noun
definition
Any specific chemical element or chemical compound or alloy.
definition
An artificial chemical compound.
definition
An addictive drug.
adjective
definition
Of or relating to chemistry.
definition
Of or relating to a material or processes not commonly found in nature or in a particular product.
definition
Of or relating to alchemy.
Examples of chemical in a Sentence
The advances were not merely mechanical but chemical as well.
The chemical smell suggested they were going in the right direction.
In both these doctrines of a priori science Descartes has not been subverted, but, if anything, corroborated by the results of experimental physics; for the so-called atoms of chemical theory already presuppose, from the Cartesian point of view, certain aggregations of the primitive particles of matter.
But on account of experimental errors in weighing and measuring, and through loss of material in the transfer of substances from one vessel to another, such analyses are rarely trustworthy to more than one part in about Soo; so that small changes in weight consequent on the chemical change could not with certainty be proved or disproved.
Photosynthesis is what converts lightenergy from the sun into chemical energy for plants.
The chemical constitution is not certain.
This was the principle of the chemical telegraph proposed by Edward Davy in 1838 and of that proposed by Bain in 1846.
The chemical characters of the well-waters, the irregular distribution of the water-pressure, the distribution of the underground thermal gradients, and the occurrence in some of the wells of a tidal rise and fall of a varying period, are facts which are not explained on the simple hydrostatic theory.
There are well-known chemical works at Dombasle (close to Nancy) and Chauny (Aisne) and in Rhhne.
The chemical laboratory in connexion with the school was, when first instituted, the only one in England for teaching purposes, and the museum is now reputed to be the best pharmaceutical one in the world, the library now containing about 13,000 volumes.
But the subject requires elucidation from both chemical and biological points of view.
The society has also established a chemical research laboratory, in which much useful work has been done in connexion with the national pharmacopoeia under the direction of the Pharmacopoeia Committee of the Medical Council.
The first chemical change suggested is an interaction between carbon dioxide and water, under the influence of light acting through chlorophyll, which leads to the simultaneous formation of formaldehyde and hydrogen peroxide.
The earliest discoveries in inorganic chemistry are to be found in the metallurgy, medicine and chemical arts of the ancients.
In any attempts to gain an insight into the relations between the physical properties and chemical composition of substances, the fact must never be ignored that a comparison can only be made when the particular property under consideration is determined under strictly comparable conditions, in other words, when the molecular states of the substances experimented upon are identical.
He regarded these anomalies as solely due to the chemical nature of the elements, and ignored or regarded as insignificant such factors as the state of aggregation and change of specific heat with temperature.
It is to be noted that although the correlation of melting-point with constitution has not been developed to such an extent as the chemical significance of other physical properties, the melting-point is the most valuable test of the purity of a substance, a circumstance due in considerable measure to the fact that impurities always tend to lower the melting-point.
In the article Thermo Chemistry a general account of heats of formation of chemical compounds is given, and it is there shown that this constant measures the stability of the compound.
He introduced the idea of comparing the refractivity of equimolecular quantities of different substances by multiplying the function (n-1)/d by the molecular weight (M) of the substance, and investigated the relations of chemical grouping to refractivity.
Since molecular refractions are independent of temperature and of the state of aggregation, it follows that molecular dispersions must be also independent of these conditions; and hence quantitative measurements should give an indication as to the chemical composition of substances.
A clear distinction must be drawn between colour and the property of dyeing; all coloured substances are not dyes, and it is shown in the article Dyeing that the property of entering into chemical or physical combination with fibres involves properties other than those essential to colour.
Isomorphism is most clearly discerned between elements of analogous chemical properties; and from the wide generality of such observations attempts have been made to form a classification of elements based on isomorphous replacements.
For a detailed comparison of the isomorphous relations of the elements the reader is referred to P. von Groth, Chemical Crystallography.
Reference may also be made to Ida Freund, The Study of Chemical Composition; and to the Annual Reports of the Chemical Society for 1908, p. 258.
These methods have been purely chemical (either gravimetric or volumetric), physical (determinations of the density of nitrogen, nitric oxide, &c.) or physicochemical.
It is the seat of extensive cotton, iron, chemical and allied industries.
In 1781 he followed this up with an introductory manual of Chemical Essays.
The study of the differentiation of protoplasm was at that time seldom undertaken, and no particular attention was paid either to fixing it, to enable staining methods to be accurately applied to it, or to studying the action of chemical reagents upon it.
These vary considerably in completeness with its age; in its younger parts the outer cells wall undergoes the change known as cuticularization, the material being changed both in chemical composition and in physical properties.
In addition, certain inorganic salts, particularly certain compounds of potassium, are apparently necessary, but they seem to take no part in the chemical changes which take place.
There is no direct connection between the two, the oxygen is absorbed almost immediately by the protoplasm, and appears to enter into some kind of chemical union with it.
It has been suggested by several botanists, with considerable plausibility, that the ultra-violet or chemical rays can be absorbed and utilized by the protoplasm without the intervention of any pigment such as chlorophyll.
The protoplasm is sensitive to particular influences, perhaps of vibraticn, or of contact or of chemical action.
The colour varies somewhat with the chemical composition, being grey or colourless in chlorargyrite, greenish-grey in embolite and bromargyrite, and greenish-yellow to orange-yellow in iodembolite.
This section is restricted to an account of the relations existing between physical properties and chemical composition.
Other branches of this subject are treated in the articles Chemical Action; Energetics; Solution; Alloys; Thermochemistry.
The existence of a fundamental principle, unalterable and indestructible, prevailing alike through physical and chemical changes, was generally accepted.
At the same time, however, there were many who, opposed to the Paracelsian edefinition of chemistry, still labored at the problem of the alchemists, while others gave much attention to the chemical industries.
First and foremost, he demanded that the balance must be used in all investigations into chemical changes.
The introduction of hydroxyl groups into the benzene nucleus gives rise to compounds generically named phenols, which, although resembling the aliphatic alcohols in their origin, differ from these substances in their increased chemical activity and acid nature.
Analytical Chemistry This branch of chemistry has for its province the determination of the constituents of a chemical compound or of a mixture of compounds.
He realized that the composition by weight of chemical compounds was of the greatest moment if chemistry were to advance.
Since then the subject has been extensively studied, more particularly by Alexander Classen, who has summarized the methods and results in his Quantitative Chemical Analysis by Electrolysis (1903).
The ever-increasing importance of the electric current in metallurgy and chemical manufactures is making this method of great importance, and in some cases it has partially, if not wholly, superseded the older methods.
A physicist, however, does more than merely quantitatively determine specific properties of matter; he endeavours to establish mathematical laws which co-ordinate his observations, and in many cases the equations expressing such laws contain functions or terms which pertain solely to the chemical composition of matter.
The limiting law expressing the behaviour of gases under varying temperature and pressure assumes the form pv= RT; so stated, this law is independent of chemical composition and may be regarded as a true physical law, just as much as the law of universal gravitation is a true law of physics.
It may be surmised that the quantitative measures of most physical properties will be found to be connected with the chemical nature of substances.
In the investigation of these relations, the physicist and chemist meet on common ground; this union has been attended by fruitful and far-reaching results, and the correlation of physical properties and chemical composition is one of the most important ramifications of physical chemistry.
Another branch, related to energetics, is concerned with the transformation of chemical energy into other forms of energy - heat, light, electricity.
Combustion is a familiar example of the transformation of chemical energy into heat and light; the quantitative measures of heat evolution or absorption (heat of combustion or combination), and the deductions therefrom, are treated in the article Thermochemistry.