Matter & Energy, CHA-COU
Matter is the material substance that constitutes the observable universe and, together with energy, forms the basis of all objective phenomena. Energy, in physics, is the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms.
Matter & Energy Encyclopedia Articles By Title
Charlesās law
Charlesās law, a statement that the volume occupied by a fixed amount of gas is directly proportional to its absolute......
chelate
chelate, any of a class of coordination or complex compounds consisting of a central metal atom attached to a large......
chemical association
chemical association, the aggregation of atoms or molecules into larger units held together by forces weaker than......
chemical bonding
chemical bonding, any of the interactions that account for the association of atoms into molecules, ions, crystals,......
- Introduction
- Conservation, Mass, Law
- Ionic, Covalent, Compounds
- Visualization, Atoms, Molecules
- Discovery, Electron, Atom
- Atomic Structure, Intermolecular Forces, Covalent Bonds
- Atomic Orbitals, Shapes, Hybridization
- Periodic Arrangement, Trends
- Electron Affinity, Intermolecular Forces, Covalent Bonds
- Born-Haber Cycle, Ionic Bonds, Covalent Bonds
- Covalent, Molecules, Atoms
- Hypervalence, Electrons, Atoms
- Molecular Shapes, VSEPR Theory
- Noncentral Atoms, Molecules
- Polarization, Intermolecular Forces, Covalent Bonds
- Quantum Mechanics, Electrons, Atoms
- Electron Sharing, Covalent Bonds, Polar Bonds
- Resonance, Structures, Interactions
- Molecular Orbitals, H2, He2
- Polyatomic Species, Molecular Orbitals
- Intermolecular, Forces, Attraction
- Hydrogen Bond, Intermolecular Forces, Molecules
- Molecular, Solids, Structure
- Ionic, Covalent, Polar
- Boranes, Covalent, Hydrogen
chemical compound
chemical compound, any substance composed of identical molecules consisting of atoms of two or more chemical elements.......
- Introduction
- Trends, Elements, Properties
- Elements, Molecules, Reactions
- Binary, Covalent, Molecules
- Bonding, Structure, Properties
- Functional Groups
- Alcohols, Phenols, Structure
- Synthesis, Reactions, Properties
- Spectroscopy, Organic, Analysis
- Proton MR, Spectroscopy, Structure
- Mass Spectrometry, Molecules, Elements
- Acid, Base, Reactions
chemical element
chemical element, any substance that cannot be decomposed into simpler substances by ordinary chemical processes.......
- Introduction
- Atomic Structure, Periodic Table, Properties
- Cosmic Abundances, Elements, Periodic Table
- Solar System, Atomic Structure, Properties
- Fusion, Fission, Supernovae
- Neutron Capture, Radioactive Decay, Isotopes
- Fusion, Nucleosynthesis, Stellar
- Fusion, Supernovae, Stars
- Geochemistry, Distribution, Elements
- Mantle, Composition, Structure
- Atoms, Molecules, Compounds
- Sedimentary Rocks
- Ore Deposits
- Fossil Fuels, Hydrocarbons, Combustion
- Soil Composition, Properties, Reactions
- Salinity, Minerals, Oceans
- Atmosphere, Compounds, Elements
- Geochemical Cycle, Atomic Structure, Reactivity
- Magmatism, Sedimentation, Metamorphism
chemical energy
chemical energy, Energy stored in the bonds of chemical compounds. Chemical energy may be released during a chemical......
chemical indicator
chemical indicator, any substance that gives a visible sign, usually by a colour change, of the presence or absence......
chemical precipitation
chemical precipitation, formation of a separable solid substance from a solution, either by converting the substance......
chemical reaction
chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different......
chemical symbol
chemical symbol, short notation derived from the scientific name of a chemical elementāe.g., S for sulfur and Si......
chemiluminescence
chemiluminescence, emission of electromagnetic radiation during the course of chemical reactions. Such radiation,......
chemokine
chemokine, any of a group of small hormonelike molecules that are secreted by cells and that stimulate the movement......
Cherenkov radiation
Cherenkov radiation, light produced by charged particles when they pass through an optically transparent medium......
Chitin
Chitin, white, horny substance found in the outer skeleton of insects, crabs, and lobsters and in the internal......
chlordane
chlordane, a largely banned organochlorine insecticide. Chlordane is a thick, odourless, amber liquid with a molecular......
chlorine
chlorine (Cl), chemical element, the second lightest member of the halogen elements, or Group 17 (Group VIIa) of......
chlorobenzene
chlorobenzene, a colourless, mobile liquid with a penetrating almondlike odour; it belongs to the family of organic......
chloroform
chloroform (CHCl3), nonflammable, clear, colourless liquid that is denser than water and has a pleasant etherlike......
chlorophenol
chlorophenol, any of a group of toxic, colourless, weakly acidic organic compounds in which one or more of the......
chloropicrin
chloropicrin (Cl3CNO2), toxic organic compound used alone or in combination with methyl bromide as a soil fumigant......
chlorotrifluoroethylene
chlorotrifluoroethylene, flammable, colourless gas that belongs to the family of organic halogen compounds, used......
Cholecystokinin
Cholecystokinin (CCK), a digestive hormone released with secretin when food from the stomach reaches the first......
Cholesterol
Cholesterol, a waxy substance that is present in blood plasma and in all animal tissues. Chemically, cholesterol......
Choline
Choline, a nitrogen-containing alcohol related to the vitamins in activity. It is apparently an essential nutrient......
chromatography
chromatography, technique for separating the components, or solutes, of a mixture on the basis of the relative......
chromium
chromium (Cr), chemical element of Group 6 (VIb) of the periodic table, a hard steel-gray metal that takes a high......
chromophore
chromophore, a group of atoms and electrons forming part of an organic molecule that causes it to be coloured.......
cinnabar
cinnabar, mercury sulfide (HgS), the chief ore mineral of mercury. It is commonly encountered with pyrite, marcasite,......
circuit breaker
circuit breaker, automatic switch in an electric circuit. Its function is similar to that of a fuseāto open the......
citral
citral (C10H16O), a pale yellow liquid, with a strong lemon odour, that occurs in the essential oils of plants.......
citric acid
citric acid, a colourless crystalline organic compound belonging to the family of carboxylic acids, present in......
citronella oil
citronella oil, member of a class of naturally occurring organic substances called terpenes. Citronella oil is......
cloud chamber
cloud chamber, radiation detector, originally developed between 1896 and 1912 by the Scottish physicist C.T.R.......
cluster
cluster, Atoms and molecules are the smallest forms of matter typically encountered under normal conditions and......
CNO cycle
CNO cycle, sequence of thermonuclear reactions that provides most of the energy radiated by the hotter stars. It......
coal liquefaction
coal liquefaction, any process of turning coal into liquid products resembling crude oil. The two procedures that......
cobalt
cobalt (Co), chemical element, ferromagnetic metal of Group 9 (VIIIb) of the periodic table, used especially for......
cobalt-60
cobalt-60, radioactive isotope of cobalt used in industry and medicine. Cobalt-60 is the longest-lived radioactive......
coefficient of friction
coefficient of friction, ratio of the frictional force resisting the motion of two surfaces in contact to the normal......
Coenzyme
Coenzyme, Any of a number of freely diffusing organic compounds that function as cofactors with enzymes in promoting......
Cofactor
Cofactor, a nonprotein component that is essential for the biological activity of an enzyme. Enzymes serve as catalysts......
Cohenite
Cohenite, an iron nickel carbide mineral with some cobalt [(Fe,Ni,Co)3C] that occurs as an accessory constituent......
coherence
coherence, a fixed relationship between the phase of waves in a beam of radiation of a single frequency. Two beams......
cohesion
cohesion, in physics, the intermolecular attractive force acting between two adjacent portions of a substance,......
coincidence counting
coincidence counting, in physics, the almost simultaneous detection of two nuclear or subatomic particles (e.g.,......
Collagen
Collagen, any of a group of proteins that are components of whitish fibers of great tensile strength, such as those......
colligative property
colligative property, in chemistry, any property of a substance that depends on, or varies according to, the number......
collimator
collimator, device for changing the diverging light or other radiation from a point source into a parallel beam.......
collision
collision, in physics, the sudden, forceful coming together in direct contact of two bodies, such as, for example,......
colloid
colloid, any substance consisting of particles substantially larger than atoms or ordinary molecules but too small......
colony-stimulating factor
colony-stimulating factor (CSF), any of a group of naturally occurring proteins that play a vital role in the formation......
Color wheel
Color wheel, diagram used in the visual arts to represent the colors of the visible spectrum and their relationships......
colorimetry
colorimetry, measurement of the wavelength and the intensity of electromagnetic radiation in the visible region......
colour
colour, the aspect of any object that may be described in terms of hue, lightness, and saturation. In physics,......
colour centre
colour centre, defect in the regular spacing of atoms within a solid that absorbs visible light of a particular......
column chromatography
column chromatography, in analytical chemistry, method for separating mixtures of substances in which a liquid......
combination tone
combination tone, in musical acoustics, faint tone produced in the inner ear by two simultaneously sounded musical......
combustion
combustion, a chemical reaction between substances, usually including oxygen and usually accompanied by the generation......
Competitive inhibition
Competitive inhibition, in biochemistry, phenomenon in which a substrate molecule is prevented from binding to......
complementarity principle
complementarity principle, in physics, tenet that a complete knowledge of phenomena on atomic dimensions requires......
Complementary color
Complementary color, one of a pair of colors that are opposite each other on the traditional color wheel. The complementary......
complex
complex, in chemistry, a substance, either an ion or an electrically neutral molecule, formed by the union of simpler......
complexity
complexity, a scientific theory which asserts that some systems display behavioral phenomena that are completely......
compression
compression, decrease in volume of any object or substance resulting from applied stress. Compression may be undergone......
Compton effect
Compton effect, increase in wavelength of X-rays and other energetic electromagnetic radiations that have been......
Condensation
Condensation, transition of a gas into a liquid or a solid, generally upon a surface that is cooler than the adjacent......
conductivity
conductivity, term applied to a variety of physical phenomena. In heat, conductivity is the quantity of heat passing......
configuration
configuration, in chemistry, the spatial arrangement of atoms in a molecule. The configuration is usually depicted......
conformation
conformation, any one of the infinite number of possible spatial arrangements of atoms in a molecule that result......
conjugated system
conjugated system, in a covalent chemical compound, a group or chain of atoms bearing valence electrons that are......
conservation of linear momentum
conservation of linear momentum, general law of physics according to which the quantity called momentum that characterizes......
conservative force
conservative force, in physics, any force, such as the gravitational force between Earth and another mass, whose......
constringence
constringence, in optics, a measure of the dispersive power of a transparent substance for the visible spectrum.......
continuity principle
continuity principle, Principle of fluid mechanics. Stated simply, what flows into a defined volume in a defined......
convection
convection, process by which heat is transferred by movement of a heated fluid such as air or water. It is one......
Convergence and divergencedivergence
Convergence and divergencedivergence, in meteorology, the accumulation or drawing apart of air, as well as the......
Cooperativity
Cooperativity, in enzymology, a phenomenon in which the shape of one subunit of an enzyme consisting of several......
Coordinated Universal Time
Coordinated Universal Time (UTC), international basis of civil and scientific time, which was introduced on January......
coordination compound
coordination compound, any of a class of substances with chemical structures in which a central metal atom is surrounded......
coordination number
coordination number, the number of atoms, ions, or molecules that a central atom or ion holds as its nearest neighbours......
copernicium
copernicium (Cn), artificially produced transuranium element of atomic number 112. In 1996 scientists at the Institute......
copolyester elastomer
copolyester elastomer, a synthetic rubber consisting of hard polyester crystallites dispersed in a soft, flexible......
copolymer
copolymer, any of a diverse class of substances of high molecular weight prepared by chemical combination, usually......
copper
copper (Cu), chemical element, a reddish, extremely ductile metal of Group 11 (Ib) of the periodic table that is......
cordite
cordite, a propellant of the double-base type, so called because of its customary but not universal cordlike shape.......
Coriolis force
Coriolis force, in classical mechanics, an inertial force described by the 19th-century French engineer-mathematician......
cornstarch
cornstarch, substance produced through wet milling of corn (Zea mays). Wet milling separates the components of......
corrosion
corrosion, wearing away of a material, often a refined metal such as iron or copper, because of chemical reactions,......
Corticoid
Corticoid, any of a group of more than 40 organic compounds belonging to the steroid family and present in the......
corticotropin-releasing hormone
corticotropin-releasing hormone (CRH), a peptide hormone that stimulates both the synthesis and the secretion of......
Cortisol
Cortisol, steroid hormone produced and secreted by the adrenal glands. Cortisol serves a critical role in various......
Cortisone
Cortisone, a steroid hormone produced by the adrenal cortex. Introduced in 1948 for its anti-inflammatory effect......
corundum
corundum, naturally occurring aluminum oxide mineral (Al2O3) that is, after diamond, the hardest known natural......
Cosmic microwave background
Cosmic microwave background (CMB), electromagnetic radiation filling the universe that is a residual effect of......
Cosmic X-ray background
Cosmic X-ray background, X-ray radiation pervading the universe. In 1962 the first X-ray detectors were flown above......
Coulomb force
Coulomb force, attraction or repulsion of particles or objects because of their electric charge. One of the basic......
Coulombās law
Coulombās law, mathematical description of the electric force between charged objects. Formulated by the 18th-century......
coulometry
coulometry, in analytical chemistry, method for determining the quantity of a substance, based on the strict proportionality......