Proportions law of constant

The Law of Constant Proportion" -- The same chemical compound always contains the same elements, and there is a constant ratio between the weights of the constituent elements present. 

Berthollet (1748-1822) denied the tmth of the law of constant proportion, and a controversy ensued between this chemist and Proust (1755-1826), who undertook a research to settle the question, the results of which were in entire agreement with the law, and were regarded as completely substantiating it. 

The proportions of the constituents of air vary a little in different localities, but even this small variation is not found with pure chemical compounds—law of constant proportions. Hence, not all the nitrogen and oxygen are combined. 

The first strides after recognition of mass conservation led to the formulation of several phenomenological laws of chemical composition, such as the laws of constant proportions, multiple proportions and eguivalent proportions, found to be obeyed during interaction between chemical substances. These laws served to catalogue and systematize a large body of empirical... 

HISTORICAL REMARKS. THE LAWS OF CONSTANT PROPORTIONS, SIMPLE MULTIPLE PROPORTIONS, AND COMBINING WEIGHTS... 

The Law of Constant Proportions. Different samples of a substance contain elements iti the same propotlions. 

The law of constant proportions was enunciated by the French chemist Joseph Louis Proust (1754-1826) in 1799. For several years it was attacked vigorously by Claude Louis Bertholet (1748-1822), who contended that the composition of the compound depended on the way in which it was prepared. Proust defended the law by pointing out that the materials described by Bertholet as exceptions were mixtures (of different lead oxides, of mercurous salts and mercuric salts, etc.) or solutions. Accurate data showing constancy of composition of the substances investigated to 1 part in 100,000 were first reported by the Belgian chemist J. S. Stas in 1865. 

Historical development the laws of constant proportions, simple multiple proportions, and combining weights. 

The almost invariant yield when varying amounts of iodine are used provides a clear demonstration of the Law of Constant Proportions (/. L. Proust, l/VV). 

And so it went on down the line until Doc reached me. Each answer in turn had been demolished roundly. By this time Doc had dismounted from his high perch and was standing about three feet in front of me. In answer to his pointing finger, I blurted out,. . . The Law of Constant Proportion. ... 

Let me tell you. Isotopes are things (and here he leaned over to within about 12 inches of me)—are things that spit in the face of the Law of Constant Proportion. ... 

These laws played a significant part in Dalton s development of his atomic theory (1808). See conservation of mass, law of constant proportions, law of equivalent proportions, law of multiple proportions, law of. 

The law of constant composition states that the proportions of the elements in a compound are always the same, no matter how the compound is made. It is also called the law of constant proportions or definite proportions. 

Another important consequence of Dalton s hypothesis that matter consists of atoms was that it provided an explanation of the long recognized law of constant proportion. As Richter had pointed out, when any two elements combine together. 

Berzelius, Jons Jakob (1779-1848) A physician and chemist born in Sweden, Berzelius was secretary of the Royal Swedish Academy of Sciences for thirty years. He is credited with discovering the law of constant proportions for inorganic substances and was the first to distinguish organic from inorganic compounds. He developed a system of chemical symbols and a table of relative atomic weights that are stiU in use. In addition to coining such chemical terms as protein, catalysis, polymer, and isomer, he identified the elements cerium, selenium, silicon, and thorium. 

The work of Berthollet on affinity in 1799-1803 (see Vol. IV), with its assumption that chemical reactions are usually incomplete, and that one substance is divided between two others in a variable ratio dependent upon the mass , as well as his recognition of the importance of reactions in solutions, led him to the conclusion that the composition of a compound is not constant but variable, sometimes between fixed limits. This was a negation of the law of constant proportions. In his first work on affinity Berthollet says he proposes to investigate the circumstances which modify combination, or the affections of bodies which favour or diminish their chemical action and which can vary the proportions in the combinations which they can form. ... 

These statements, which contain the whole of Dalton s chemical atomic theory, were arrived at completely in September to October 1803, and remained unchanged in all Dalton s later publications. The symbolic representation of the compositions of compounds used by Dalton (his symbol law ) contained implicitly the laws of definite, multiple, and reciprocal proportions, and Dalton does not give verbal statements of these laws. It was asserted that the law of constant proportions would be a better name than the law of definite proportions and that a further law of compound proportions (vi) is necessary, stating that the combining weight of a compound is the sum of the combining weights of its components, which does not follow from the other laws of chemical combination. 

Proust — The Law of Constant Proportions — Klaproth — Valentin Rose — Stromeyer — Kirwan — Wenzel — Richter —... 

Berthollet s attack on the law of constant proportions was mainly delivered in his book on chemical statics, and some further papers. ... 

The law of constant proportions was first stated by Proust as early as 1797 in a paper on Prussian blue, in which he clearly recognised that iron forms two definite oxides with 27 and 48 per cent of oxygen, and says ... 

Dalton s atomic theory and Wollaston s experiments (see p. 701) were criticised by Berthollet and he maintained his theory of indefinite proportions in certain cases. Ladenburg pointed out that the work of Richter, Dalton s atomic theory, Gay-Lussac s law of gaseous volumes, andthe work of Berzelius on combining proportions, had by then reinforced Proust s arguments, and nearly all chemists had returned to the view (held, for example, by Bergman) that chemical compounds were of definite composition. Most chemists decided in favour of Proust about 1808. Unfortunately, in rejecting Berthol-let s law of indefinite proportions, they also put aside the correct law of mass action, which was not really incompatible with the law of constant proportions and the atomic theory. Chemists then were interested in other matters, Probably the adoption of Dalton s atomic theory was at least as important as Proust s researches in the neglect of Berthollet s theory of variable proportions. ... 

When concentrated hydrochloric acid is added to a blue solution of copper sulphate, the colour becomes progressively green owing to the formation of copper chloride if 100 parts of each acid divide 100 of oxide of copper between them so that the sulphuric acid takes 80 and the hydrochloric 20, the part of each acid really combined with the oxide is neutralised according to the law of constant proportions, whilst the rest of the acid is free, so that the surplus of each of these acids is employed in counterbalancing the surplus of its antagonist . Berzelius thinks this single example is sufficient to show that the principle of Berthollet s theory is not inconsistent with the laws of chemical proportions , and the results of his experiments follow as necessary consequences from the views of the corpuscular theory. , ... 

In 1785 the French chemist Antoine Laurent Lavoisier (1743-1794) showed clearly that there is no change in mass during a chemical reaction — e mass of the products is equal to the mass of the reacting substances. another general law, the law of constant proportions, was... 

Dalton stated the hypothesis that elements consist of atoms, all of the atoms of one element being identical, and that compounds result from the combination of a certain number of atoms of one element with a certain number of atoms of another element (or, in general, from the combination of atoms of two or more elements, each in definite number). In this way he could give a simple explanation of the law of conservation of mass, and also of the law of constant proportions. 

Of what value are the law of constant proportions and the law of multiple proportions in arguing for the acceptance of the atomic theory ... 

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