Chemistry, HYD-KRY
How do you use raw plant materials to manufacture a best-selling perfume? How do you engineer household products that are compliant with environmentally-oriented guidelines? The answers to these questions require an understanding of the laws of chemistry, the science that deals with the properties, composition, and structure of elements and compounds, as well as the transformations that such substances undergo and the energy that is released or absorbed during those processes. Chemistry is also concerned with the utilization of natural substances and the creation of artificial ones. Over time, more than 8,000,000 different chemical substances, both natural and artificial, have been characterized and produced. Chemistry's vast scope comprises organic, inorganic, physical, analytical, and industrial chemistry, along with biochemistry, environmental chemistry, medicinal chemistry, and much more. Through the dedicated efforts of people such as Robert Boyle, Dmitri Mendeleev, John Dalton, Marie Curie, and Rosalind Franklin, the field of chemistry has led to exciting innovations as well as crucial advances in our understanding of how the world functions, starting with the miniscule and unassuming atom.
Chemistry Encyclopedia Articles By Title
hydrogenation
hydrogenation, chemical reaction between molecular hydrogen and an element or compound, ordinarily in the presence......
Hydrolase
Hydrolase, any one of a class of more than 200 enzymes that catalyze the hydrolysis of several types of compounds.......
hydrolysis
hydrolysis, in chemistry and physiology, a double decomposition reaction with water as one of the reactants. Thus,......
hydroquinone
hydroquinone, colourless, crystalline organic compound formed by chemical reduction of benzoquinone. See...
hydroxide
hydroxide, any chemical compound containing one or more groups, each comprising one atom each of oxygen and hydrogen......
hydroxyl group
hydroxyl group (―OH), in chemistry, a functional group with one hydrogen and one oxygen atom. An oxygen atom normally......
hydroxylamine
hydroxylamine, (NH2OH), an oxygenated derivative of ammonia, used in the synthesis of oximes from aldehydes and......
hydroxylapatite
hydroxylapatite, phosphate mineral, calcium hydroxide phosphate [Ca5(PO4)3OH], that forms glassy, often green crystals......
Hydroxylysine
Hydroxylysine, glycogenic amino acid uniquely found in collagen, the chief structural protein of mammalian skin......
Hydroxyproline
Hydroxyproline, an amino acid formed upon hydrolysis of connective-tissue proteins such as collagen (about 14 percent......
hyoscyamine
hyoscyamine, the chief alkaloid occurring in the leaves and the tops of henbane, deadly nightshade (belladonna),......
Héroult, Paul-Louis-Toussaint
Paul-Louis-Toussaint Héroult was a French chemist who invented the electric-arc furnace—widely used in making steel—and,......
Ibogaine
Ibogaine, hallucinogenic drug and the principal iboga alkaloid, found in the stems, leaves, and especially in the......
ibuprofen
ibuprofen, nonsteroidal anti-inflammatory drug used in the treatment of minor pain, fever, and inflammation. Like......
ice
ice, solid substance produced by the freezing of water vapour or liquid water. At temperatures below 0 °C (32 °F),......
imidazole
imidazole, any of a class of organic compounds of the heterocyclic series characterized by a ring structure composed......
indium
indium (In), chemical element, rare metal of main Group 13 (IIIa, or boron group) of the periodic table. Indium......
indole
indole, a heterocyclic organic compound occurring in some flower oils, such as jasmine and orange blossom, in coal......
Induced-fit theory
Induced-fit theory, model proposing that the binding of a substrate or some other molecule to an enzyme causes......
Induction
Induction, in enzymology, a metabolic control mechanism with the effect of increasing the rate of synthesis of......
industrial polymers, chemistry of
chemistry of industrial polymers, structure and composition of chemical compounds made up of long, chainlike molecules.......
industrial polymers, major
major industrial polymers, chemical compounds used in the manufacture of synthetic industrial materials. In the......
Ingenhousz, Jan
Jan Ingenhousz was a Dutch-born British physician and scientist who is best known for his discovery of the process......
inhibin
inhibin, hormone secreted by the granulosa cells in the ovaries of women that acts primarily to inhibit the secretion......
Inhibition
Inhibition, in enzymology, a phenomenon in which a compound, called an inhibitor, in most cases similar in structure......
initiator
initiator, a source of any chemical species that reacts with a monomer (single molecule that can form chemical......
inorganic chemistry
inorganic chemistry, field of science concerned with the composition, properties, and structure of chemical elements......
inorganic compound
inorganic compound, any substance in which two or more chemical elements (usually other than carbon) are combined,......
Inosinic acid
Inosinic acid, a compound important in metabolism. It is the ribonucleotide of hypoxanthine and is the first compound......
Inositol
Inositol, any of several stereoisomeric alcohols similar in molecular structure to the simple carbohydrates. The......
Insulin
Insulin, hormone that regulates the level of sugar (glucose) in the blood and that is produced by the beta cells......
insulin-like growth factor
insulin-like growth factor (IGF), any of several peptide hormones that function primarily to stimulate growth but......
Interferon
Interferon, any of several related proteins that are produced by various types of cells in the body as a defensive......
Interleukin
Interleukin (IL), any of a group of naturally occurring proteins that mediate communication between cells. Interleukins......
intermetallic compound
intermetallic compound, any of a class of substances composed of definite proportions of two or more elemental......
Intrinsic factor
Intrinsic factor, a glycoprotein (i.e., a complex compound containing both polysaccharide and protein components)......
Inulin
Inulin, polysaccharide that is a commercial source of the sugar fructose. It occurs in many plants of the family......
inversion
inversion, in chemistry, the spatial rearrangement of atoms or groups of atoms in a dissymmetric molecule, giving......
iodine
iodine (I), chemical element, a member of the halogen elements, or Group 17 (Group VIIa) of the periodic table.......
iodoform
iodoform, a yellow, crystalline solid belonging to the family of organic halogen compounds, used as an antiseptic......
ion
ion, any atom or group of atoms that bears one or more positive or negative electrical charges. Positively charged......
ion-exchange capacity
ion-exchange capacity, measure of the ability of an insoluble material to undergo displacement of ions previously......
ion-exchange reaction
ion-exchange reaction, any of a class of chemical reactions between two substances (each consisting of positively......
ion-exchange resin
ion-exchange resin, any of a wide variety of organic compounds synthetically polymerized and containing positively......
ionic compound
ionic compound, any of a large group of chemical compounds consisting of oppositely charged ions, wherein electron......
Ipatieff, Vladimir Nikolayevich
Vladimir Nikolayevich Ipatieff was a Russian-born American chemist who was one of the first to investigate high-pressure......
iridium
iridium (Ir), chemical element, one of the platinum metals of Groups 8–10 (VIIIb), Periods 5 and 6, of the periodic......
iridosmine
iridosmine, mineral consisting of an alloy of iridium and a smaller proportion of osmium. It occurs in gold-bearing......
iron
iron (Fe), chemical element, metal of Group 8 (VIIIb) of the periodic table, the most-used and cheapest metal.......
Iron oxide
Iron oxide, chemical compound that contains the elements iron and oxygen in different proportions. Different types......
Is Spontaneous Human Combustion Real?
Late at night on Christmas Eve 1885, in the small farming town of Seneca, Illinois, a woman named Matilda Rooney......
isocyanide
isocyanide, any of a class of organic compounds having the molecular structure R―N+ ≡ C, in which R is a combining......
isodrin
isodrin, chlorine-containing organic compound used as an insecticide; see...
Isoleucine
Isoleucine, an amino acid present in most common proteins, sometimes comprising 2 to 10 percent by weight. First......
Isomerase
Isomerase, any one of a class of enzymes that catalyze reactions involving a structural rearrangement of a molecule.......
isomerization
isomerization, the chemical process by which a compound is transformed into any of its isomeric forms, i.e., forms......
isoprene
isoprene, a colourless, volatile liquid hydrocarbon obtained in processing petroleum or coal tar and used as a......
Isoprenoid
Isoprenoid, any of a class of organic compounds composed of two or more units of hydrocarbons, with each unit consisting......
isopropyl alcohol
isopropyl alcohol, one of the most common members of the alcohol family of organic compounds. Isopropyl alcohol......
isotope
isotope, one of two or more species of atoms of a chemical element with the same atomic number and position in......
isotopic tracer
isotopic tracer, any radioactive atom detectable in a material in a chemical, biological, or physical system and......
Jackson, Charles Thomas
Charles Thomas Jackson was an American physician, chemist, and pioneer geologist and mineralogist. Jackson received......
Julian, Percy
Percy Julian was an American chemist, known for his synthesis of cortisone, hormones, and other products from soybeans.......
Juvenile hormone
Juvenile hormone, a hormone in insects, secreted by glands near the brain, that controls the retention of juvenile......
Jābir ibn Ḥayyān, Abū Mūsā
Abū Mūsā Jābir ibn Ḥayyān was a Muslim alchemist known as the father of Arabic chemistry. He systematized a “quantitative”......
Kagan, Henri B.
Henri B. Kagan is a French chemist who was awarded the 2026 Nobel Prize for Chemistry for his work on nonlinear......
Kamacite
Kamacite, mineral consisting of iron alloyed with 5–7 percent nickel by weight and found in almost all meteorites......
Karikó, Katalin
Katalin Karikó is a Hungarian-born biochemist known for her pioneering research into RNA (ribonucleic acid) therapeutics,......
Karle, Jerome
Jerome Karle was an American crystallographer who, along with Herbert A. Hauptman, was awarded the Nobel Prize......
Karplus, Martin
Martin Karplus was an American Austrian chemist who was awarded the 2013 Nobel Prize for Chemistry for developing......
Karrer, Paul
Paul Karrer was a Swiss chemist who investigated the constitution of carotenoids, flavins, and vitamins A and B2,......
Kekule von Stradonitz, August
August Kekule von Stradonitz was a German chemist who established the foundation for the structural theory in organic......
Kendall, Edward Calvin
Edward Calvin Kendall was an American chemist who, with Philip S. Hench and Tadeus Reichstein, won the Nobel Prize......
Kendrew, Sir John Cowdery
Sir John Cowdery Kendrew was a British biochemist who determined the three-dimensional structure of the muscle......
Keratin
Keratin, fibrous structural protein of hair, nails, horn, hoofs, wool, feathers, and of the epithelial cells in......
ketene
ketene, any of a class of organic compounds containing the functional grouping C=C=O; the most important member......
ketoconazole
ketoconazole, antifungal drug used to treat skin and bodily infections caused by various types of fungi. Ketoconazole......
ketone
ketone, any of a class of organic compounds characterized by the presence of a carbonyl group in which the carbon......
Kevlar
Kevlar, trademarked name of poly-para-phenylene terephthalamide, a nylonlike polymer first produced by Du Pont......
Khorana, Har Gobind
Har Gobind Khorana was an Indian-born American biochemist who shared the 1968 Nobel Prize for Physiology or Medicine......
kinase
kinase, an enzyme that adds phosphate groups (PO43−) to other molecules. A large number of kinases exist—the human......
Kipping, Frederic Stanley
Frederic Stanley Kipping was a British chemist who pioneered in the chemistry of silicones, organic derivatives......
Kirwan, Richard
Richard Kirwan was an Irish chemist known for his contributions in several areas of science. Kirwan, who was born......
Kitagawa, Susumu
Susumu Kitagawa is a Japanese chemist who is known for developing metal-organic frameworks (MOFs), a class of highly......
Klaproth, Martin Heinrich
Martin Heinrich Klaproth was a German chemist who discovered uranium (1789), zirconium (1789), and cerium (1803).......
Klaus, Karl Karlovich
Karl Karlovich Klaus was a Russian chemist (of German origin) credited with the discovery of ruthenium in 1844.......
Klug, Aaron
Aaron Klug was a Lithuanian-born British chemist who was awarded the 1982 Nobel Prize for Chemistry for his investigations......
Knorr, Ludwig
Ludwig Knorr was a German chemist who discovered antipyrine. Knorr was educated at Munich, Heidelberg, Erlangen,......
Knowles, William S.
William S. Knowles was an American chemist who, with Noyori Ryōji and K. Barry Sharpless, won the Nobel Prize for......
Kobilka, Brian K.
Brian K. Kobilka is an American physician and molecular biologist whose research on the structure and function......
Kohn, Walter
Walter Kohn was an Austrian-born American physicist who, with John A. Pople, received the 1998 Nobel Prize in Chemistry.......
Kolbe, Hermann
Hermann Kolbe was a German chemist who accomplished the first generally accepted synthesis of an organic compound......
Kopp, Hermann Franz Moritz
Hermann Franz Moritz Kopp was a German chemist and historian of chemistry whose studies of the relation of physical......
Kornberg, Arthur
Arthur Kornberg was an American biochemist and physician who received (with Severo Ochoa) the 1959 Nobel Prize......
Kornberg, Roger D.
Roger D. Kornberg is an American chemist, who won the Nobel Prize for Chemistry in 2006 for his research on the......
Kossel, Albrecht
Albrecht Kossel was a German biochemist who was awarded the Nobel Prize for Physiology or Medicine in 1910 for......
Krebs, Edwin Gerhard
Edwin Gerhard Krebs was an American biochemist, winner with Edmond H. Fischer of the 1992 Nobel Prize for Physiology......
Krebs, Sir Hans Adolf
Sir Hans Adolf Krebs was a German-born British biochemist who received (with Fritz Lipmann) the 1953 Nobel Prize......
Kroto, Sir Harold W.
Sir Harold W. Kroto was an English chemist who, with Richard E. Smalley and Robert F. Curl, Jr., was awarded the......
krypton
krypton (Kr), chemical element, a rare gas of Group 18 (noble gases) of the periodic table, which forms relatively......