Ch

ch
Metric horsepower.
ch
Abbreviation of chain, an old unit of length.
CH2Cl2
Chemical formula for Dichloromethane.
CH2O2
Chemical formula for for Methanoic Acid.
CH3Br
Chemical formula for Bromomethane.
CH3CH2NH2
Chemical formula for Ethylamine.
CH3Cl
Chemical formula for Chloromethane.
CH3COOC6H4COOH
Chemical formula for Acetyl-Salicyclic Acid.
CH3COOCH2CH3
Chemical formula for Ethyl Acetate.
CH3COONH4
Chemical formula for Ammonium Acetate.
CH3OCH3
Chemical formula for Dimethyl Ether.
CH3OH
A colourless liquid also known as methyl alcohol.
CH4
The chemical formula for methane, the first alkane.
CH4O
Chemical formula for Methyl Alcohol.
Chadwick, James
English physicist who discovered the neutron.
Chain
The chain is a unit of length.
Chain Drive
Power transmission by means of an endless chain running around chain wheels or sprocket wheels.
Chain Folded Model
A model that describes the structure of platelet crystallites for crystalline polymers.
Chain Reaction
A process in which the fissioning of one nucleus initiates the fissioning of others.
Chainring Nut Spanner
A special bicycle tool used to loosen the slotted nuts that fasten a chainring to a crankarm.
Chalk
Common form of Calcium Carbonate.
Chalk Line
A string line that is covered with powdered chalk that is stretched tight on a surface and flicked leaving a straight line of chalk on the surface.
Challenge Handshake Authorisation Protocol
A protocol used for identifying and authenticating a user and his or her password.
Chamfer
Beveled corner.
Chandrasekhar Limit
A limit which mandates that no white dwarf can be more massive than about 1.4 solar masses.
Chandrasekhar, Subrahmanyan
Indian astrophysicist reknowned for creating theoretical models of white dwarf stars, among other achievements.
Change of State
The change in a substance between solid and liquid or between liquid and gas.
Channel
A frequency interval or frequency band assigned for communications.
Chaos
The breakdown of predictability, or a state of disorder.
Chaplet
A small metal insert or spacer used in moulds to provide core support during the casting process.
Chapman Strut
MacPherson strut used in a rear suspension.
Character
A letter, digit, or other symbol that is used as part of the organization, control, or representation of information.
Characteristic Equation
The mathematical equation whose solution defines the dynamic characteristics of the structure in terms of its natural frequencies, damping, and mode shapes.
Characteristic Impedance
The ratio of voltage and current at every point along a transmission line on which there are no standing waves.
Characteristic Polynomial of a Matrix
The characteristic polynomial of a n by n matrix A is the polynomial in t given by the formula det(A - tI).
Characteristic X-ray
An X-ray having a unique energy that is emitted by an atom during its de-energization after ionization of one of its electrons.
Characters per Second
A measure of how quickly information, particularly text, is being transferred over a modem link or network.
Charcoal
Used to describe different forms of carbon. Formed by heating vegetable or animal matter in the absence of air.
Charge
The excess or deficiency of electrons resulting in the body having negative or positive charge.
Charge Acceptance
The ability of a battery to convert active material during charge into a form which can be subsequently discharged.
Charge Carrier
The particle carrying the electrical charge during the flow of electrical current.
Charge Conjugation
The technical term for mathematical operations which interchange particles and antiparticles.
Charge Conservation
The observation that electric charge is conserved in any process of transformation of one group of particles into another.
Charge Cooler
A device which cools a gas between the compressive steps of a multiple stage compressor.
Charge Coupled Device
A self-scanning semiconductor imaging device which uses metal-oxide-semiconductor, surface storage and information transfer technologies.
Charge Cycle
The period of time that a capacitor in an electrical circuit is storing a charge.
Charge Density
Charge referred to the unit area of the electrode.
Charge Efficiency
The ratio of the weight of the charge actually taken in to the weight of the air at standard conditions corresponding to the piston displacement.
Charge Rate
The current applied to a rechargeable battery to restore its capacity.
Charge Transfer Reaction
A chemical reaction where an electrical charge is transferred from one reactant to another.
Charge Transfer Resistance
A characteristic quantity for an electrode reaction indicative of its inherent speed. A large charge-transfer resistance indicates a slow reaction.
Charge Transport
The phenomenon of movement of electrical charge from one part of the system to another, occurring through electromigration.
Charged
Possessing a net negative or positive charge.
Charged Particle Beam
A projected stream of charged particles.
Charged Particles
Particles with positive or negative charge, for example electrons, protons or ions.
Charging
The process of supplying electrical energy to a discharged battery for conversion to stored chemical energy.
Charging Voltage
The voltage used to overcome a battery′s internal resistance and to recharge the battery.
Charles Gas Law
For a fixed mass of gas at constant pressure the volume is directly proportional to the temperature.
Charles, Jacques Alexander CÚsar
The French scientist after which is named the Charles′s Law which made the connection that a rise in temperature expanded the volume of gas.
Charm
The flavor of the fourth quark.
Charmed
Having a nonzero value of charm.
Charmed Quark
The quark having electric charge 2/3 times the elementary charge and charm C = +1. It is more massive than the up, down, and strange quarks.
Charmonium
Any meson composed of a charmed quark and a charmed antiquark.
Charon
Pluto′s double.
Charpy Test
An impact test in which a V-notched, keyhole-notched, or U-notched specimen, supported at both ends horizontally, is struck behind the notch by a striker mounted at the lower end of a pendulum.
Chasing Threads
The process of cutting threads in a lathe or screw machine.
Chassis
The mechanical parts of a vehicle attached to a structural frame, including axles, brakes, driveshafts, and suspension components.
Chatter
The vibrations caused between the work and the cutting tool which leave distinctive tool marks on the finished surface that are objectionable.
Chatter Marks
Marks at regular intervals on a workpiece due to machine tool vibration.
CHCl3
Chemical formula for chloroform.
Check Valve
A valve that permits the passage of a liquid or gas in one direction only. It stops, or checks, reverse flow.
Checklists
Can be used as a basic method for itemizing potential hazards or undesirable outcomes that need to be considered.
Checksum
A number formed by an algorithm, possibly addition, applied to a data record.
Chelate
A stable complex of a metal with one or more polydentate ligands.
Chelating Agent
A ligand that binds to a metal using more than one atom; a polydentate ligand.
Chemical
1. of or pertaining to chemistry. 2. a substance.
Chemical Analysis
Determination of the composition of a sample.
Chemical Bond
A chemical bond is a strong attraction between two or more atoms.
Chemical Change
A chemical change is a dissociation, recombination, or rearrangement of atoms.
Chemical Differentiation
The separation of different elements, often heavier elements from lighter elements, as a consequence of different chemical reactions.
Chemical Energy
Energy stored in the bonds of atoms and molecules eg coal, petrol, biomass.
Chemical Enrichment
The process in which a star manufactures chemical elements, such as carbon and oxygen, in the nuclear reactions in its interior and then ejects these elements into space.
Chemical Equation
A compact notation for describing a chemical change.
Chemical Fastener
A glue designed to replace nails.
Chemical Formula
A representation of a chemical substance that uses chemical symbols to denote the constituent atoms, and subscripts to indicate the relative numbers of atoms of each type.
Chemical Property
Measurement of a chemical property involves a chemical change.
Chemical Reaction
A process that leads to the transformation of one set of chemical substances to another.
Chemical Rocket Engine
Contain or carry along it′s own fuel and oxidizer, usually in either liquid or solid form.
Chemical Set Cement
A cement that sets through reaction or precipitation.
Chemical Stability
The tendency of a substance or mixture to resist chemical change.
Chemical Symbols
Each element has it′s own symbol and these together build up the chemical symbols.
Chemical Vapour Deposition
A method of depositing thin semiconductor films.
Chemiluminescence
A chemical reaction that releases energy as electromagnetic radiation.
Chemistry
Lists all the Chemistry topics
Chemistry Books
Lists all Chemistry Books in the Encyclopaedia
Chemistry Conversions
Lists all Chemistry Conversions in the Encyclopaedia
Chemistry Weblinks
Lists all Chemistry Weblinks in the Encyclopaedia
Chemotroph
An organism that obtains energy by metabolizing organic compounds derived from other organisms.
Chemotropism
Movement of a plant in response to chemicals.
Cherenkov Radiation
Radiation emitted by a massive particle which is moving faster than light in the medium through which it is travelling.
Cherry
A reddish hardwood that can be stained to make a good imitation of mahogany.
Chestnut
Very durable and much like oak. Comparitavely easy to work and does not shrink much when drying.
Cheval Vapeur
Metric horsepower.
Chevron Packing
A type of packing used in packing boxes consisting of a nest of "V" cross-section rings.
CHG
Abbreviation of Compressed Hydrogen Gas.
chi
A letter of the Greek alphabet.
Child, Charles
American biologist who proposed the axial gradient theory to explain the differences in rates of metabolism along the axes of living organisms.
Chile Nitre
Another name for Sodium Nitrate.
Chiller
A device that removes heat from a liquid via a vapour-compression or absorption refrigeration cycle.
Chinese Silver
An alloy used for jewellery, 58% copper, 17.5% zinc, 11.5% nickel, 11% cobalt, and 2% silver.

Chinese White
The old name for Zinc Oxide.
Chip
A piece of semiconductor substrate on which active and/or passive circuit elements have been fabricated. Small piece of material removed from a workpiece by a cutting tool or grinding wheel.
Chipping
The process of cutting metal with a cold chisel and hammer.
Chipping Hammer
A hammer used to remove the slag from weld seams.
Chiral Centre
An atom in a molecule that causes chirality, usually an atom that is bound to four different groups.
Chirality
Handedness, the quality of having non-superimposable mirror images.
Chirp
A chirp is a sound that has a rapid increase in frequency.
Chisel
A metal hand tool with a sharp beveled edge. It is used to cut and shape wood, metal or stone.
Chlorane
Alternative name for Hydrogen Chloride.
Chlorination
The application of chlorine to drinking water, sewage, or industrial waste to disinfect or to oxidize undesirable compounds.
Chlorine
A greenish yellow gas and second in the halogen group.
Chlorobenzene

C6H5Cl

Colourless, flammable liquid is a common solvent and a widely used intermediate in the manufacture of other chemicals.

Chloroethane

C2H5Cl

A colorless, flammable gas or refrigerated liquid with a faintly sweet odour.

Chloroform
Volatile colourless heavy liquid used as an anaesthetic and solvent.
Chlorohydric Acid
Alternative name for Hydrochloric Acid.
Chloromethane

CH3Cl

A colourless extremely flammable gas with a slightly sweet odor. Once commonly used as a refrigerant.

Chlorophylls
A family of green pigments functioning as receptors of light energy in photosynthesis.
Chloroplasts
Chlorophyll-containing photosynthetic organelles in some eukaryotic cells.
Choke
An inductor designed to present a high impedance to alternating current.
Choke Joint
A joint between two sections of waveguide that provides a good electrical connection without power losses or reflections.
Cholesterol
A substance which can cause blocks in blood vessels.
Chord
A line segment that connects two points of a curve or circle.
Chord Line
A line joining the leading edge to the trailing edge.
Chordal Thermocouple
A thermocouple installed in furnace tubes, designed to measure the effectiveness of water treatment within the boiler.
Choroisotherm
A line representing equal temperature in time.
CHP
Abbreviation of Combined Heat and Power.
Chromatic Aberration
A defect in lenses that causes different colors (wavelengths) of light to have different focal lengths.
Chromatic Scale
A scale consisting of 12 semitones.
Chromatin
Dense complex consisting of double helix DNA and histones.
Chromatography
A method for separating mixtures based on differences in the speed at which they migrate over or through a stationary phase.
Chrome Green
Alternative name for Chromium Oxide.
Chrome Plating
A technique of electroplating a thin layer of chromium onto a metal or plastic object.
Chrome Yellow
An old name for Lead II Chromate IV.
Chromel
An alloy of nickel with about 10% chromium, used with Alumel in K-type thermocouples.

Chromic Oxide
Alternative name for Chromium Oxide.
Chrominance
The colour portion of the video signal that includes hue and saturation information but not brightness.
Chromium
A bright, blue/white metal with excellent corrosion resistance.
Chromium Dioxide

CrO2

A black crystalline solid.

Chromium IV Oxide
Alternative name for Chromium Dioxide.
Chromium Oxide

Cr2O3

The only stable oxide of chromium. It is a bright to dark green crystalline powder insoluble in alkalis and acids.

Chromium VI Oxide

CrO3

Highly poisonous.

Chromophore
A group or substructure on a molecule that is responsible for the absorption of light.
Chromosome
An organized structure of DNA and protein that is found in cells.
Chromosphere
The layer of the solar atmosphere above the photosphere and beneath the transition region and the corona.
Chronoamperometry
An electrochemical measuring technique used for electrochemical analysis or for the determination of the kinetics and mechanism of electrode reactions.
Chronocoulometry
An electrochemical measuring technique used for electrochemical analysis or for the determination of the kinetics and mechanism of electrode reactions.
Chronology Protection Conjecture
The concept that the formation of any closed timelike curve will automatically be destroyed by quantum fluctuations as soon as it is formed.
Chronopotentiometry
An electrochemical measuring technique used for electrochemical analysis or for the determination of the kinetics and mechanism of electrode reactions.
Chu
Abbreviation of centigrade heat unit.
Chuck
A device on a machine tool to hold the workpiece or a cutting tool.
Church, Alonzo
Mathematician and logician, and one of the founders of computer science.