal solution of oxide of copper.
It is precipitated from hot solutions by alcohol, falling as a white powder.
It is a most perfect non-conductor of electricity, and in its dry state the fibres frequently get so electrically excited as to seriously interfere with their working, so that it becomes necessary to moisten them with glycerin or soapy solutions.
It precipitates many metals from solutions of their salts.
Magnesium hydroxide Mg(OH) 2, occurs native as the minerals brucite and nemalite, and is prepared by precipitating solutions of magnesium salts by means of caustic soda or potash.
It may be prepared by dissolving the metal, its oxide, hydroxide, or carbonate in dilute hydrochloric acid, or by mixing concentrated solutions of magnesium sulphate and common salt, and cooling the mixture rapidly, when the less soluble sodium sulphate separates first.
The magnesium salts may be detected by the white precipitate formed by adding sodium phosphate (in the presence of ammonia and ammonium chloride) to their solutions.
As alkaloids are insoluble in alkaline solutions, the oxide and carbonate - especially the former - may be given in alkaloidal poisoning.
Solutions were not distinguished from definite chemical compounds till John Dalton discovered the laws of definite and multiple proportions, but many earlier observations on the solubility of solids in water and the density of the resulting solutions had been made.
As early as 1788 Sir Charles Blagden (1748-1820) made measurements of the freezing points of salt solutions, and showed that the depression of freezing point was.
Some pairs of liquids are soluble in each other in all proportions, but, in general, when dealing with solutions of solids or gases in liquids, a definite limit is reached to the amount which will go into solution when the liquid is in contact with excess of the solid or gas.
If, on the other hand, the salt of the cryohydrate fails before the ice the water given by the continued fusion dilutes the solution, and we pass along the curve OB which shows the freezing points of a series of solutions of constantly increasing dilution.
Such structures are known as mixed crystals or solid solutions.
The theoretical form of the freezing point diagrams when solid solutions are present depends on the relation between the available energy and the composition in the two phases.
Again, it will be seen that the addition of a small quantity of one component, say B, to the other, A, does not necessarily lower the melting point, as it does with systems with no solid solutions; it is quite as likely to cause it to rise.
The second and third figures, too, show that the presence of solid solutions may simulate the phenomena of chemical combination, where the curve reaches a maximum, and of non-variant systems where we get a minimum.
The fourth figure shows that, in some cases, it should be possible for solid solutions to be present in a limited part of the field only, being absent between the two nearly vertical lines in fig.
As an example we may take the case of mixtures of naphthalene and 13-naphthol, substances which form solid solutions in each other.
But the elucidation of the complicated phenomena of solid solutions would have been impossible without the theoretical knowledge deduced from the principle of available energy.
A familiar example is to be found in solutions of sodium sulphate, which may be cooled much below their saturation point and kept in the liquid state till a crystal of the hydrate Na 2 SO 4 IoH 2 O is dropped in, when solidification occurs with a large evolution of latent heat.
But other relations between the different properties of solutions have been investigated by another series of conceptions which we shall proceed to develop. Some botanical experiments made about 1870 suggested the idea of semi-permeable membranes, i.e.
It was found, for instance, that a film of insoluble copper ferrocyanide, deposited in the walls of a porous vessel by the inward diffusion and meeting of solutions of copper sulphate and potassium ferrocyanide, would allow water to pass, but retained sugar dissolved in that liquid.
Further, in the free surface the solutions of an involatile solute in a volatile solvent, through which surface the vapour of the solvent alone can pass, and in the boundary of a crystal of pure ice in a solution, we have actual surfaces which are in effect perfectly semipermeable.
Bedford, who compared directly the freezing points of dilute solutions with those of the pure solvent in similar conditions by the accurate methods of platinum thermometry.
When the solution ceases to be dilute in the thermodynamic sense of the word, that is, when the spheres of influence of the solute particles intersect each other, this reasoning ceases to apply, and the resulting modification of the gas laws as applied to solutions becomes a matter for further investigation, theoretical or experimental.
Experiments with membranes of copper ferrocyanide have verified this result for solutions of cane-sugar of moderate dilutions.
Equally good comparisons have been obtained for solutions in other solvents such as acetic acid 3.88, formic acid 2.84, benzene 5.30, and nitrobenzene 6.95.
Such, a concordance between theory and experiment not only verifies the accuracy of thermodynamic reasoning as applied to dilute solutions, but gives perhaps one of the most convincing experimental verifications of the general validity of thermodynamic theory which we possess.
Since, in dilute solutions, the osmotic pressure has the gas value, we may apply the gas equation PV=nRT =npvi to osmotic relations.
The experiments of Raoult on solutions of organic bodies in water and on solutions of many substances in some dozen organic solvents have confirmed this result, and therefore the theoretical value of the osmotic pressure from which it was deduced.
Dilute solutions of substances such as cane-sugar, as we have seen, give experimental values for the connected osmotic properties - pressure, freezing point and vapour pressure - in conformity with the theoretical values.
Now measurements of osmotic properties of these solutions show that their osmotic pressures are abnormally great and that, at extreme dilution, the ratio of their osmotic pressures to that of equivalent solutions of non-electrolytes is equal to the number of ions indicated by the electrolytic properties.
In some solutions such as those of sugar the change in volume on dilution is nearly equal to the volume of solvent added; V' then becomes equal to V, the specific volume of the solvent.
The difference in the two slopes for water and ice is dp/dT - dp'/d T=L/Tv, Solutions.
Frazer, who have made direct measurements of osmotic pressure of solution of cane-sugar, have also measured the freezing points of corresponding solutions.
The corresponding correction in solutions consists in counting only the volume of the solvent in which the solute is dissolved, instead of the whole volume of the solution.
The conceptions of osmotic pressure and ideal semi-permeable membranes enable us to deduce other thermodynamic relations between the different properties of solutions.
By an imaginary cycle of operations we may then justify the application to solutions of the latent heat equation which we have already assumed as applicable.
In a very dilute solution no appreciable heat is evolved or absorbed when solvent is added, but such heat effects are generally found with more concentrated solutions.
The older observers, noticing the heat effects which often accompany dissolution, regarded solutions as chemical compounds of varying composition.
Boltzmann offered a demonstration of the law of osmotic pressure in dilute solutions, based on the idea that the mean energy of translation of a molecule should be the same in the liquid as in the gaseous state.
In the limit of dilution when n is very small compared with N this gives Raoult's experimental law that the relative lowering is n/N, which we deduced from the osmotic law, and conversely from which the osmotic law follows, while for more concentrated solutions agreement is obtained by assigning arbitrary values to a, which, as we have seen, is 5 in the case of cane-sugar.
The special properties of these solutions are dealt with under Electrolysis and Electric conduction, § In Liquids.
Some of these colloids dissolve in water or other liquids to form solutions called by Graham hydrosols; Graham named the solids formed by the setting or coagulation of these liquids hydrogels.
Solutions of colloids in solvents such as water and alcohol seem to be divisible into two classes.
In some solutions they are visible under a good microscope.
In yet other solutions, the particles are smaller again, and seem to approach in size the larger molecules of crystalloid substances.
Moller also in 1887 succeeded in growing small lichen-thalli without their algal constituent (gonidia) on nutritive solutions; in the case of Calicium pycnidia were actually produced under these conditions.
During his residence in Kendal, Dalton had contributed solutions of problems and questions on various subjects to the Gentlemen's and Ladies' Diaries, and in 1787 he began to keep a meteorological diary in which during the succeeding fifty-seven VII.
Many metals, of which copper, silver and nickel are types, can be readily won or purified by the electrolysis of aqueous solutions, and theoretically it may be feasible to treat aluminium in an identical manner.
Aluminium hydrate, Al(OH) 3, is obtained as a gelatinous white precipitate, soluble in potassium or sodium hydrate, but insoluble in ammonium chloride, by adding ammonia to a cold solution of an aluminium salt; from boiling solutions the precipitate is opaque.
The free pararosaniline, C19H19N30, and rosaniline, C20H21N30, may be obtained by precipitating solutions of their salts with a caustic alkali, colourless precipitates being obtained, which crystallize from hot water in the form of needles or plates.
They do not reduce silver solutions, and are not so readily oxidized as the aldehydes.
The yeast-conidia, which bud off from the conidia or their resulting mycelium when sown in nutrient solutions, are developed in successive crops by budding exactly as in the yeast plant, but they cannot ferment sugar solutions.
In these solid solutions, as in aqueous ones, the ratios in which the different chemical substances are present are not fixed or definite, but vary from case to case, not per saltum as between definite chemical compounds, but by infinitesimal steps.
The different substances are as it were dissolved in each other in a state which has the indefiniteness of composition, the absolute merging of identity, and the weakness of reciprocal chemical attraction, characteristic of aqueous solutions.
This salt is a colourless crystalline substance of composition CH30 C6H4 N2 CN HCN 2H20, and has the properties of a metallic salt; it is very soluble in water and its solution is an electrolyte, whereas the solutions of the synand anticompounds are not electrolytes.
On mixing dilute solutions of the diazonium hydroxide and the alkali together, it is found that the molecular conductivity of the mixture is much less than the sum of the two electrical conductivities of the solutions separately, from which it follows that a portion of the ions present have changed to the non-ionized condition.
Dixon); by passing air through solutions of strong bases in the presence of such metals as do not react with the bases to liberate hydrogen; by shaking zinc amalgam with alcoholic sulphuric acid and air (M.
They hydrolyse readily when boiled with solutions of caustic alkalies or mineral acids, yielding the constituent acid and alcohol.
Machinery was invented for disintegrating the leaves and freeing the fibre, and at the same time experiments were made with the view of obtaining it by water-retting, and by means of alkaline solutions and other chemical agencies.
In the chapter (xx.) of that work where Hobbes dealt with the famous problem whose solution he thought he had found, there were left expressions against Vindex (Ward) at a time when the solutions still seemed to him good; but the solutions themselves, as printed, were allowed to be all in different ways halting, as he naively confessed he had discovered only when he had been driven by the insults of malevolent men to examine them more closely with the help of his friends.
Obtaining also a copy of the work as it had been printed before Hobbes had any doubt of the validity of his solutions, Wallis was able to track his whole course front the time of Ward's provocation - his passage from exultation to doubt, from doubt to confessed impotence, yet still without abandoning the old assumption of confident strength; and all his turnings and windings were now laid bare in one of the most trenchant pieces of controversial writing ever penned.
Solutions were furnished by Wallis, Huygens, Wren and others; and Pascal published his own in the form of letters from Amos Dettonville (his assumed name as challenger) to Pierre de Carcavy.
It is also soluble in solutions of the caustic alkalis, with evolution of hydrogen a behaviour similar to that shown by aluminium.
Several basic carbonates are known, being formed by the addition of beryllium salts to solutions of the alkaline carbonates; the normal carbonate is prepared by passing a current of carbon dioxide through water containing the basic carbonate in suspension, the solution being filtered and concentrated over sulphuric acid in an atmosphere of carbon dioxide.
His chief treatise is entitled Difficulties and Solutions of First Principles ('A7ropiae Kai Xuo - Irepi TWV 7rpcorwv apxWV).
Minute vesicular cavities are not infrequently present, sometimes as negative cubes, and these may contain saline solutions or carbon dioxide or gaseous hydrocarbons.
The silicates and aluminates of which Portland cement is composed are believed to exist not as individual units but as solid solutions of each other, these solid solutions taking the form of minerals recognizable as individuals.
Cements such as marine glue are solutions of shellac, india-rubber or asphaltum in benzene or naphtha.
Thallous chloroplatinate, T1 2 PtC1 6, readily obtainable from thallous salt solutions by addition of platinum chloride, is a yellow precipitate soluble in no less than 15,600 parts of cold water.
From solutions containing it as thallous salt the metal is easily precipitated as chloride, iodide, or chloroplatinate by the corresponding reagents.
Sulphuretted hydrogen, in the presence of free mineral acid, gives no precipitate; sulphide of ammonium, from neutral solutions, precipitates T12S as a dark brown or black precipitate, insoluble in excess of reagent.
It is also decomposed by warm aqueous solutions of caustic alkalis, with evolution of ammonia and carbon dioxide.
Urea may be recognized by its crystalline oxalate and nitrate, which are produced on adding oxalic and nitric acids to concentrated solutions of the base; by the white precipitate formed on adding mercuric nitrate to the neutral aqueous solutions of urea; and by the so-called "biuret" reaction.
Liebig (Ann., 18 53, 8 5, p. 289) precipitates dilute solutions of urea with a dilute standard solution of mercuric nitrate, using alkaline carbonate as indicator.
Riegler (ibid., 18 94, 33, p. 49) decomposes urea solutions by means of mercury dissolved in nitric acid, and measures the evolved gas.
It is readily soluble in water and reduces warm silver solutions.
They are readily decomposed by mineral acids with the production of benzoic acid, and on addition of ferric chloride to their neutral solutions give a reddish-brown precipitate of ferric benzoate.
Similar liquids are obtained with a basis of sodium (" eau de Javel "), by passing chlorine into solutions of sodium carbonate.
This is the term applied to certain deposits of alkaline salts, or their solutions, which occur, sometimes in very large quantities, in various parts of the world.
Gallium forms colourless salts, which in neutral dilute aqueous solutions are converted on heating into basic salts.
In neutral solutions, zinc gives a precipitate of gallium oxide.
Another remarkable fact is that these substances yield coloured solutions in organic solvents; triphenylmethyl gives a yellow solution, whilst ditolylphenyl and tritolylmethyls give orange solutions which on warming turn to a violet and to a magenta, the changes being reversed on cooling.
It appears probable that the solutions contain a quinonoid modification (ssee Gomberg and Cone, Ann., 1909, 37 0, p. 142).
No Doubt There Must Be Approximate Relations Between The Atomic And Molecular Heats Of Similar Elements And Compounds, But Considering The Great Variations Of Specific Heat With Temperature And Physical State, In Alloys, Mixtures Or Solutions, And In Allotropic Or Other Modifications, It Would Be Idle To Expect That The Specific Heat Of A Compound Could Be Accurately Deduced By Any Simple Additive Process From That Of Its Constituents.
The caustic alkalis added to solutions of nickel salts give a pale green precipitate of the hydroxide, insoluble in excess of the precipitant.
By precipitation of nickel salts with solutions of the alkaline carbonates, basic carbonates of variable composition are obtained.
Raoult (Comptes Rendus, 1886-87) employed other solvents besides water, and showed that the relative lowering for different solvents and different dissolved substances was the same in many cases for solutions in which the ratio of the number of gramme-molecules n of the dissolved substance to the number of molecules N of the solvent was the same, or that it varied generally in proportion to the ratio n/N.
The most important apparent exceptions to Raoult's law in dilute solutions are the cases, (I) in which the molecules of the dissolved substance in solution are associated to form compound molecules, or dissociated to form other combinations with the solvent, in such a way that the actual number of molecules n in the solution differs from that calculated from the molecular weight corresponding to the accepted formula of the dissolved substance; (2) the case in which the molecules of the vapour of the solvent are associated in pairs or otherwise so that the molecular weight m of the vapour is not that corresponding to its accepted formula.
The values thus found agreed in the main with Raoult's law for dilute solutions (see Solutions).
For strong solutions the discrepancies from Raoult's law often become very large, even if dissociation is allowed for.
This assumption coincides exactly with Raoult's law for the relative lowering of vapourpressure, if a = 1, and agrees with it in the limit in all cases for very dilute solutions, but it makes a very considerable difference in strong solutions if a is greater or less than 1.
P. Pfeffer (Osmotische Untersuchungen, Leipzig, 1877) was the first to obtain satisfactory measurements of osmotic pressures of cane-sugar solutions up to nearly I atmosphere by means of semi-permeable membranes of copper ferrocyanide.
Lord Berkeley and Hartley have also verified the theory by direct measurements of the vapour-pressures of the same solutions.
It is slightly soluble in hydrochloric and sulphuric acids, giving purple solutions.
The salt forms large monoclinic prisms; molecules containing 25 and 21 H 2 O separate from solutions crystallized at higher temperatures.
Of the phosphotungstic acids the most important is phosphoduodecitungstic acid, H 3 PW, 2040 nH 2 O, obtained in quadratic pyramids by crystallizing mixed solutions of orthophosphoric and metatungstic acids.