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Encyclopedia > Chemical substance
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Water and steam are two different forms of the same chemical substance
Water and steam are two different forms of the same chemical substance

A chemical substance is a material with a definite chemical composition. It is a concept that became firmly established in the late eighteenth century after work by the chemist Joseph Proust on the composition of some pure chemical compounds such as basic copper carbonate.[1] He deduced that: "All samples of a compound have the same composition; that is, all samples have the same proportions, by mass, of the elements present in the compound". This became known as the law of constant composition[2]. Later with the advancement of methods for chemical synthesis particularly in the realm of organic chemistry; the discovery of many more chemical elements and new techniques in the realm of analytical chemistry used for isolation and purification of elements and compounds from chemicals that led to the establishment of modern chemistry, the concept was defined as is found in most chemistry textbooks. However, there are some controversies regarding this definition mainly because the large number of chemical substances reported in chemistry literature need to be indexed. Image File history File links Nuvola_apps_edu_science. ... Image File history File links Download high-resolution version (678x809, 88 KB) Boling water in b/w, own picture File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Chemical substance Boiling ... Image File history File links Download high-resolution version (678x809, 88 KB) Boling water in b/w, own picture File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Chemical substance Boiling ... For other uses, see Concept (disambiguation). ... Joseph Louis Proust (September 26, 1754 - July 5, 1826) was a French chemist. ... Copper(II) carbonate (often called copper carbonate or cupric carbonate) is a blue-green compound (chemical formula CuCO3) forming most of the patina one sees on weathered brass, bronze, and copper. ... One of the fundamental observations of modern chemistry, the law of definite proportions states that, in a pure compound, the elements combine in definite proportions to each other. ... In chemistry, chemical synthesis is purposeful execution of chemical reactions in order to get a product, or several products. ... Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting primarily of carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, halogens as well... This article does not cite any references or sources. ... Water and steam are two different forms of the same chemical substance A chemical substance is a material with a definite chemical composition. ... For other uses, see Chemistry (disambiguation). ...


A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. A pure chemical substance cannot be separated into other substances by a process that does not involve any chemical reaction and is rarely found in nature. Some typical chemical substances can be diamond, gold, salt (sodium chloride) and sugar (sucrose). Generally, chemical substances exist as solid, liquid, or gas, and may change between these phases of matter with changes in temperature or pressure. H2O and HOH redirect here. ... A ratio is a quantity that denotes the proportional amount or magnitude of one quantity relative to another. ... This article is about the chemistry of hydrogen. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... This article does not cite any references or sources. ... For other uses, see Chemical reaction (disambiguation). ... This article is about the mineral. ... GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ... Edible salt is mostly sodium chloride (NaCl). ... R-phrases 36 S-phrases none Flash point Non-flammable Related Compounds Other anions NaF, NaBr, NaI Other cations LiCl, KCl, RbCl, CsCl, MgCl2, CaCl2 Related salts Sodium acetate Supplementary data page Structure and properties n, εr, etc. ... This article is about sugar as food and as an important and widely traded commodity. ... Flash point N/A Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Sucrose (common name: table sugar, also called saccharose) is a disaccharide (glucose + fructose) with the molecular formula C12H22O11. ... For other uses, see Solid (disambiguation). ... For other uses, see Liquid (disambiguation). ... Gas can also refer to gasoline and natural gas and also hydrogen. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... For other uses, see Temperature (disambiguation). ... This article is about pressure in the physical sciences. ...

Contents

Defining

Chemical substances (also sometimes referred to as a pure substances) are often defined as any material with a definite chemical composition in most introductory general chemistry textbooks.[3] According to this definition a chemical substance can either be a pure chemical element or a pure chemical compound. However, there are exceptions to this definition, a pure substance can also be defined as a form of matter that has both definite composition and distinct properties.[4] and the chemical substance index published by CAS also includes several alloys of uncertain composition.[5] This article is about matter in physics and chemistry. ... Chemical Abstracts Service (CAS) is a division of the American Chemical Society, and produces Chemical Abstracts, and related products. ... An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resultant material has metallic properties. ...


Elements

Main article: Chemical element

An element is a chemical substance that is made up of a particular kind of atoms and hence cannot be broken down or transformed by a chemical reaction into a different element, though it can be transmutated into another element through a nuclear reaction. This is so, because all of the atoms in a sample of an element have the same number of protons, though they may be different isotopes, with differing numbers of neutrons. The periodic table of the chemical elements A chemical element, or element, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... In nuclear physics, a nuclear reaction is a process in which two nuclei or nuclear particles collide to produce products different from the initial particles. ... For other uses, see Isotope (disambiguation). ...


There are about 120 known elements, about 80 of which are stable, that is, they do not change by radioactive decay into other elements, however the number of chemical substances that are elements can be more than 120, because some elements can occur as more than a single chemical substance (allotropes), for instance oxygen as oxygen and ozone. The majority of elements are classified as metals. These are elements with a characteristic lustre such as iron, copper, and gold. Metals typically conduct electricity and heat well, and they are malleable and ductile.[6] Around a dozen elements[7] such as carbon, nitrogen, and oxygen are classified as non-metals. Non-metals lack the metallic properties described above, they also have a high electronegativity and a tendency to form negative ions called anions. Certain elements such as silicon sometimes resemble metals and sometimes resemble non-metals, and are known as metalloids. Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... Allotropy (Gr. ... For other uses, see Ozone (disambiguation). ... This article is about metallic materials. ... For other uses, see Iron (disambiguation). ... Copper has played a significant part in the history of mankind, which has used the easily accessible uncompounded metal for nearly 10,000 years. ... GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ... Look up malleability in Wiktionary, the free dictionary. ... Ductility is the physical property of being capable of sustaining large plastic deformations without fracture (in metals, such as being drawn into a wire). ... For other uses, see Carbon (disambiguation). ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Together with the metals and metalloids, a nonmetal is one of three categories of chemical elements as distinguished by ionization and bonding properties. ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... An anion is an ion with negative charge. ... Not to be confused with Silicone. ... Metalloid is a term used in chemistry when classifying the chemical elements. ...

See also: List of elements by name

This is a list of chemical elements, sorted by name and color coded according to type of element. ...

Chemical compounds

Main article: Chemical compound

A pure chemical compound is a chemical substance that is composed of a particular set of molecules or ions. Two or more elements combined into one substance, through a chemical reaction, form what is called a chemical compound. A chemical compound can be either atoms bonded together in molecules or crystals in which atoms, molecules or ions form a crystalline lattice. Compounds based primarily on carbon and hydrogen atoms are called organic compounds, and all others are called inorganic compounds. Compounds containing bonds between carbon and a metal are called organometallic compounds. Look up chemical compound in Wiktionary, the free dictionary. ... 3D (left and center) and 2D (right) representations of the terpenoid molecule atisane. ... This article is about the electrically charged particle. ... For other uses, see Chemical reaction (disambiguation). ... A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds. ... 3D (left and center) and 2D (right) representations of the terpenoid molecule atisane. ... For other uses, see Crystal (disambiguation). ... Look up lattice in Wiktionary, the free dictionary. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. ... Traditionally, inorganic compounds are considered to be of mineral, not biological, origin. ... An organometallic compound is partially characterized by the presence of one or more metal-carbon bonds, in which the carbon involved would, apart from the metal-carbon bond, be otherwise considered a part of an organic compound. ...


Compounds in which components share electrons are known as covalent compounds. Compounds consisting of oppositely charged ions are known as ionic compounds, or salts. Covalent redirects here. ... This article is about the electrically charged particle. ... Electron configurations of lithium and fluorine. ... For other uses, see Salt (disambiguation). ...


In organic chemistry, there can be more than one chemical compound with the same composition and molecular weight. Generally, these are called isomers. Isomers usually have substantially different chemical properties, may be isolated and do not spontaneously convert to each other. A common example is glucose vs. fructose. The former is an aldehyde, the latter is a ketone. Their interconversion requires either enzymatic or acid-base catalysis. However, there are also tautomers, where isomerization occurs spontaneously, such that a pure substance cannot be isolated into its tautomers. A common example is glucose, which has open-chain and ring forms. One cannot manufacture pure open-chain glucose because glucose spontaneously cyclizes to the hemiacetal form. In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of chemical bonds between atoms, but in which the atoms are arranged differently (analogous to a chemical anagram). ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... Fructose (or levulose) is a simple sugar (monosaccharide) found in many foods and is one of the three most important blood sugars along with glucose and galactose. ... An aldehyde. ... Ketone group A ketone (pronounced as key tone) is either the functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms or a chemical compound that contains this functional group. ... Glucose Isomerase is an enzyme (EC 5. ... The Lobry-de Bruyn-van Ekenstein transformation also known as the Lobry-de Bruyn-van-Alberda-van-Ekenstein transformation is a base catalyzed Aldose-Ketose-Isomerization in carbohydrate chemistry [1] . A typical rearrangement reaction is that between glyceraldehyde and dihydroxyacetone in a chemical equilibrium. ... Tautomers are organic compounds that are interconvertible by a chemical reaction called tautomerization. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... A hemiacetal is a functional group or compound containing the function group in the form of: where R and R are any carbon backbones. ...

See also: list of organic compounds and list of inorganic compounds

This page aims to list well-known organic compounds, including organometallic compounds, to stimulate the creation of Wikipedia articles. ... This page aims to list well-known inorganic compounds, including organometallic compounds, to stimulate the creation of Wikipedia articles. ...

Substances versus mixtures

Main article: Mixture

All matter consists of various elements and chemical compounds, but these are often intimately mixed together. Mixtures contain more than one chemical substance, and they do not have a fixed composition. In principle, they can be separated into the component substances by purely mechanical processes. Butter, soil and wood are common examples of mixtures. In chemistry, a mixture is a substance made by combining two or more different materials in such a way that no chemical reaction occurs. ... For other uses, see Mechanic (disambiguation). ... For other uses, see Butter (disambiguation). ... Loess field in Germany Surface-water-gley developed in glacial till, Northern Ireland Soil is a complex mixture of materials, principally ground up rock and water. ... For other uses, see Wood (disambiguation). ...


Grey iron metal and yellow sulfur are both chemical elements, and they can be mixed together in any ratio to form a yellow-grey mixture. No chemical process occurs, and the material can be identified as a mixture by the fact that the sulfur and the iron can be separated by a mechanical process, such as using a magnet to attract the iron away from the sulfur. This article is about the chemical element. ... For other uses, see Magnet (disambiguation). ...


In contrast, if iron and sulfur are heated together in a certain ratio (56 grams (1 mol) of iron to 32 grams (1 mol) of sulfur), a chemical reaction takes place and a new substance is formed, the compound iron(II) sulfide, with chemical formula FeS. The resulting compound has all the properties of a chemical substance and is not a mixture. Iron(II) sulfide has its own distinct properties such as melting point and solubility, and the two elements cannot be separated using normal mechanical processes; a magnet will be unable to recover the iron, since there is no metallic iron present in the compound.Ion plus sodium choloride=a new form of metal this is ovious isnt it? BIC pen cap, about 1 gram. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... Iron(II) sulfide is a chemical compound with the formula FeS. In practice, iron sulfides are often non-stoichiometric. ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ... Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ...


Chemicals versus Chemical substances

While the term chemical substance is a somewhat technical term used most often by professional chemists, the word chemical[8] is more widely used in the pharmaceutical industry, government and society in general. Thus the word chemical includes a much wider class of substances that includes many mixtures of chemical substances that often find application in many vocations [9]; and is most commonly used only for artificial or processed substances, such as the products of the chemical industry. Pharmacology (in Greek: pharmacon is drug, and logos is science) is the study of how chemical substances interfere with living systems. ... The chemical industry comprises the companies that produce industrial chemicals. ...


Naming and Indexing

Every chemical substance has one or more systematic names, usually named according to the IUPAC rules for naming. An alternative system is used by the Chemical Abstracts Service (CAS) There are millions of possible objects that can be described in science, too many to create common names for every one. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... Chemical Abstracts Service (CAS) is a division of the American Chemical Society, and produces Chemical Abstracts, and related products. ...


Many compounds are also known by their more common, simpler names, many of which predate the systematic name. For example, the long-known sugar glucose is now systematically named 6-(hydroxymethyl)oxane-2,3,4,5-tetrol. Natural products and pharmaceuticals are also given simpler names, for example the mild pain-killer Naproxen is the more common name for the chemical compound (S)-6-methoxy-α-methyl-2-naphthaleneacetic acid. This article is about sugar as food and as an important and widely traded commodity. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... It has been suggested that this article or section be merged into natural product. ... Pharmacology (in Greek: pharmacon is drug, and logos is science) is the study of how chemical substances interfere with living systems. ... Naproxen (INN) (IPA: ) is a non-steroidal anti-inflammatory drug (NSAID) commonly used for the reduction of mild to moderate pain, fever, inflammation and stiffness caused by conditions such as osteoarthritis, rheumatoid arthritis, psoriatic arthritis, gout, ankylosing spondylitis, injury (like fractures), menstrual cramps, tendonitis, bursitis, and the treatment of primary...


Chemists frequently refer to chemical compounds using chemical formulae or molecular structure of the compound. There has been a phenomenal growth in the number of chemical compounds being synthesized (or isolated), and then reported in the scientific literature by professional chemists around the world [10]. An enormous number of chemical compounds are possible through the chemical combination of the known chemical elements. At the last count, about thirty million chemical compounds are known.[11]. The names of many of these compounds are often nontrivial and hence not very easy to remember or cite accurately. Also it is difficult to keep the track of them in the literature. Several international organizations like the IUPAC and the Chemical Abstract Service (CAS) have intiated steps to make such tasks easier. CAS that provides the abstracting services of the chemical literature, provides a numerical identifier, known as CAS registry number to each chemical substance that has been reported in the chemical literature (such as chemistry journals and patents). This information is compiled as a database and is popularly known as the Chemical substances index. Other computer-friendly systems that have been developed for substance information, are: SMILES and the International Chemical Identifier or InChI. A chemist pours from a round-bottom flask. ... Look up chemical compound in Wiktionary, the free dictionary. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Geometry of the water molecule Molecules have fixed equilibrium geometries--bond lengths and angles--that are dictated by the laws of quantum mechanics. ... Scientific literature is the totality of publications that report original empirical and theoretical work in the sciences and social sciences. ... The International Union of Pure and Applied Chemistry (IUPAC) is an international non-governmental organization devoted to the advancement of chemistry. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... There are very many scientific journals in chemistry containing original research, or reviews of other publications, or both. ... For other uses, see Patent (disambiguation). ... This article is about computing. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ... The IUPAC International Chemical Identifier (InChI), developed by IUPAC and NIST, is a digital equivalent of the IUPAC name for any particular covalent compound. ...

Identification of a typical chemical substance
Common name Systematic name Chemical formula Chemical structure CAS registry number InChI
alcohol, or
ethyl alcohol
ethanol C2H5OH
[64-17-5] 1/C2H6O/c1-2-3/h3H,2H2,1H3

IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Chemical structure refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... The IUPAC International Chemical Identifier (InChI), developed by IUPAC and NIST, is a digital equivalent of the IUPAC name for any particular covalent compound. ... Image File history File links Download high resolution version (871x379, 6 KB) Summary Description: Structural formula of en:Ethanol (C2H5OH). ...

Isolation, purification, characterisation and identification

Often a pure substance needs to be isolated from a mixture, for example from a natural source (where a sample often contains numerous chemical substances) or after a chemical reaction (which often give mixtures of chemical substances). In chemistry, a mixture is a substance made by combining two or more different materials in such a way that no chemical reaction occurs. ... This article is about the physical universe. ... For other uses, see Chemical reaction (disambiguation). ...


References and notes

  1. ^ Hill, J. W.; Petrucci, R. H.; McCreary, T. W.; Perry, S. S. General Chemistry, 4th ed., p37, Pearson Prentice Hall, Upper Saddle River, New Jersey, 2005.
  2. ^ http://dbhs.wvusd.k12.ca.us/webdocs/AtomicStructure/LawofDefiniteProportion.html
  3. ^ Hill, J. W.; Petrucci, R. H.; McCreary, T. W.; Perry, S. S. General Chemistry, 4th ed., p5, Pearson Prentice Hall, Upper Saddle River, New Jersey, 2005
  4. ^ http://www.diracdelta.co.uk/science/source/p/u/pure%20substance/source.html
  5. ^ http://www.cas.org/ASSETS/58D34DD3892142D18F5C3B0A004D3A0C/indexguideapp.pdf
  6. ^ Hill, J. W.; Petrucci, R. H.; McCreary, T. W.; Perry, S. S. General Chemistry, 4th ed., pp45-46, Pearson Prentice Hall, Upper Saddle River, New Jersey, 2005.
  7. ^ The boundary between metalloids and non-metals is imprecise, as explained in the previous reference.
  8. ^ What is a chemical
  9. ^ http://www.bfr.bund.de/cd/569
  10. ^ http://www.rz.uni-karlsruhe.de/~ed01/Jslit/eduquim.htm
  11. ^ Chemical Abstracts substance count

  Results from FactBites:
 
chemical substance: Information from Answers.com (0 words)
The concept of a chemical substance became firmly established in the late eighteenth century after work by the chemist Joseph Proust on the composition of some pure chemical compounds such as basic copper carbonate.
No chemical process occurs, and the material can be identified as a mixture by the fact that the sulfur and the iron can be separated by a mechanical process, such as using a magnet to attract the iron away from the sulfur.
Often a chemical substance needs to be isolated from a mixture, for example from a natural source (where a sample often contains numerous chemical substances) or after a chemical reaction (which often give mixtures of chemical substances).
  More results at FactBites »

 
 

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