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Chemistry Topics

6.022e23mol-1
Avogadro′s number
8.314 JK-1mol-1
Molar gas constant.
Abegg′s Rule
This states that the difference between the maximum positive and negative valence of an element is frequently eight.
Abel Flashpoint Apparatus
A petroleum-testing apparatus for determining the flash point.
Abram′s Law
A rule that the ratio of water to cement for chemical action to impart strength to concrete is 0.85:1.
Absolute Vacuum
A volume which contains no matter.
Absorbed Dose
The amount of a chemical that enters the body of an exposed organism.
Absorption Band
A dark band in the absorption spectrum of a substance, corresponding to a range of wavelengths for which the substance absorbs more strongly than at adjacent wavelengths.
Absorption Spectroscopy
A technique for determining the concentration and structure of a substance by measuring the amount of electromagnetic radiation the sample absorbs at various wavelengths.
Absorption Spectrum
The collection of wavelengths missing from a continuous distribution of wavelengths.
Abundance Ratio
The ratio of the number of atoms of an isotope to the number of atoms of another isotope of the same element in a sample.
Ac
Actinium is a radioactive element.
Accelerator
A machine used to accelerate particles to high speeds.
Acceptor
An atom which is likely to take on one or more electrons when placed in a crystal.
Acenaphthene
Found in petroleum residues.
Acenaphthylene
A polycyclic aromatic hydrocarbon.
Acetaldehyde
Formed by the oxidation of ethanol this is a colourless fruity smelling liquid that with further oxidation forms acetic acid.
Acetamide
Colourless crystalline used industrially as a solvent.
Acetanilide
Also known as Antifebrin this is a white crystalline solid.
Acetic acid
The acid contained in vinegar.
Acetic Anhydride
The anhydride of acetic acid, used in the manufacture of plastics.
Acetone
Also known as Dimethyl Ketone, often used as a solvent.
Acetonitrile
Also known as Methyl Cyanide, a colourless poisonous liquid, used as a solvent and in organic synthesis.
Acetophenone
Colourless sweet smelling liquid, also known as Acetylbenzene and Phenyl Methyl Ketone.
Acetyl Chloride
Also known as Ethanoyl Chloride it is a colourless pungent liquid.
Acetylbenzene
Alternative name for Acetophenone.
Acetylene
Also known as Ethyne it is made by the action of water on calcium carbide.
Acetyl-Salicyclic Acid

CH3COOC6H4COOH

Commonly known as Aspirin, a white solid. Used in medicine as an antipyretic and analgesic.

Acheson Process
The Acheson process is an industrial process for the manufacture of graphite by heating coke mixed with clay.
Acid
Compound that gives off H+ ions in solution.
Acid Air
Alternative name for Hydrogen Chloride.
Acid Halide
Compounds containing a carbonyl group bound to a halogen atom.
Acid Rain
Rain that is weakly acidic due to pollution.
Acid-Base Indicator
A weak acid that has acid and base forms with sharply different colours.
Acidic
Describes a solution with a high concentration of H+ ions.
Acidic Solution
A solution in which the hydrogen ion activity is higher than that of the hydroxide ion, when the solvent is water.
Acidulant
A substance added to food or beverages to lower pH and to impart a tart, acid taste.
Acoustic Agglomeration
High intensity sound waves are used in a fluid to group suspended particles into larger aggregates.
Acrylic
Synthetic resin made from acrylic acid or a derivative thereof; acrylics possess the property of transparency and offer flame resistance.
Actinic
Pertaining to electromagnetic radiation capable of initiating photochemical reactions.
Actinide
Elements 89-102 are called actinides.
Actinium
A radioactive element.
Activated Charcoal
A porous form of carbon that acts as a powerful adsorbent.
Activated Complex
State of highest energy during a reaction.
Activation Energy
For the forward reaction is the energy required to go from reactants to the transition state.
Active Metal
A metal that is easily oxidized in air.
Active Site
A pocket or crevice on an enzyme molecule that fits reactant molecules like a hand in a glove.
Addition Reaction
A chemical reaction in which two atoms or groups of atoms are added across a double bond.
Adhesive Tape
A tape with a sticky substance on one side.
Adipic Acid
White crystalline solid used in the manufacture of nylon.
Adsorb
To collect molecules of a substance on a surface.
Adsorbent
A substance that collects molecules of another substance on its surface.
Adsorbtion Chromatography
A technique for separating or analyzing mixtures that contain at least one component that is preferentially adsorbed by the stationary phase as it moves over it.
Aeolotropy
Aeolotropy is the antithesis of isotropy.
Aeration
Preparation of a saturated solution of air gases by either spraying the solution in air or by bubbling air through it.
Aero Metal
A metal used in casting made from aluminium, zinc and copper.
Aerobic
Requiring or occurring in the presence of oxygen.
Aerosol
A colloid in which solid particles or liquid droplets are suspended in a gas.
Affinity
Chemical attraction.
Ag
Silver is a pure white metallic element. The best electrical conductor and used in photographic emulsions.
Ag2S
Chemical formula for Silver Sulphide.
Agar
A gel made from seaweed used to make salt bridges.
AgI
Chemical formula for Silver Iodide.
AgNO3
Silver Nitrate.
Air
The main constituents of air are Nitrogen, Oxygen, Argon, Carbon Dioxide, Neon, Helium along with a number of other trace gases.
Air Set Cement
A cement that sets through loss of water.
Al
Aluminium is the basis for a number of alloys.
Al2Br6
Chemical formula for Aluminium Bromide.
Al2I6
Chemical formula for Aluminium Iodide.
Al2O3
Chemical formula for aluminium oxide.
Al2O32H2O
Chemical formula for Bauxite.
Al2S3
Chemical formula for Aluminium Sulphide.
Alabamine
The name originally proposed for Astatine.
AlCl3
Chemical formula for Aluminium Chloride.
Alcohol
An alcohol is an organic compound with a carbon bound to a hydroxyl group.
Aldehyde
Prepared by the oxidation of primary alcohols so that the OH group loses its hydrogen to give an oxygen joined by a double bond to a carbon atom.
AlF3
Chemical formula for Aluminium Fluoride.
AlH3
Chemical formula for Aluminium Hydride.
Aliphatic
An organic compound that does not contain ring structures.
Aliquot
A sample of precisely determined amount taken from a material.
Alkali
A substance that dissolves in water to give a solution of aqueous hydroxide ions that is capable of turning red litmus blue.
Alkali Metal
A metal in group IA of the periodic table that form strongly alkaline hydroxides.
Alkaline
Having a pH greater than 7.
Alkaline Air
An old name for ammonia gas.
Alkaline Earth
An oxide of an alkaline earth metal, which produces an alkaline solution in reaction with water.
Alkaline Earth Metal
A metal in group IIA of the periodic table.
Alkalinity
A measure of a material's ability to neutralize acids.
Alkaloid
A class of bitter-tasting, basic organic compounds with nitrogen-containing rings.
Alkane
A series of organic compounds with general formula CnH2n+2.
Alkene
A compound that consists of only carbon and hydrogen, that contains at least one carbon-carbon double bond.
Alkoxide
An ionic compound formed by removal of hydrogen ions from the hydroxyl group in an alcohol using reactive metals.
Alkyl
A molecular fragment derived from an alkane by dropping a hydrogen atom from the formula -CnH2n+1.
Alkyl Halide
An alkyl group attached to a halogen atom.
Alkyne
A compound that consists of only carbon and hydrogen, that contains at least one carbon-carbon triple bond.
Allo-
A prefix that designates the more stable of a pair of geometric isomers.
Allobar
A form of an element that has isotopic abundances that are different from the naturally occuring form.
Allomer
Substances with different chemical composition but the same crystalline form.
Allosteric Effect
A change in the behaviour of one part of a molecule caused by a change in another part of the molecule.
Allotriomorphic Crystal
A crystal having a normal lattice structure, but with an imperfect outward shape due to the influence of its surroundings.
Allotropy
The reversible phenomenon by which certain metals may exist in more than one crystal structure.
Alloy
A metal produced by mixing other metals.
Allyl Alcohol
Used in the manufacture of resins and many pharmaceuticals this is a colourless pungent liquid.
Almond Artificial Essential Oil
Alternative name for Benzaldehyde.
AlN
Chemical formula for Aluminium Nitride.
Alternating Copolymer
A polymer, composed of two different repeating mers, in which the different mer units systematically alternate positions along the molecular chain.
Alumel
Trade name for an alloy of nickel with up to 5% aluminium, manganese and silicon, used with chromel in K-type thermocouples.

Aluminium
Basis for a number of alloys.
Aluminium Bromide

Al2Br6

White or very pale yellow crystalline solid.

Aluminium Bronze
A copper-aluminum alloy with high tensile strength and resistance to corrosion.

Aluminium Chloride
A chloride used as a wood preservative or catalyst.

Aluminium Fluoride

AlF3

White crystalline solid.

Aluminium Hexabromide
Alternative name for Aluminium Bromide.
Aluminium Hexachloride
Alternative name for Aluminium Chloride.
Aluminium Hexaiodide
Alternative name for Aluminium Iodide.
Aluminium Hydride

AlH3

White crystalline solid.

Aluminium Hydroxide
White crystalline compound that occurs naturally as the mineral gibbsite.

Aluminium Iodide

Al2I6

White solid.

Aluminium Nitride

AlN

Bluish white crystalline solid.

Aluminium Oxide

Al2O3

Alminium oxide is the most widely used oxide ceramic, either in pure form or as raw material to be mixed with other oxides.

Aluminium Sulphide

Al2S3

Yellow or yellow grey powder.

Aluminium Tribromide
Alternative name for Aluminium Bromide.
Aluminium Trichloride
Alternative name for Aluminium Chloride.
Aluminium Triiodide
Alternative name for Aluminium Iodide.
Am
A radioactive element.
Amagat
The unit of density of a gas at stp equal to 44.614774 molm-3.
Amalgam
An alloy that contains mercury.
Americium
A radioactive element. Alpha particle emitter with a half life of 475 years.
Amide
The most stable of all the carbonyl functional groups.
Amine
A class of organic compounds in which one or more of the hydrogen atoms of ammonia have been replaced by other groups of atom.
Aminic Acid
Another name for Methanoic Acid.
Amino Acid
Amino acids are molecules that contain at least one amine group (-NH2) and at least one carboxylic acid group (-COOH).
Aminoacetic Acid
A naturally occurring aliphatic amino acid, also known as glycine.
Aminobenzene
Alternative name for Aniline.
Ammine
A metal ion complex containing ammonia as a ligand.
Ammonia
Obtained from nitrogen using the Haber process and used in the manufacture of fertilizers and explosives.
Ammonium Carbonate

(NH4)2CO3

Ammonium Chloride

NH4Cl

A clear white water-soluble crystalline salt with a biting, slightly sour taste.

Ammonium Fluoride

NH4F

Crystallizes as small prisms, having a sharp saline taste, and is exceedingly soluble in water.

Ammonium Hydrogenphosphate

(NH4)2HPO4

Used as a nutrient for the yeast in brewing.

Ammonium Hydroxide
A solution of ammonia in water.
Ammonium Iodide

NH4I

Used in photographic chemicals and some medications.

Ammonium Nitrate

NH4NO

The most known chemical property of ammonium nitrate is its combustability. This also makes it a very dangerous compound to work with.

Ammonium Sulphate

(NH4)2SO4

Fine granulated, off white or brown crystals. There may be a slight ammonia like odour. Sulphate of ammonia is a chemical fertilizer.

Amorphography
The branch of science concerned with the determination of amorphous solid structures and their systemmatic classification.
Amorphous
Non-crystalline, without long-range order.
Amount of Substance
The SI unit of the Amount of Substance is the mole.
Amperometry
Determining the concentration of a material in a sample by measuring electric current.
Amphi-
A prefix used to name certain members of a series of geometric isomers or stereoisomers.
Amphiprotic Solvent
Solvents that exhibit both acidic and basic properties.
AMU
Defined as one twelfth of the mass of the most abundant isotope of carbon (12C)
Anaerobic
Occurring in the absence of air or oxygen.
Analyte
The sample constituent whose concentration is sought in a chemical analysis.
Angstrom
It is an old unit used for measuring the wavelength of electromagnetic radiation including visible light and X-rays.
Anhydrous
A compound with all water removed, especially water of hydration.
Aniline
Also known as Phenylamine or aminobenzene.
Anion
Ions with a negative charge.
Anisole
Also known as Methyl Phenyl Ether, an aromatic smell and used in perfumes.
Anode
The electrode where electrons are lost (oxidized) in redox reactions.
Anodic Protection
A technique to reduce the corrosion rate of a metal by polarizing it into its passive region, where dissolution rates are low.
Anodic Reaction
Electrode reaction equivalent to a transfer of positive charge from the electronic to the ionic conductor; an anodic reaction is an oxidation process.
Anodize
To coat a metal with a protective film by electrolysis.
Anthocyanin
A family of pigments that give flowers, fruits, and leaves of some plants their red or blue colouring.
Anthracene
White crystalline with a blue fluorescence used in the manufacture of dyes.
Anthracite
Type of coal with highest carbon content (86% to 98%) and thus highest heat value .

Anthraquinone
Yellow powder derived from Anthracene and used as a dye.
Antichlor
A chemical compound that reacts with chlorine-based bleaches to stop the bleaching.
Antifebrin
Alternative name for Acetanilide.
Antimony
Elemental antimony is generally found in one of two allotropes and has both metallic and non-metallic properties.
Antimony Hydride

SbH3

Poisonous gas. Also known as Stibine.

Antipyretic
A substance that can lessen or prevent fever.
Aprotic Solvent
A solvent that does not act as an acid or as a base.
Aqua Fortis
Ancient name for Nitric Acid, a colourless, corrosive, acid liquid that attacks most metals and other substances.
Aqua Regia
A mixture of nitric and hydrochloric acids used to dissolve gold.
Aqueous Solution
A solution in which water is the dissolving medium or solvent.
Ar
An inert gas that makes up about 1% of the atmosphere.
Arene
A hydrocarbon that contains at least one aromatic ring.
Argentite
Naturally occuring Silver Sulphide. An important ore of silver.
Argentum
Latin for silver, hence the symbol Ag.
Argon
An inert gas that makes up about 1% of the atmosphere.
Aromatic Compound
A compound containing an aromatic ring.
Aromatic Ring
An exceptionally stable planar ring of atoms with resonance structures that consist of alternating double and single bonds, e. g. benzene.
Arsenic
A brittle, crystalline solid which tarnishes readily in air and burns in oxygen.
Arsenic III Oxide

As2O3

White crystalline solid, used as an opacifier in glazes.

Arsenic V Oxide

As2O5

White solid.

Arsenical Bronze
An alloy of copper and arsenic in addition to other metals.

Arsenical Copper
An alloy of copper and arsenic in addition to other metals.
Arsine
Old name for Hydrogen Arsenide.
Aryl
A molecular fragment or group attached to a molecule by an atom that is on an aromatic ring.
As
A brittle, crystalline solid which tarnishes readily in air and burns in oxygen.
As2O3
Chemical formula for Arsenic III Oxide.
As2O5
Chemical formula for Arsenic V Oxide.
Asbestos
This description covers a number of fibrous silicate minerals such as calcium magnesium silicate.
AsH3
Chemical formula for Hydrogen Arsenide.
Aspartic Acid
A nonessential amino acid that is abundant in molasses.
Aspirin
Common name for Acetyl-Salicyclic Acid.
Assay
A quantitative determination of the metal in an ore or alloy.
Astatine
The heaviest halogen and radioactive.
At
Astatine is heaviest halogen and radioactive.
Atactic
A type of polymer chain configuration wherein side groups are randomly positioned on one side of the polymer backbone or the other.
atm
An abbreviation of atmosphere.
Atom
The smallest particle of an element that can exist and still retain the ordinary chemical properties of that element.
Atom Percent
Concentration specification on the basis of the number of moles or atoms of a particular element relative to the total number of moles or atoms of all elements within an alloy.
Atomic Number
The atomic number (Z) of an element is the number of protons each atom of that element has in its nucleus.
Atomic Orbital
A wavefunction that describes the behavior of an electron in an atom.
Atomic Packing Factor
The fraction of the volume of a unit cell that is occupied by ′hard sphere′ atoms or ions.
Atomic weight
The weighted average mass of the atoms in a naturally occurring element.
Au
Gold is a soft metal with a characteristic yellow colour. It is the most malleable and ductile of any element. It is unaffected by air, water, alkalis and acids.
Aufbau Principle
An approximate procedure for writing the ground state electronic configuration of atoms.
Auricupride

Cu3Au

A natural alloy of copper and gold.

Aurum
Latin for gold, hence the symbol Au.
Austenite
Face-centered cubic iron; also iron and steel alloys that have the FCC crystal structure.
Autoclave
An airtight vessel constructed of thick-walled steel alloy for carrying out chemical reactions under pressure and high temperatures. Auto-claves are used for the industrial processing of composite materials.
Auto-Ignition Temperature
Minimum temperature at which the vapour/air mixture over a liquid spontaneously catches fire.
Autoxidation
Oxidation caused by exposure to air.
Auxochrome
A group or substructure in a molecule that influences the intensity of absorption of the molecule.
Avalanche
A cumulative ionization process.
Avogadros Number
N = 6.022045x1023 mol-1
Azeotrope
A solution that does not change composition when distilled.
Azobenzene
Red insoluble crystalline powder.
B
Boron is a non-metallic element which occurs in several allotropes.
B100 Biodiesel
100% biodiesel.
B20 Biodiesel
A blend of biodiesel fuel with petroleum-based diesel where 20% of the volume is biodiesel.
Ba
Elemental barium does not occur naturally although it has an abundance within the earth’s crust of 500 ppm.
Babbitt
A soft antifriction metal used to line bearings.

Back Titration
Determining the concentration of an analyte by reacting it with a known number of moles of excess reagent.
Baekeland, Leo Hendrik
Belgian-born American chemist who invented Velox photographic paper and Bakelite.
Bakelite
The first industrial thermoset plastic.
Bakers Salt
Old name for Ammonium Carbonate.
Balmer Series
A series of lines in the emission spectrum of hydrogen that involve transitions to the n=2 state from states with n>2.
Bamboo
A natural material with a great strength to weight ratio. It was used in the early construction of aircraft wings and fuselages.

Barite
Most commonly found mineral of Barium Sulphate.
Barium
Elemental barium does not occur naturally although it has an abundance within the earth’s crust of 500 ppm.
Barium Dioxide
A white toxic powder obtained by heating barium oxide in air.
Barium Monoxide
An oxide of barium; a whitish toxic powder.
Barium Oxide
An oxide of barium; a whitish toxic powder.
Barium Peroxide
A white toxic powder obtained by heating barium oxide in air.
Barium Protoxide
An oxide of barium; a whitish toxic powder.
Barium Sulphate

BaSO4

A white insoluble solid used as a pigment and filler in plastics. Most commonly found as the mineral Barite.

Barium White
An ancient name for Barium Sulphate.
Baryta
Any of several compounds of barium.
Base
Substance which gives off hydroxide ions (OH-) in solution. In the expression xy, x is called the base and y is the exponent.
BaSO4
Chemical formula for Barium Sulphate.
Bath Metal
A cheap bronze made with 21 parts copper and 5 parts zinc. The same as pinchbeck.

Bauxite
An ore of aluminum consisting of moderately pure hydrated alumina.
Bay Salt
Alternative name for Sodium Chloride.
bcc
Abbreviation of body centred cubic. About 15% of all the elements crystallize into this structure.
Be
Beryllium is a light and lustrous metal that is resistant to attack by air or water, even at elevated temperatures
Be3N2
Chemical formula of Beryllium Nitride.
BeBr2
Chemical formula of Beryllium Bromide.
BeCl2
Chemical formula of Beryllium Chloride.
BeF2
Chemical formula of Beryllium Fluoride.
BeI2
Chemical formula of Beryllium Iodide.
Bell Metal
Copper tin alloy with much higher tin content than conventional bronze in order to make it hard and sonorous. It is too brittle to be used for many other applications.

Benzaldehyde

C6H5CHO

A colourless to yellow liquid with an almon like odour. Also known as Benzoic Aldehyde, Almond Artificial Essential Oil, Benzenecarbonal, Benzene Carboxaldehyde and Oil of Bitter Almond.

Benzene
An aromatic hydrocarbon used in the manufacture of many organic compounds.
Benzene Carboxaldehyde
Alternative name for Benzaldehyde.
Benzenecarbonal
Alternative name for Benzaldehyde.
Benzoic Acid

C6H5.COOH

Used as a fruit preservative. At room temperature it is a colourless solid forming glistening needles and plates, sublimes easily and is volatile in steam.

Benzoic Aldehyde
Alternative name for Benzaldehyde.
BeO
Chemical formula of Beryllium Oxide.
Berkelium
Element with an atomic number of 97.
Beryllia
Alternative name for Beryllium Oxide.
Beryllia Ceramic
Alternative name for Beryllium Oxide.
Beryllium
Beryllium is a light and lustrous metal that is resistant to attack by air or water, even at elevated temperatures
Beryllium Bromide

BeBr2

Hygroscopic and dissolves readily in water.

Beryllium Chloride

BeCl2

White crystalline substance that reacts vigorously and exothermically with water with the evolution of acidic, steamy hydrogen chloride gas. It attacks many metals in presence of water.

Beryllium Copper
Heat treatable copper-beryllium alloy of high strength and hardness. Used for making springs and non-sparking tools.
Beryllium Fluoride

BeF2

A crystalline solid, the principal precursor for the manufacture of beryllium metal.

Beryllium Hydroxide

Be(OH)2

A white solid. One of only a few amphoteric metal hydroxides.

Beryllium Iodide

BeI2

Colourless needle-like crystals that are very hygroscopic and reacts violently with water, forming hydroiodic acid.

Beryllium Nitride

Be3N2

A common component of refractory ceramics.

Beryllium Oxide

BeO

White crystalline oxide that when sintered is very stable and has ceramic characteristics.

Beryllium Telluride

BeTe

A crystalline solid that is a semiconductor with a large energy gap of around 3 eV.

BeTe
Chemical formula of Beryllium Telluride.
Bi
Bismuth is a brittle metal which is silvery in colour with a pink tinge.
Bifunctional Monomer
A monomer unit that has two active bonding positions.
Billon
An alloy of copper and silver with more than 50% copper.

Bimolecular Step
Two species are reacting and form the transition state.
Binary Compound
A compound that contains two different elements.
Biochemistry
The chemistry of living things, including the structure and function of biological molecules and the mechanism and products of their reactions.
Biodiesel
Diesel fuel derived from renewable lipid feedstocks, such as vegetable oils and animal fats.
Biodiesel B100
100% (neat) biodiesel. The mono alkyl esters of long chain fatty acids derived from renewable lipid feedstocks, such as vegetable oils and animal fats, diesel engines

Biodiesel B20
A blend of biodiesel fuel with petroleum-based diesel where 20% of the volume is biodiesel.
Biosensor
Either a sensor to detect a biological substance or a sensor which incorporates the use of biological molecules such as antibodies or enzymes.
Biotin
Commonly known as vitamin H.
Bismuth
Bismuth is a brittle metal which is silvery in colour with a pink tinge.
Bismuth Chloride

BiCl3

A water soluble crystalline source of bismuth.

Bismuth Germanate

Bi4Ge3O12

Used in detectors in particle physics and nuclear medicine.

Bismuth Subcarbonate

Bi2O2(CO3)

Chemical compound of bismuth containing both oxide and carbonate.

Bismuth Subgallate

C7H5BiO6

Used in medicine as an internal deodorant.

Bittern
Waste solution of magnesium salts and bromides from the preparation of salt from sea-water by evaporation.
Bitumen
A name used to describe many different mixtures of hydrocarbons.
Bk
Berkelium is an element with an atomic number of 97.
Black, Joseph
Scottish chemist who laid the foundations for thermodynamics.
Black Lead
Natural crystalline form of carbon, used to make vessels that resist high temperatures and in making pencils.
Blackett, Patrick Maynard Stuart
English chemist who developed the cloud chamber.
Blast Furnace
A vertical shaft type furnace used for reducing iron ore to pig iron when cast or hot metal for further melting. This product is used in an open hearth or basic oxygen furnaces for production of steel.
Bleach
A dilute solution of sodium hypochlorite or calcium hypochlorite which kills bacteria and destroys coloured organic materials by oxidizing them.
Block Copolymer
A linear copolymer in which identical mer units are clustered in blocks along the molecular chain.
Blue Vitriol
An old fashioned name for hydrated copper sulphate.
Body Centred Cubic
About 15% of elements crystallize with a body centred cubic structure.
Boiling Point
The temperature at which the vapour pressure of a liquid is equal to the external pressure on the liquid.
Boiling Point Elevation
The boiling point of a solution is higher than the boiling point of the pure solvent.
Bond Energy
The energy required to break a given chemical bond.
Bond Enthalpy
Enthalpy change per mole when a bond is broken in the gas phase for a particular substance.
Bond Length
The average distance between the nuclei of two bonded atoms in a stable molecule.
Bond Order
In Lewis structures, the number of electron pairs shared by two atoms.
Bond Strength
Some measure of how difficult it is to break a chemical bond, for example, a bond energy or a bond enthalpy.
Bonding Energy
The energy required to separate two atoms that are chemically bonded to each other.
Bone
Primarily based on phosphate and carbonate.
Bone Black
An impure animal charcoal prepared from bones and blood.
Boron
Boron is a non-metallic element which occurs in several allotropes.
Boyle, Robert
Known for that scientific law named after him.
bp
Abbreviation of boiling point, the temperature at which the vapour pressure of a liquid is equal to the external pressure on the liquid.
Bq
An abbreviation of Becquerel. One Becquerel is that quantity of a radioactive material that will have 1 transformations in one second.
Br
Bromine is an element in the halogen group.
Bragg′s Law
A relationship that stipulates the condition for diffraction by a set of crystallographic planes.
Branched Polymer
A polymer having a molecular structure of secondary chains that extend from the primary chains.
Brimstone
Ancient name for Sulphur.
Brominated Flame Retardants
A group of chemicals used in plastics and textiles to give flame retardant properties.
Bromine
An element in the halogen group.
Bromoethane

C2H5Br

A colourless volatile liquid that has an ether-like odour.

Bromomethane

CH3Br

A colorless, nonflammable gas with no distinctive smell.

Brösted Acid
A material that gives up hydrogen ions in a chemical reaction.
Brösted Base
A material that accepts hydrogen ions in a chemical reaction.
Buckminsterfullerene

C60

A form of carbon consisting of 60 carbon atoms bound together to make a roughly spherical "buckyball".

Buckyball
A form of carbon consisting of 60 carbon atoms bound together to make a roughly spherical buckyball.
Buffer Solutions
Solutions that resist changes in their pH, even when small amounts of acid or base are added.
Bunsen Burner
A gas burner with adjustable air intake, commonly used in laboratories.
Bunsen, Robert Wilhelm
Introduced the bunsen burner.
Buret
A cylindrical glass tube closed by a stopcock on one end and open on the other, with volume gradations marked on the barrel of the tube, used to precisely dispense a measured amount of a liquid.
Burette
A cylindrical glass tube closed by a stopcock on one end and open on the other, with volume gradations marked on the barrel of the tube, used to precisely dispense a measured amount of a liquid.
Burgess Vector
A vector that denotes the magnitude and direction of lattice distortion associated with a dislocation.
Butane

C4H10

An alkane hydrocarbon. Commonly used in compressed form for portable heaters and cookers.

Butanol
An alcohol containing four carbon atoms.

Butter of Zinc
An old name for Zinc Chloride.
Butyl Alcohol
Alternative name for Butanol.
C
Carbon occurs naturally in two allotropic forms, namely graphite and diamond.
C12H10N2
Chemical formula for Azobenzene.
C14H10
Chemical formula for Anthracene.
C14H8O
Chemical formula for Anthraquinone.
C16H32
Chemical formula for Cetene.
C2H2
Chemical formula for Acetylene.
C2H3N
Chemical formula for Acetonitrile.
C2H3OCl
Chemical formula for Acetyl Chloride.
C2H4O
Chemical formula for Acetaldehyde.
C2H5Br
Chemical formula for Bromoethane.
C2H5Cl
Chemical formula for Chloroethane.
C2H5OH
Chemical formula for ethanol.
C2H5ON
Chemical formula for Acetamide.
C2H6
Chemical formula for Ethane.
C2HCl3
Chemical formula for Trichlorethene.
C2N2
Chemical formula for Cyanogen.
C3H6
Chemical formula for Propene.
C3H6O
Chemical formula for acetone.
C3H6O2
Chemical formula for Methyl Acetate.
C3H7OH
Chemical formula for Propanol.
C3H8
Chemical formula for Propane.
C3H8O3
Chemical formula for Glycerol.
C4H10
Chemical formula for butane.
C4H12N2
Chemical formula for Putrescine.
C4H6O3
Chemical formula for Acetic Anhydride.
C4H6O5
Another name for Hydroxybutanedioic Acid.
C4H9OH
Chemical formula for Butanol.
C5H11OH
Chemical formula for Pentanol.
C5H12
Chemical formula for pentane.
C60
Buckminsterfullerene formed from 60 carbon atoms.
C6H10O4
Chemical formula for Adipic Acid.
C6H5CHO
Chemical formula for Benzaldehyde.
C6H5 COOH
Chemical formula for Benzoic Acid.
C6H5NO2
Chemical formula for nitrobenzene.
C6H5OH
Chemical formula for Phenol.
C6H6
Chemical formula for benzene, an aromatic hydrocarbon used in the manufacture of many organic compounds.
C6H6O
The chemical formula for phenol, a strong disinfectant.
C6H7N
Chemical formula for Aniline.
C7H16
Chemical formula for heptane.
C7H8
Chemical formula for toluene.
C7H8O
Chemical formula for Anisole.
C8H10N4O2
A substance found in tea, coffee, and cola that acts as a stimulant.
C8H18
Flammable liquid compounds found in petroleum and natural gas.