tag:blogger.com,1999:blog-11776097921268611672012-02-16T07:08:46.826-08:00Almost all the posts are from http://en.wikipedia.orgLindanoreply@blogger.comBlogger1841100tag:blogger.com,1999:blog-1177609792126861167.post-56002800330368915032008-10-03T08:23:00.000-07:002008-10-03T08:28:20.922-07:00

Bone char, also known as bone black or animal charcoal, is a granular material produced by charring animal bones: the bones are heated to high temperatures (in the range of 400 to 500 °C) in an oxygen-depleted atmosphere to control the quality of the product as related to its adsorption capacity for applications such as defluoridation of water and removal of heavy metals from aqueous

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-24574525931319011432008-10-03T08:19:00.000-07:002008-10-03T08:23:39.420-07:00

In chemistry, bond strength is measured between two atoms joined in a chemical bond . It is the degree to which each atom linked to a central atom contributes to the valency of this central atom. Bond strength is intimately linked to bond order.Bond strength can be quantified by:bond energy: requires lengthy calculations, even for the simplest bonds. bond dissociation energyAnother criterion of

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-59709073504706915022008-10-03T08:16:00.000-07:002008-10-03T08:19:35.139-07:00

In chemistry, polarity refers to the dipole-dipole intermolecular forces between the slightly positively-charged end of one molecule to the negative end of another or the same molecule. Molecular polarity is dependent on the difference in electronegativity between atoms in a compound and the asymmetry of the compound's structure. For example, water is thought to be polar because of the unequal

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-10498077174870715482008-09-24T11:07:00.000-07:002008-09-24T11:10:31.191-07:00

In molecular geometry, bond length or bond distance is the average distance between nuclei of two bonded atoms in a molecule.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-66661286530292802542008-09-20T19:28:00.000-07:002008-09-20T19:34:38.580-07:00

In chemistry, bond energy (E) is a measure of bond strength in a chemical bond. For example the carbon-hydrogen bond energy in methane E(C–H) is the enthalpy change involved with breaking up one molecule of methane into a carbon atom and 4 hydrogen radicals divided by 4. Bond energy (E) should not be confused with bond dissociation energy.Another example: an O–H bond of a water molecule (H–O–H)

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-76150297299697230792008-09-20T09:17:00.000-07:002008-09-20T14:04:49.304-07:00

In chemistry, bond dissociation energy, D0 or BDE, is one measure of the bond strength in a chemical bond. It is defined as the standard enthalpy change when a bond is cleaved by homolysis, with reactants and products of the homolysis reaction at 0 K (absolute zero). For instance, the bond dissociation energy for one of the C-H bonds in ethane (C2H6) is defined by the process:CH3CH2-H → CH3CH2 +

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-496802213273837892008-09-20T09:12:00.000-07:002008-09-20T09:17:42.830-07:00

Molecular geometry or molecular structure is the three-dimensional arrangement of the atoms that constitute a molecule, inferred from the spectroscopic studies of the compound. It determines several properties of a substance including its reactivity, polarity, phase of matter, color, magnetism, and biological activity . Molecular geometries are best determined at temperatures close to absolute

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-19355556444808634262008-09-20T09:08:00.000-07:002008-09-20T09:12:14.641-07:00

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. The explanation of the attractive forces is a complex area that is described by the laws of quantum electrodynamics. In practice, however, chemists usually rely on quantum theory or qualitative descriptions

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-45462005357127926422008-09-20T08:38:00.000-07:002008-09-20T09:08:06.918-07:00

The boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid. A liquid in a vacuum environment has a lower boiling point than when the liquid is at atmospheric pressure. A liquid in a high pressure environment has a higher boiling point than when the liquid is at atmospheric pressure. In other words, the

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-2677214715582098722008-09-20T08:31:00.000-07:002008-09-20T08:38:02.519-07:00

Blood is a specialized bodily fluid (technically a tissue).In vertebrates it is composed of blood cells suspended in a liquid called blood plasma. Plasma, which comprises 55% of blood fluid, is mostly water (90% by volume), and contains dissolved proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), platelets and blood cells

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-55548460980306947962008-09-20T08:01:00.000-07:002008-09-20T08:29:21.815-07:00

Bivalent (chemistry): two or more atoms bound together as a single unit and forming part of a moleculeAn atom which can form two covalent bonds with other molecules (such as oxygen) is said to be bivalent, possessing a valency of two.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-49254050016967265252008-09-20T07:56:00.000-07:002008-09-20T08:01:43.242-07:00

The Biuret reagent is made of potassium hydroxide (KOH) and copper (II) sulfate (CuSO4), together with potassium sodium tartrate (KNaC4H4O6·4H2O). The blue reagent turns violet in the presence of proteins, and changes to pink when combined with short-chain polypeptides. The potassium hydroxide does not participate in the reaction at all, but is merely there to provide an alkaline medium so that

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-21101529106031709912008-09-20T07:53:00.000-07:002008-09-20T07:56:31.311-07:00

Bituminous coal is a relatively soft coal containing a tarlike substance called bitumen. It is of higher quality than lignite coal but poorer quality than anthracite coal.Bituminous coal is an organic sedimentary rock formed by diagenetic and submetamorphic compression of peat bog material.Bituminous coal has been compressed and heated so that its primary constituents are the macerals vitrinite,

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-60456637535203328552008-09-20T07:49:00.002-07:002008-09-20T07:53:46.131-07:00

Bisphenol A, commonly abbreviated as BPA, is an organic compound with two phenol functional groups. It is a difunctional building block of several important polymers and polymer additives. With an annual production of 2–3 million tonnes, it is an important monomer in the production of polycarbonate.Suspected of being hazardous to humans since the 1930s, concerns about the use of Bisphenol A in

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-58457547177902611772008-09-20T07:49:00.001-07:002008-09-20T07:49:47.336-07:00

Bis-, a prefix meaning "two" in some contexts of chemical nomenclature

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-53750001016684972882008-09-20T07:43:00.000-07:002008-09-20T07:49:08.732-07:00

Biotin, also known as vitamin H or B7, has the chemical formula C10H16N2O3S (Biotin; Coenzyme R, Biopeiderm), is a water-soluble B-complex vitamin which is composed of an ureido (tetrahydroimidizalone) ring fused with a tetrahydrothiophene ring. A valeric acid substituent is attached to one of the carbon atoms of the tetrahydrothiophene ring. Biotin is a cofactor in the metabolism of fatty acids

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-8348559804029132702008-09-20T07:42:00.000-07:002008-09-20T07:43:10.490-07:00

The development of biomaterials is not a new area of science, having existed for around half a century. The study of biomaterials is called biomaterial science. It is an exciting field of science, having experienced steady and strong growth over its history with companies such as Smith and Nephew investing large amounts of money in new products. Biomaterials science encompasses elements of

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-59100111732466133292008-09-20T07:40:00.000-07:002008-09-20T07:42:01.308-07:00

Biochemical Oxygen Demand or Biological Oxygen Demand (BOD) is a chemical procedure for determining how fast biological organisms use up oxygen in a body of water. It is used in water quality management and assessment, ecology and environmental science. BOD is not an accurate quantitative test, although it could be considered as an indication of the quality of a water source.BOD can be used as a

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-36088409040013901892008-09-20T07:37:00.000-07:002008-09-20T07:40:13.113-07:00

Biochemistry is the study of the chemical processes in living organisms. It deals with the structure and function of cellular components, such as proteins, carbohydrates, lipids, nucleic acids, and other biomolecules.Although there are a vast number of different biomolecules, many are complex and large molecules (called polymers) that are composed of similar repeating subunits (called monomers).

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-80057724613279107942008-09-20T07:36:00.000-07:002008-09-20T07:37:33.895-07:00

Biocatalysis can be defined as utilization of natural catalysts, such as protein enzymes, to perform chemical transformations on organic compounds. Both enzymes that have been more or less isolated or enzymes still residing inside living cells are employed for this task.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-1854200475083428912008-09-20T07:34:00.000-07:002008-09-20T07:36:42.210-07:00

Bioassay is a shorthand commonly used term for biological assay and is a type of scientific experiment.Bioassays are typically conducted to measure the effects of a substance on a living organism. Bioassays may be qualitative or quantitative. Qualitative bioassays are used for assessing the physical effects of a substance that may not be quantified, such as abnormal development or deformity.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-86060267184428974372008-09-20T07:31:00.000-07:002008-09-20T07:33:32.139-07:00

A prefix is a type of affix attached to a stem which modifies the meaning of that stem.The word "prefix" is itself made up of the stem fix (meaning "attach" in this case), and the prefix pre-, meaning "before", both of which are derived from Latin roots.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-6641497803124916372008-09-20T07:07:00.000-07:002008-09-20T07:30:03.796-07:00

A binary compound is a compound that contains two different elements, such as NaCl (salt or sodium chloride). Another example is NaF (sodium fluoride). One other example is Magnesium Oxide (MgO).

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-41988416119901316132008-09-04T08:22:00.000-07:002008-09-04T08:28:54.800-07:00

Bile or gall is a bitter yellow or green alkaline fluid secreted by hepatocytes from the liver of most vertebrates. In many species, bile is stored in the gallbladder between meals and upon eating is discharged into the duodenum where the bile aids the process of digestion of lipids.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-47126003269813385202008-09-04T07:59:00.000-07:002008-09-04T08:22:31.488-07:00

Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei such as potassium-40. The beta particles emitted are a form of ionizing radiation also known as beta rays. The production of beta particles is termed beta decay. They are designated by the Greek letter beta (β). There are two forms of beta decay, β− and β+, which respectively give rise

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-52769516867921869672008-09-04T07:19:00.000-07:002008-09-04T07:55:50.013-07:00

In organic chemistry, benzyl is the term used to describe the substituent or molecular fragment possessing the structure C6H5CH2-. The abbreviation "Bn" is frequently used to denote benzyl moieties in nomenclature and structural depictions of chemical compounds. For example, benzyl alcohol can be represented as BnOH. This abbreviation is not to be confused with "Bz", which is the abbreviation

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-19245543177693816042008-09-04T07:15:00.000-07:002008-09-04T07:18:49.241-07:00

In organic chemistry, benzoyl is the acyl of benzoic acid, with structure C6H5CO-. It should not be confused with benzyl, which is the radical or ion formed from the removal of one of the methyl hydrogens of toluene (methylbenzene). Whereas a benzyl substituent is commonly abbreviated "Bn", a benzoyl group is in contrast given the symbol "Bz".

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-51853266734410189432008-09-04T07:12:00.000-07:002008-09-04T07:15:08.836-07:00

The Benzoin condensation is a condensation reaction between two aromatic aldehydes, especially benzaldehyde, that is catalyzed by cyanide anion. The reaction product is an aromatic acyloin with benzoin as the parent compound . An early version of the reaction was developed in 1832 by Justus von Leibig and Friederich Woehler during their research on oil of bitter almond. The catalytic version of

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-31492389880564783022008-09-04T07:10:00.000-07:002008-09-04T07:12:07.583-07:00

Benzoic acid, C7H6O2 (or C6H5COOH), is a colorless crystalline solid and the simplest aromatic carboxylic acid. The name derived from gum benzoin, which was for a long time the only source for benzoic acid. This weak acid and its salts are used as a food preservative. Benzoic acid is an important precursor for the synthesis of many other organic substances.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-3208425910668750912008-09-03T08:21:00.000-07:002008-09-03T08:49:44.564-07:00

Benzidine is the trivial name for 4,4'-diaminobiphenyl, a carcinogenic aromatic amine which has been used as part of a test for cyanide and also in the synthesis of dyes. It has been linked to bladder cancer and pancreatic cancer.In common with benzidine some other aromatic amines such as 2-aminonaphthalene have been withdrawn from use in almost all industries because they are so

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-59522218790283666032008-09-03T08:11:00.000-07:002008-09-03T08:18:38.558-07:00

Benzene, or benzol, is an organic chemical compound and a known carcinogen with the molecular formula C6H6. It is sometimes abbreviated Ph–H. Benzene is a colorless and highly flammable liquid with a sweet smell and a relatively high melting point. Because it is a known carcinogen, its use as an additive in gasoline is now limited, but it is an important industrial solvent and precursor in the

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-24954351051775634582008-09-03T08:03:00.000-07:002008-09-03T08:11:26.303-07:00

Benzaldehyde (C6H5CHO) is a chemical compound consisting of a benzene ring with an aldehyde substituent. It is the simplest representative of the aromatic aldehydes and one of the most industrially used members of this family of compounds. At room temperature it is a colorless liquid with a characteristic and pleasant almond-like odor: benzaldehyde is an important component of the scent of

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-10903155187799088082008-09-03T08:00:00.000-07:002008-09-03T08:03:44.906-07:00

Bentonite is an absorbent aluminium phyllosilicate generally impure clay consisting mostly of montmorillonite. There are a few types of bentonites and their names depend on the dominant elements, such as K, Na, Ca, and Al. As noted in several places in the geologic literature, there are some nomenclatorial problems with the classification of bentonite clays. Bentonite usually forms from

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-30698461280706872642008-09-03T07:54:00.000-07:002008-09-03T07:59:14.280-07:00

Benedict's reagent (also called Benedict's solution or Benedict's test) is a chemical reagent named after an American chemist, Stanley Rossiter Benedict.Benedict's reagent is used as a test for the presence of all monosaccharides, and generally also reducing sugars. These include glucose, galactose, mannose, lactose and maltose. Even more generally, Benedict's test will detect the presence of

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-4333312929568605452008-09-03T07:51:00.000-07:002008-09-03T08:00:03.041-07:00

Beeswax is a natural wax produced in the bee hive of honey bees of the genus Apis. Beeswax is produced by young worker bees between 12 and 17 days old in the form of thin scales secreted by glands on the ventral surface of the abdomen. Worker bees have eight wax-producing mirror glands on the inner sides of the sternites (the ventral shield or plate of each segment of the body) on abdominal

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-32798626769484761872008-09-03T07:48:00.000-07:002008-09-03T07:51:15.530-07:00

The B vitamins are eight water-soluble vitamins that play important roles in cell metabolism. Historically, the B vitamins were once thought to be a single vitamin, referred to as vitamin B (much like how people refer to vitamin C or vitamin D). Later research showed that they are chemically distinct vitamins that often coexist in the same foods. Supplements containing all eight are generally

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-86958346060238162752008-09-03T07:45:00.000-07:002008-09-03T07:48:06.559-07:00

Bauxite is the most important aluminium ore. It consists largely of the minerals gibbsite Al(OH)3, boehmite γ-AlO(OH), and diaspore α-AlO(OH), together with the iron oxides goethite and hematite, the clay mineral kaolinite and small amounts of anatase TiO2. It was named after the village Les Baux in southern France, where it was first discovered in 1821 by the geologist Pierre Berthier.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-57743256374606828222008-09-03T07:42:00.000-07:002008-09-03T07:45:00.808-07:00

In electronics, a battery is a combination of two or more electrochemical cells which store chemical energy and make it available as electrical energy. Since its invention in 1800 by Alessandro Volta, the battery has become a common power source for many household and industrial applications, becoming a multibillion-dollar industry.The name "battery" was coined by Benjamin Franklin for an

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-41923626310955491002008-09-03T07:40:00.000-07:002008-09-03T07:41:52.056-07:00

In chemistry, a base is most commonly thought of as an aqueous substance that can accept protons. This refers to the Brønsted-Lowry theory of acids and bases. Alternate definitions of bases include electron pair donors (Lewis), as sources of hydroxide anions (Arrhenius) and can be (commonly) thought of as any chemical compound that, when dissolved in water, gives a solution with a pH higher than

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-34645248091511441032008-09-03T07:38:00.000-07:002008-09-03T07:39:42.808-07:00

Basal metabolic rate (BMR) is the amount of energy expended while at rest in a neutrally temperate environment, in the post-absorptive state (meaning that the digestive system is inactive, which requires about twelve hours of fasting in humans). The release of energy in this state is sufficient only for the functioning of the vital organs, such as the heart, lungs, brain and the rest of the

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-2165952001524302062008-09-03T07:32:00.000-07:002008-09-03T07:38:12.709-07:00

Isoamyl acetate, also known as isopentyl acetate, is an organic compound that is the ester formed from isoamyl alcohol and acetic acid. It is a clear colorless liquid that is only slightly soluble in water, but very soluble in most organic solvents.Isoamyl acetate has a strong odor (similar to juicy fruit) which is also described as similar to both banana and pear. Banana oil is a term that is

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-6691689711462224102008-09-02T08:39:00.000-07:002008-09-02T08:44:22.612-07:00

Baking powder is a dry chemical leavening agent used in cooking, mainly baking. Traditional baking powder was composed of a mixture of tartaric acid and bicarbonate of soda (baking soda), a quantity of flour or cornstarch usually being added to reduce the strength . When dissolved in water the acid and bicarbonate react and emit carbon dioxide gas which expands, producing bubbles to leaven the

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-21678423662385898912008-09-02T08:38:00.000-07:002008-09-02T08:39:15.672-07:00

Baeyer strain theory or strain theory explains specific behaviour of chemical compounds in terms of bond angle strain.It was proposed by Adolf von Baeyer in 1885 to account for the unusual chemical reactivity in ring opening reactions of cyclopropanes and cyclobutanes where this angle strain is relieved.On ring strain he noted in 1885:

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-42466004910065066242008-09-02T08:31:00.000-07:002008-09-02T08:37:19.830-07:00

A bacteriophage (from 'bacteria' and Greek φάγειν phagein "to eat") is any one of a number of viruses that infect bacteria. The term is commonly used in its shortened form, phage.Typically, bacteriophages consist of an outer protein hull enclosing genetic material. The genetic material can be ssRNA (single stranded RNA), dsRNA, ssDNA, or dsDNA between 5 and 500 kilo base pairs long with either

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-69671922594668972622008-09-02T08:20:00.000-07:002008-09-02T08:26:27.414-07:00

The Bacteria [bækˈtɪr.i.ə] (singular: bacterium) are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. (The name comes from the Greek baktērion, meaning small staff.) Bacteria are ubiquitous in every habitat on Earth, growing in soil, acidic hot springs, radioactive waste, water, and

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-31626424805671865822008-09-02T08:17:00.000-07:002008-09-02T08:30:59.067-07:00

In organic chemistry, the backbone chain of a polymer is the series of covalently-bonded atoms that together create the continuous chain of the molecule.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-31315335674943278602008-09-02T08:13:00.000-07:002008-09-02T08:15:27.423-07:00

Azo compounds are compounds bearing the functional group R-N=N-R', in which R and R' can be either aryl or alkyl. The N=N group is called an azo group, although the parent compound, HNNH, is called diimide. The more stable derivatives contain two aryl groups. The name azo comes from azote, the French name of nitrogen that is derived from the Greek a (not) + zoe (to live).

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-21224931342542747052008-09-02T08:12:00.000-07:002008-09-02T08:28:45.401-07:00

An azeotrope is a mixture of two or more pure compounds (chemicals) in such a ratio that its composition cannot be changed by simple distillation. This is because when an azeotrope is boiled, the resulting vapor has the same ratio of constituents as the original mixture of liquids. As the composition is unchanged by boiling, azeotropes are also known as constant boiling mixtures (especially in

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-48260653326525632842008-09-02T08:08:00.000-07:002008-09-02T08:10:58.047-07:00

The Avogadro constant (symbols: L, NA), also called the Avogadro number, is the number of atoms in exactly 12 grams of 12C. A mole is defined as this number of "entities" (usually, atoms or molecules) of any material. The currently accepted value for this number is:The value of Avogadro's constant was first indicated by Johann Josef Loschmidt who, in 1865, computed the number of particles in one

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-40280541908881071752008-09-02T08:00:00.000-07:002008-09-02T08:08:16.324-07:00

Auxins are a class of plant growth substance (often called phytohormone or plant hormone). Auxins play an essential role in coordination of many growth and behavioral processes in the plant life cycle.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-85063254506202645022008-09-02T07:54:00.000-07:002008-09-02T07:59:57.509-07:00

Autoxidation is any oxidation that occurs in open air or in presence of oxygen and/or UV radiation and forms peroxides and hydroperoxides. A classic example of autoxidation is that of simple ethers like diethyl ether, whose peroxides can be dangerously explosive. It can be considered to be a slow, flameless combustion of materials by reaction with oxygen. Autoxidation is important because it is a

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-79819114382138272652008-09-02T07:51:00.000-07:002008-09-02T07:54:36.095-07:00

Atropine is a tropane alkaloid extracted from deadly nightshade (Atropa belladonna), jimsonweed (Datura stramonium) and other plants of the family Solanaceae. It is a secondary metabolite of these plants and serves as a drug with a wide variety of effects. It is a competitive antagonist for the muscarinic acetylcholine receptor. It is classified as an anticholinergic drug. Being potentially

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-36703901941233550772008-09-02T07:42:00.000-07:002008-09-02T07:47:06.670-07:00

Adenosine-5'-triphosphate (ATP) is a multifunctional nucleotide that is most important as a "molecular currency" of intracellular energy transfer. In this role, ATP transports chemical energy within cells for metabolism. It is produced as an energy source during the processes of photosynthesis and cellular respiration and consumed by many enzymes and a multitude of cellular processes including

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-78285526433610974682008-09-02T07:37:00.000-07:002008-09-02T07:42:10.139-07:00

The atomic mass (ma) is the mass of an atom, most often expressed in unified atomic mass units. The atomic mass may be considered to be the total mass of protons, neutrons and electrons in a single atom (when the atom is motionless). The atomic mass is sometimes incorrectly used as a synonym of relative atomic mass, average atomic mass and atomic weight; however, these differ subtly from the

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-31621515041682269122008-09-02T07:36:00.000-07:002008-09-02T07:37:47.120-07:00

In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element. In an atom of neutral charge, atomic number is equal to the number of electrons.The atomic number Z should not be confused with the mass number A, which is

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-85451453157547162392008-09-02T07:32:00.000-07:002008-09-02T07:36:15.825-07:00

The unified atomic mass unit (u), or dalton (Da) or, sometimes, universal mass unit, is a unit of mass used to express atomic and molecular masses. It is the approximate mass of a hydrogen atom, a proton, or a neutron.The precise definition is that it is one twelfth of the mass of an unbound atom of carbon-12 (12C) at rest and in its ground state.1 u = 1/NA gram = 1/ (1000 NA) kg (where NA is

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-19138862865864554612008-09-02T07:26:00.000-07:002008-09-03T09:08:46.753-07:00

The atom is the smallest unit of an element that retains the chemical properties of that element. An atom has an electron cloud consisting of negatively charged electrons surrounding a dense nucleus. The nucleus contains positively charged protons and electrically neutral neutrons. When the number of protons in the nucleus equals the number of electrons, the atom is electrically neutral;

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-39514197936242608482008-09-01T09:18:00.000-07:002008-09-01T09:23:05.395-07:00

An atmosphere (from Greek ατμός - atmos, "vapor" + σφαίρα - sphaira, "sphere") is a layer of gases that may surround a material body of sufficient mass, by the gravity of the body, and are retained for a longer duration if gravity is high and the atmosphere's temperature is low. Some planets consist mainly of various gases, and therefore have very deep atmospheres (see gas giants).The term

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-80979185374162067282008-09-01T09:14:00.000-07:002008-09-01T09:16:50.442-07:00

Atherosclerosis is a disease affecting arterial blood vessels. It is a chronic inflammatory response in the walls of arteries, in large part due to the accumulation of macrophage white blood cells and promoted by low density (especially small particle) lipoproteins (plasma proteins that carry cholesterol and triglycerides) without adequate removal of fats and cholesterol from the macrophages by

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-44531735427313867352008-09-01T09:07:00.000-07:002008-09-01T09:08:28.138-07:00

Certain molecules are chiral; that is, they cannot be superposed upon their mirror image.Some sugars are chiral: glucose (also called dextrose) and fructose (sometimes called levulose or invert sugar) are chiral isomers of the same molecule, C6H12O6. The word invert comes from the way that sugar syrups rotate plane-polarized light. A sucrose or glucose solution rotates the plane of polarization

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-18069548054656241702008-09-01T09:06:00.000-07:002008-09-01T09:12:12.344-07:00

An asymmetric carbon is a carbon atom that is attached to four different atoms or four different groups of atoms. The duality that this produces allows for different structural compositions of carbon based molecules (e.g. sugars). By taking the number of asymmetric carbon atoms, one can calculate the possible number of enantiomers for that molecule.Maximum number of isomers = 2n where n = the

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-70660045466437373472008-09-01T09:03:00.003-07:002008-09-01T09:05:29.022-07:00

Astatine is a radioactive chemical element with the symbol At and atomic number 85. It is the heaviest of the discovered halogens.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-57677576144579324482008-09-01T09:00:00.000-07:002008-09-01T09:01:24.486-07:00

An assay is a procedure where a property or concentration of an analyte is measured.There are numerous types of assays, such as an antigen capture assay, bioassay, competitive protein binding assay, crude oil assay, four-point assay, immunoassay, microbiological assay, stem cell assay, and many others, including concentration assays.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-39152857491322966792008-09-01T08:53:00.000-07:002008-09-01T08:58:27.680-07:00

Aspirin, or acetylsalicylic acid is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It also has an antiplatelet or "anti-clotting" effect and is used in long-term, low doses to prevent heart attacks, strokes and blood clot formation in people at high risk for developing blood clots.It has

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-20834602841021985202008-09-01T08:49:00.000-07:002008-09-01T08:53:14.536-07:00

Asphalt (ˈæs.fɒlt (help·info)) is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits sometimes termed asphaltum. It is most commonly modeled as a colloid, with asphaltenes as the dispersed phase and maltenes as the continuous phase (though there is some disagreement amongst chemists regarding its structure). In U.S.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-88326075833331478662008-09-01T08:45:00.000-07:002008-09-01T08:49:12.811-07:00

Ash is one of the components in the proximate analysis of biological materials, consisting mainly of salty, inorganic constituents. It includes metal salts which are important for processes requiring ions such as Na+ (Sodium), K+ (Potassium), Ca2+ (Calcium). It also includes trace minerals which are required for unique molecules, such as chlorophyll and hemoglobin.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-60518796359636005892008-09-01T08:42:00.000-07:002008-09-01T08:45:54.222-07:00

Ascorbic acid is a sugar acid with antioxidant properties. Its appearance is white to light-yellow crystals or powder. It is water-soluble. The L-enantiomer of ascorbic acid is commonly known as vitamin C. The name is derived from the alpha privative a- (meaning no) and scorbuticus (scurvy), the disease caused by a deficiency of vitamin C. In 1937 the Nobel Prize for chemistry was awarded to

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-27923170602481140552008-09-01T08:37:00.000-07:002008-09-01T08:42:39.032-07:00

Asbestos is a group of minerals with long, thin fibrous crystals. The word "asbestos" is derived from a Greek adjective meaning inextinguishable. The Greeks termed asbestos the "miracle mineral" because of its soft and pliant properties, as well as its ability to withstand heat. Asbestos became increasingly popular among manufacturers and builders in the late 19th century due to its resistance to

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-25755451311359958752008-09-01T08:33:00.000-07:002008-09-01T08:37:34.665-07:00

In the context of organic molecules, aryl refers to any functional group or substituent derived from a simple aromatic ring, may it be phenyl, thiophenyl, indolyl, etc (see IUPAC nomenclature). "Aryl" is used for the sake of abbreviation or generalization.A simple aryl group is phenyl, C6H5; it is derived from benzene. The tolyl group, CH3C6H4, is derived from toluene (methylbenzene). The xylyl

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-45733949709497371722008-09-01T08:31:00.000-07:002008-09-01T08:33:32.839-07:00

Aromaticity is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. It can also be considered a manifestation of cyclic delocalization and of resonance.This is usually considered to be because electrons are free to cycle around circular arrangements of

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-81515818479193291582008-09-01T08:28:00.000-07:002008-09-01T08:31:21.591-07:00

An aromatic hydrocarbon (abbreviated as AH) or arene is a hydrocarbon, of which the molecular structure incorporates one or more planar sets of six carbon atoms that are connected by delocalised electrons numbering the same as if they consisted of alternating single and double covalent bonds. The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered,

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-46707340264460305852008-09-01T08:25:00.000-07:002008-09-01T08:28:11.558-07:00

Arachidonic acid (AA, sometimes ARA) is an omega-6 fatty acid 20:4(ω-6). It is the counterpart to the saturated arachidic acid found in peanut oil, (L. arachis – peanut.)

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-15909362699629559642008-09-01T08:23:00.000-07:002008-09-01T08:25:48.804-07:00

Aqua regia (Latin for royal water) is a highly corrosive, fuming yellow or red solution. The mixture is formed by freshly mixing concentrated nitric acid and concentrated hydrochloric acid, usually in a volumetric ratio of 1:3 respectively. It is one of the few reagents that dissolves gold and platinum. It was so named because it can dissolve the so-called royal, or noble metals, although

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-71857606677732624852008-09-01T08:20:00.000-07:002008-09-01T08:22:58.433-07:00

Antiseptics (from Greek αντί - anti, '"against" + σηπτικός - septikos, "putrefactive") are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction. They should generally be distinguished from antibiotics that destroy bacteria within the body, and from disinfectants, which destroy microorganisms found on non-living objects.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-28001810088424355702008-09-01T08:16:00.000-07:002008-09-01T08:20:32.656-07:00

Antisense molecules interact with complementary strands of nucleic acids, modifying expression of genes.Some regions within a double strand of DNA code for genes, which are usually instructions specifying the order of amino acids in a protein along with regulatory sequences, splicing sites, noncoding introns and other complicating details. For a cell to use this information, one strand of the DNA

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-8998245467150429762008-09-01T08:14:00.000-07:002008-09-01T08:15:30.545-07:00

An antimetabolite is a chemical with a similar structure to a substance (a metabolite) required for normal biochemical reactions, yet different enough to interfere with the normal functions of cells, including cell division.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-85121424203433416272008-09-01T08:10:00.000-07:002008-09-01T08:14:22.027-07:00

An antioxidant is a molecule capable of slowing or preventing the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent. Oxidation reactions can produce free radicals, which start chain reactions that damage cells. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-68204810879937457272008-09-01T08:06:00.000-07:002008-09-01T08:10:39.691-07:00

Antimony (IPA [æˈntɪməˌniː] (Received Pronunciation), /ˈæntɪmoʊni/ (US)) is a chemical element with the symbol Sb (Latin: stibium, meaning "mark") and atomic number 51. A metalloid, antimony has four allotropic forms. The stable form of antimony is a blue-white metalloid. Yellow and black antimony are unstable non-metals. Antimony is used in flame-proofing, paints, ceramics, enamels, a wide

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-10723865845010520372008-09-01T08:04:00.000-07:002008-09-01T08:06:46.181-07:00

Organolead compounds are chemical compounds containing a chemical bond between carbon and lead. Organolead chemistry is the corresponding science. The first organolead was hexaethyldilead synthesised in 1858. Sharing the same group with carbon, lead is tetravalent.Going down the carbon group the C–X (X = C, Si. Ge, Sn, Pb) bond becomes weaker and the bond length larger. The C–Pb bond in

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-64267475678858033802008-09-01T08:02:00.000-07:002008-09-01T08:03:54.534-07:00

A histamine antagonist is an agent which serves to inhibit the release or action of histamine. Antihistamine can be used to describe any histamine antagonist, but it is usually reserved for the classical antihistamines that act upon the H1 histamine receptor.Antihistamines are used as treatment for allergies. Allergies are caused by an excessive response of the body to allergens, materials that

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-31274676113828340392008-09-01T07:56:00.000-07:002008-09-01T08:01:43.480-07:00

An antigen (from antibody-generating) or immunogen [citation needed] is a substance that prompts the generation of antibodies and can cause an immune response. The word originated from the notion that they can stimulate antibody generation. We now know that the immune system does not consist of only antibodies. The modern definition encompasses all substances that can be recognized by the

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-40576757409174104942008-08-06T08:08:00.000-07:002008-08-06T08:15:29.988-07:00

Antifreeze is a cryoprotectant used in internal combustion engines, and for many other heat transfer applications, such as electronics cooling and chillers for HVAC. Compounds are added to water to reduce the freezing point of the mixture to below the lowest temperature that the system is likely to be exposed to, and to inhibit corrosion in cooling systems which often contain a range of

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-3881026264125148622008-08-06T08:01:00.000-07:002008-08-06T08:07:29.938-07:00

An anticodon is a unit made up of three nucleotides that correspond to the three bases of the codon on the mRNA. Each tRNA contains a specific anticodon triplet sequence that can base-pair to one or more codons for an amino acid. For example, one codon for lysine is AAA; the anticodon of a lysine tRNA might be UUU. Some anticodons can pair with more than one codon due to a phenomenon known as

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-25596957241583284382008-08-06T07:59:00.000-07:002008-08-06T08:00:29.983-07:00

An anticoagulant is a substance that prevents coagulation; that is, it stops blood from clotting. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders. Some chemical compounds are used in medical equipment, such as test tubes, blood transfusion bags, and renal dialysis equipment.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-58714848797243692402008-08-06T07:49:00.000-07:002008-08-06T07:58:27.605-07:00

An antichlor is a substance used to remove the excess of chlorine. Typical antichlors are sodium bisulfite and sodium thiosulfite. The antichlor is usually added right before the end of the bleaching process. It is mainly used on fiber, textiles, and paper pulp.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-71842574701111389092008-08-06T07:42:00.000-07:002008-08-06T07:49:09.412-07:00

Antibodies (also known as immunoglobulins) are gamma globulin proteins that are found in blood or other bodily fluids of vertebrates, and are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses. They are typically made of basic structural units - each with two large heavy chains and two small light chains - to form, for example, monomers with one

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-32097844791316753352008-08-06T07:13:00.000-07:002008-08-06T07:35:34.380-07:00

Testing the susceptibility of Staphylococcus aureus to antibiotics by the Kirby-Bauer disk diffusion method. Antibiotics diffuse out from antibiotic-containing disks and inhibit growth of S. aureus resulting in a zone of inhibition.The term antibiotic (from Greek αντί - anti, "against" + βιοτικός - biotikos, "fit for life") was coined by Selman Waksman in 1942, to refer to any substance produced

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-86930530743396726882008-08-05T01:42:00.000-07:002008-08-05T01:57:02.312-07:00

Anthraquinone (9,10-dioxoanthracene) is an aromatic organic compound. It is a derivative of anthracene. It has the appearance of yellow or light gray to gray-green solid crystalline powder.Its other names are 9,10-anthracenedione, anthradione, 9,10-anthrachinon, anthracene-9,10-quinone, 9,10-dihydro-9,10-dioxoanthracene, and trade names Hoelite, Morkit, Corbit, and others.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-362194528522334492008-08-05T01:24:00.000-07:002008-08-05T01:35:50.604-07:00

Anthracene is a solid polycyclic aromatic hydrocarbon consisting of three fused benzene rings derived from coal-tar. Anthracene is used in the artificial production of the red dye alizarin. It is also used in wood preservatives, insecticides, and coating materials. Anthracene is colorless but exhibits a blue (400-500 nm peak) fluorescence under ultraviolet light.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-55137070066023437512008-08-05T01:07:00.000-07:002008-08-05T01:23:35.563-07:00

Anthracite (Greek Ανθρακίτης, literally "a type of coal", from Anthrax [Άνθραξ], coal) is a hard, compact variety of mineral coal that has a high lustre. It has the highest carbon count and contains the fewest impurities of all coals, despite its lower calorific content.Anthracite coal is the highest of the metamorphic rank, in which the carbon content is between 92% and 98%. The term is applied

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-34985552569111703302008-08-05T00:56:00.000-07:002008-08-05T01:07:49.838-07:00

In chemistry, antagonism is a phenomenon where two or more agents in combination have an overall effect which is less than the sum of their individual effects.The word is most commonly used in this context in biochemistry and toxicology. Interference in the physiological action of a chemical substance by another having a similar structure. For instance, a receptor antagonist is an agent that

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-22217630037484531902008-08-05T00:49:00.001-07:002008-08-05T00:55:36.255-07:00

An antacid is any substance, generally a base or basic salt, which counteracts stomach acidity. In other words, antacids are stomach acid neutralizers.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-14104775229452704142008-07-14T06:46:00.000-07:002008-07-14T06:47:02.478-07:00

Chronic Hypoxia is a pathological condition in which the body as a whole (generalized hypoxia) or region of the body (tissue hypoxia) is deprived of adequate oxygen supply. However variations in arterial oxygen concentration can be part of normal physiology eg during strenuous physical exercise due to mismatch between supply and demand for oxygen at the cellular level. Hypoxia in which there is

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-61659453891254668912008-07-14T06:36:00.000-07:002008-07-14T06:44:00.229-07:00

In sugar chemistry, an anomer is a special type of epimer. It is a stereoisomer (diastereomer, more exactly) of a saccharide (in the cyclic form) that differs only in its configuration at the hemiacetal (or hemiketal) carbon, also called the anomeric carbon. If the structure is analogous to one with the hydroxyl group on the anomeric carbon in the axial position of glucose, then the sugar is an

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-38415359739196187932008-07-14T06:30:00.000-07:002008-07-14T06:34:38.128-07:00

An anode is an electrode through which (positive) electric current flows into a polarized electrical device. Mnemonic: ACID (Anode Current Into Device). Electrons flow in the opposite direction to the positive electric current.A widespread misconception is that anode polarity is always positive. This is often incorrectly inferred from the correct fact that in all electrochemical devices

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-14547042815601978372008-07-14T06:28:00.000-07:002008-07-14T06:29:31.145-07:00

Anions are negatively charged ions, formed when an atom gains electrons in a reaction. Anions are negatively charged because there are more electrons associated with them than there are protons in their nuclei.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-91782055735595203422008-07-14T06:07:00.000-07:002008-07-14T06:12:00.643-07:00

Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H7N. It is the simplest and one of the most important aromatic amines, being used as a precursor to more complex chemicals. Its main application is in the manufacture of polyurethane. Like most volatile amines, it possesses the somewhat unpleasant odour of rotten fish and also has a burning aromatic taste; it is a

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-8220742208483066672008-07-14T06:02:00.000-07:002008-07-14T06:06:56.367-07:00

The presence of angle strain in a molecule indicates that in a specific chemical conformation there exist bond angles that deviate from the ideal bond angles required to achieve maximum bond strength. Maximum bond strength results from effective overlap of atomic orbitals in a chemical bond.Angle strain typically affects cyclic molecules because non-cyclic molecules will thermodynamically conform

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-59805475797935616942008-07-14T05:57:00.000-07:002008-07-14T06:00:07.380-07:00

As a general term, a substance is said to be anhydrous if it contains no water. The way of achieving the anhydrous form differs from one substance to another.

Lindanoreply@blogger.comtag:blogger.com,1999:blog-1177609792126861167.post-48071713432166477032008-07-14T00:49:00.001-07:002008-07-14T00:53:19.337-07:00

In chemistry, an anhydride is a compound that can be considered as derived from another compound by subtracting the molecules of water.For example:2 NaOH - H2O → Na2OH2SO4 - H2O → SO3 Thus sodium oxide is an anhydride of sodium hydroxide, and sulfur trioxide is an anhydride of sulfuric acid.In organic chemistry, the compounds most commonly involved are carboxylic acids.2 CH3COOH - H2O → (CH3CO)2O

Lindanoreply@blogger.com