A simple body

The central idea that aided me in undertaking the study of the periodic law of the elements, consists primarily in the absolute distinction between an atom [of e.g. the element carbon] and a simple body [such as diamond or graphite] ([32, p 193]). 

Random substitutional models are used for phases such as the gas phase or simple metallic liquid and solid solutions where components can mix on any atial position which is available to the phase. For example, in a simple body-centred cubic phase any of the components could occupy any of the atomic sites which define the cubic structure as shown below (Fig. 5.1). 

If the few experiments which we have been able to perform have not afforded us that certainty of the existence of bromine as a very simple body which in the present day is properly required, we consider it at least very probable that it is so. The memoir of M. Balard is extremely well drawn up, and the numerous results which he relates would not fail to excite great interest, even if it should be proved that bromine is not a simple body. The discovery of bromine is a very important acquisition to chemistry, and gives M. Balard honorable rank in the career of the sciences. We are of the opinion that this young chemist is every way worthy of the encouragement of the Academy, and we have the honor to propose that his memoir shall be printed in the Recueil des Savants Strangers (16, 29). 

The element is a simple body which actually enters into the mixture [mixtion] of compound bodies [corps composes] and to which they can be finally... 

The circumstance that a body composed of carbon, hydrogen, and oxygen, combines with other bodies, particularly with such as form salts, after the manner of a simple body, proves that there are ternary composed atoms (of the first order) and the radical of benzoic acid is the first example proved with certainty, of a ternary body possessing the properties of an element. It is true indeed that we have before considered sulphwret of cyanogen (Schwefelcyan) as such, but you are aware that its combinations may be viewed as sulphurets and the body itself seems to be a sulphuret of cyanogen. 

He pointed out that we have no certainty that- the hydrated sulphuric acid really contains water or the sulphate of soda, oxide of sodium and that, instead of the formula HO,SO, we might with better reason adopt the forrhula H,SO for the acid, which would thus come to be considered a hydrogen add, differing from hydrochloric acid only in containing a compound radical, SO, instead of a simple one. Cl. But, in the first place, chlorine may not be really a simple body and secondly, if it were so, we know that compound radicals exist, performing exactly the part which is here ascribed to the hypothetical body SO,. 

Oxygenated muriatic acid is not decomposed by charcoal, and it might be supposed from this fact that... this gas is a simple body. 

The Power of Connectivity—Stoichiometry The last two formulae of sand, [Si02loo or simply Si02, show that Si and O combine in an atomic ratio of 1 2. Thus, even though the molecule may have zillions of atoms, still the basic ratio of the two constituents remains 1 2. Ever since Lavoisier showed the power of quantitative analysis in chemistry and defined the notion of an element as a simple body, chemists tried to find quantitative relationships between the combined weights... 

Oxygenated muriatic gas is not decomposed by carbon, and it can be supposed from this fact and those reported in this memoir, that this gas is a simple body. The phenomena which it presents are equally well explained by this hypothesis we do not, however, seek to defend it, since it seems to us that they are still better explained by regarding oxymuriatic acid as a compound body. ... 

After this account, one cannot avoid comparing iodine with chlorine and the new acid with muriatic acid. . . iodine is an element [ acide by mistake in original] and forms a compound with hydrogen, or else this latter acid is a compound of water and an unknown base, and iodine is this base united to oxygen. The first hypothesis appears more probable than the other and it adds probability to that which regards oxymuriatic acid as a simple body. ... 

Faraday in his diary says Ampere, Clement, and Desormes came this morning [23 November 1813] to show Sir H. Davy a new substance, discovered, about two years ago, by M. Courtois, saltpetre manufacturer. The process by which it is obtained is not yet publicly known. It is said to be procured from a very common substance, and in considerable quantities . Very little information would seem to have been given to Davy, who at first (says Faraday) thought it was a compound of chlorine and an unknown body, although the entry for the same day says Davy now thinks it contains no chlorine . On I December, Faraday says, Davy had made many experiments on it with his travelling apparatus M. Clement has lately read a paper on it... in which he says it is procured from the ashes of sea-weeds by lixiviation and treatment with sulphuric acid. He conceives it to be a new supporter of combustion. On 3 December, Davy was working on it in Chevreul s laboratory and on ii December he concluded that as yet it must be considered as a simple body . 

In a formula representing two volumes of vapour, the sum of the numbers of atoms (proportional numbers) of hydrogen, nitrogen, phosphorus, arsenic, and halogens is an even number. He then introduces the unitary view, in which a molecule is regarded as an edifice, a unique system formed by the assembly in a determinate but unknown order, of infinitely small particles called atoms , either of the same kind in a simple body or of different kinds in a compound body. No distinction is to be made between the two kinds of molecules. He says the equivalent depends on what other body, in what functions, with what proportions, this equivalent is to correspond . 

We admit that each molecule of a simple body is divisible at least into two parts, which we will call atoms these molecules can be divided only in the case of combinations. The atom of Gerhardt represents the smallest quantity of a body which can exist in a compound. My molecule represents the smallest quantity of a body which must be used to effect a combination, a quantity which is divided into two by the act of combination. Thus, Cl may enter into a combination, but to do this Ch must be used. As for the very rare abnormal compounds which are encountered, they must be represented thus chlorhydrate of ammonia CIH N, indicating that the molecule is CIH N, but that under the influence of heat it is divided in two on passing to the gaseous state. ... 

Lavoisier drew no distinction between the concepts of an element and a simple body . They were clearly stated only in the 19th century owing to the development of the atomic and molecular theory and to the work of D. I. Mendeleev. 

Hydrofluoric acid entered the category of reliably classified chemical compounds and scientists gradually came to believe that it contained a new chemical element. This opinion was strengthened by A. Lavoisier who included the radical of hydrofluoric acid radical fluorique) as a simple body into The Table of Simple Bodies . But Lavoisier was also wrong he thought that the acid contained oxygen. His mistake was, however, understandable since at that time chemists believed that oxygen was an indispensable constituent of all acids. 

Phlogiston is either a simple body or a compound of the element of fire with a rare body such that the gravity of the compound is less than that of air. De Morveau was convinced that his theory was different from Chardenon s. 

On calcination, mercury cannot have lost phlogiston since experiment shows that it has gained a new principle. How can the increase in weight be reconciled with the loss of one of the constituent principles The cause of the increase in weight on calcination is to be sought, with Jean Rey, in the atmosphere. Air is to be considered under two states, free and combined. In the first it is a simple body, an element. Which part of the atmosphere calcines metals, the elastic fluid pure and simple, or this combined so as to form an acid, or one of the other fluids found in the air Experiment must decide. 

Heat balance equation of a simple body. Tbe Newton law of cooling... 

Linear differential equation of first order called the heat balance equation of a simple body, has found wide application in calorimetry and thermal analysis as mathematical models used to elaborate various methods for the determination of heat effects. It is important to define the conditions for correct use of this equation, indicating all simplifications and limitations. They can easily be recognized from the assumption made to transform the Fourier-Kirchhoff equation into the heat balance equation of a simple body. 

Equations (1.99) and (1.100) are commonly known as the heat balance equations of a simple body. From the above considerations, it is clear that these heat balance equations and the Fourier-Kirchhoff equation Piq. (1.87)] are equivalent to each other when ... 

We compare Eq. (2.11), which describes the dynamic properties of an inertial object, with the heat balance equation of a simple body [Eq. (1.99)]. 

To evaluate the time constant on the basis of the heat balance equation of a simple body, different input functions are used. Consider the determination of rby applying the input step function [Eq. (2.45)] under conditions where the initial temperatures of the calorimeter and isothermal shield are the same. Equation (2.19) can then be written in the form... 

In the dynamic method ( 3.2.6), the calorimeter is treated as a simple body of uniform temperature. The detailed form of Eq. (1.148) is then a heat balance equation of a sint5)le body. The dynamic method is a one of the most frequently used in the determination of total heat effects and thermokinetics. 

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