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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.
Abietic Acid

C20H30O2

A resin acid that is the primary irritant in pine wood and pine resin. It is a glassy or partly crystalline yellowish solid. It belongs to the diterpene group of organic compounds. It is used in lacquers, varnishes, and soaps, and for the analysis of resins and the preparation of metal resinates.

Abietinic Acid
Another name for Abietic Acid.
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.
Acenaphthoquinone

C12H6O2

A polycyclic aromatic hydrocarbon derived from naphthalene that is insoluble in water, but soluble in alcohol. It is used as an intermediate for the manufacturing of dyes, pharmaceuticals and pesticides.

Acenaphthylene
A polycyclic aromatic hydrocarbon.
Acepromazine

C19H22N2OS

More commonly known as ACP it is a phenothiazine derivative antipsychotic drug.

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.
Acetaminophen

C8H9NO2

More commonly known as Paracetamol, a widely used over-the-counter analgesic.

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.
Acetoguanamine

C4H7N5

Used as a raw material for guanamine resins. It is used as a modifier and flexibilizer of formaldehyde resins and as a intermediate for pharmaceuticals.

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.
Aciclovir

C8H11N5O3

One of the most commonly-used antiviral drugs, it is primarily used for the treatment of herpes simplex virus infections.

Acid
Compound that gives off H+ ions in solution.
Acid Air
Alternative name for Hydrogen Chloride.
Acid Anhydride
Nonmetallic oxides or organic compounds that react with water to form acids.
Acid Error
A systematic error that occurs when glass pH electrodes are used in strongly acidic solutions.
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.
Acraldehyde
Alternative name for Acrolein.
Acridine

C13H9N

A colourless solid, was first isolated from coal tar. It is a raw material used for the production of dyes and some valuable drugs.

Acroleic Acid
Alternative name for Acrylic Acid.
Acrolein

C3H4O

the simplest unsaturated aldehyde. It has a piercing, disagreeable, acrid smell similar to that of burning fat.

Acrylamide

C3H5NO

A white odourless crystalline solid, soluble in water, ethanol, ether and chloroform.

Acrylic
Synthetic resin made from acrylic acid or a derivative thereof; acrylics possess the property of transparency and offer flame resistance.
Acrylic Acid

C3H4O2

The simplest unsaturated carboxylic acid with a vinyl group at the a-carbon position and a carboxylic acid terminus.

Acrylic Aldehyde
Alternative name for Acrolein.
Acrylonitrile

C3H3N

Pungent-smelling colourless liquid that often appears yellow due to impurities. It is an important monomer for the manufacture of useful plastics.

Acryloyl Chloride

C3H3ClO

A clear, light yellow, flammable liquid with an acrid smell.

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.
Adakane 12
Another name for Dodecane.
Adamantane

C10H16

A colourless, crystalline compound with a camphor-like odour. It is a cycloalkane and also the simplest diamondoid.

Addition Reaction
A chemical reaction in which two atoms or groups of atoms are added across a double bond.
Additive
A material added to another, usually in small amounts, to impart or enhance desirable properties or to suppress undesirable properties.
Adhesive Tape
A tape with a sticky substance on one side.
Adipic Acid
White crystalline solid used in the manufacture of nylon.
Adipoyl Chloride

C6H8Cl2O2

A hazardous chemical that evolves HCl when reacted with water. Can be reacted with hexamethylene diamine to form nylon.

Adipoyl Dichloride
Alternative name for Adipoyl Chloride.
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.
Adsorbtion Indicator
A substance that indicates an excess of a reactant in a precipitation reaction.
Adulterants
Chemical impurities or substances that by law do not belong in a food, or pesticide.
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.
Aeration Tank
A chamber used to inject air into water.
Aerial Acid
An old name for carbon dioxide.
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.
Alanine

C3H7NO2

An a-amino acid. It plays a key role in glucose-alanine cycle between tissues and liver.

Alcian Blue

C56H68Cl4CuN16S4

A phthalocyanine dye that contains copper.

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.
Aldosterone

C21H28O5

A hormone that causes the tubules of the kidneys to retain sodium and water.

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 Battery
A storage battery which uses an alkaline electrolyte.
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.
Alkaline Error
A systematic error that occurs when glass electrodes are used to read the pH of an extremely alkaline solution.
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
A molecular fragment derived by removing a methyl hydrogen from propene.
Allyl Alcohol
Used in the manufacture of resins and many pharmaceuticals this is a colourless pungent liquid.
Allyl Aldehyde
Alternative name for Acrolein.
Almond Artificial Essential Oil
Alternative name for Benzaldehyde.
AlN
Chemical formula for Aluminium Nitride.
Alpha Radiation
A stream of alpha particles. Alpha rays rapidly dissipate their energy as they pass through materials, and are far less penetrating than beta particles and gamma rays.
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 Ion
NH4+ is a cation formed by neutralization of ammonia, which acts as a weak base.
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.
Amphoteric
A substance that can act as either an acid or a base in a reaction.
AMU
Defined as one twelfth of the mass of the most abundant isotope of carbon (12C)
Amyl Nitrite

C5H11NO2

Employed medically to treat heart diseases such as angina and also to treat cyanide poisoning. It is also used as an inhalant drug that induces a brief euphoria.

Amylopectin
A form of starch made of glucose molecules linked in a branching pattern.
Amylose
A form of starch made of long, unbranched chains of -D-glucose molecules.
Anaerobic
Occurring in the absence of air or oxygen.
Analyte
The sample constituent whose concentration is sought in a chemical analysis.
Angelic Acid

C5H8O2

A monocarboxylic unsaturated organic acid found in Angelica Archangelica as well as other plants.

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.

Antioxidant
Compounds that slow oxidation processes that degrade foods, fuels, rubber, plastic, and other materials.
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.
Aquatic Ecotoxicity
The study of how chemicals affect the water environment and the organisms living there.
Aqueous Solubility
The maximum concentration of a chemical that will dissolve in pure water at a reference temperature.
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.
Arginine

C6H14N4O2

A semiessential or conditionally essential amino acid in mammals.

Argon
An inert gas that makes up about 1% of the atmosphere.
Aromatic
Aromatic compounds have strong, characteristic odors.
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.
Asbestosis
Fibrosis of the lungs caused by inhalation of asbestos fibres.
Ash
The mineral content of a product remaining after complete combustion.
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 Nucleus
A tiny, incredibly dense positively charged mass at the heart of the atom - normally abbreviated Nucleus.
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 Radius
One half the distance between nuclei of atoms of the same element, when the atoms are bound by a single covalent bond or are in a metallic crystal.
Atomic Theory
An explanation of chemical properties and processes that assumes that tiny particles called atoms are the ultimate building blocks of matter.
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.
Autoprotolysis
Transfer of a hydrogen ion between molecules of the same substance.
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.
Average Bond Enthalpy
Average enthalpy change per mole when the same type of bond is broken in the gas phase for many similar substances.
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.
BaCO3
Chemical formula for Barium Carbonate.
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.
Balanced Equation
A description of a chemical reaction that gives the chemical formulas of the reactants and the products of the reaction, with coefficients introduced so that the number of each type of atom and the total charge is unchanged by the reaction.
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 Carbonate

BaCO3

Chemical used in rat poison, bricks, ceramic glazes and cement.

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.
Base Oil
A liquid having a suitable boiling range and viscosity for use in lubricating oils.
BaSO4
Chemical formula for Barium Sulphate.
Bath Metal
A cheap bronze made with 21 parts copper and 5 parts zinc. The same as pinchbeck.

Battery
A device for converting chemical energy into electrical energy.
Battery Acid
A solution of approximately 6M sulfuric acid used in the lead storage battery.
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.
Benzoin

C14H12O2

An organic compound consisting of an ethylene bridge flanked by phenyl groups and with a hydroxyl and a ketone functional group. It comes as off-white crystals, with a light camphor odor.

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.
Bidentate
A ligand that has two "teeth" or atoms that coordinate directly to the central atom in a complex.
Bifunctional Monomer
A monomer unit that has two active bonding positions.
Bihexyl
Another name for Dodecane.
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.
Blind Reference Oil
A reference oil, the identity of which is unknown by the test facility.
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.

Butene

C4H8

A colourless gas that is present in crude oil as a minor constituent in quantities that are too small for viable extraction.

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.
C10H16
Chemical formula for Adamantane.
C10H22
Chemical formula for Decane.
C11H24
Chemical formula for Undecane.
C12H10
Chemical formula of Acenaphthene.
C12H10N2
Chemical formula for Azobenzene.
C12H26
Chemical formula for Dodecane.
C12H6O2
Chemical formula for Acenaphthoquinone.
C12H8
Chemical formula for Acenaphthylene.
C13H9N
Chemical formula for Acridine.
C14H10
Chemical formula for Anthracene.
C14H12O2
Chemical formula for Benzoin.
C14H8O
Chemical formula for Anthraquinone.
C15H24
Chemical formula for Zingiberene.
C16H32
Chemical formula for Cetene.
C19H22N2OS
Chemical formula for Acepromazine.
C20H30O2
Chemical formula for Abietic Acid.
C21H28O5
Chemical formula for Aldosterone.
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.
C3H3ClO
Chemical formula for Acryloyl Chloride.
C3H3N
Chemical formula for Acrylonitrile.
C3H4O
Chemical formula for Acrolein.
C3H4O2
Chemical formula for Acrylic Acid.
C3H5N3O9
Chemical formula for Nitroglycerine.
C3H5NO
Chemical formula for Acrylamide.
C3H6
Chemical formula for Propene.
C3H6O
Chemical formula for acetone.
C3H6O2
Chemical formula for Methyl Acetate.
C3H7NO2
Chemical formula for Alanine.
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.
C56H68Cl4CuN16S4
Chemical formula for Alcian Blue.
C5H11NO2
Chemical formula for Amyl Nitrite.
C5H11OH
Chemical formula for Pentanol.
C5H12
Chemical formula for pentane.
C5H8O2
Chemical formula for Angelic Acid.
C60
Buckminsterfullerene formed from 60 carbon atoms.
C6H10O4
Chemical formula for Adipic Acid.
C6H14
Chemical formula for Hexane.
C6H14N4O2
Chemical formula for Arginine.
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.
C6H8Cl2O2
Chemical formula for Adipoyl Chloride.
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.
C8H11N5O3
Chemical formula for Aciclovir.
C8H18
Flammable liquid compounds found in petroleum and natural gas.
C8H8O
Chemical formula for Acetophenone.
C8H9NO2
Chemical formula for Acetaminophen.
C8H9ON
Chemical formula for Acetanilide.
C9H20
Chemical formula for Nonane.
Ca
Calcium is one of the most abundant metal elements on Earth (41000 ppm).
CaC2
Chemical formula for Calcium Carbide.
CaCl2
Chemical formula for Calcium Chloride
CaCO3
Chemical formula for Calcium Carbonate.
Cadmium
A white metallic element.
Cadmium Oxide
Commonly used in glasses, plastics, ceramics and porcelain enamels as a coloring agent for reds, oranges, and yellows.

Cadmium Sulphate

CdSO4

Colourless, odourless crystals that are freely soluble.

Cadmium Sulphide

CdS

Found as the mineral greenockite, it is used together with selenium to produce strong reds and yellows.

Caesium
A soft metal which is often liquid at room temperature due to its relatively low melting point (28.5°C).
Caesium Bromide

CsBr

White crystalline solid.

Caesium Chloride

CsCl

White crystalline solid.

Caesium Fluoride

CsF

White crystalline solid.

Caesium Hydride

CsH

White crystalline solid.

Caesium Iodide

CsI

White crystalline solid.

Caesium Oxide

Cs2O

Yellow to orange crystalline solid.

Caesium Peroxide

Cs2O2

Yellow crystalline solid.

Caesium Sulphide

Cs2S

White to pale yellow crystalline solid.

Caesium Superoxide

CsO2

Yellow to orange crystalline solid.

Caffeine
A substance found in tea, coffee, and cola that acts as a stimulant. It is extremely soluble in supercritical fluid carbon dioxide and somewhat soluble in water; aqueous solutions of caffeine quickly break down.

Calamine Brass
Brass produced by a particular alloying technique using calamine (a zinc ore) rather than metallic zinc.

Calcination
A high-temperature reaction whereby one solid material dissociates to form a gas and another solid.
Calcium
One of the most abundant metal elements on Earth (41000 ppm).
Calcium Carbide

CaC2

Usually formed by fusing lime and hard coal in a furnace.

Calcium Carbonate

CaCO3

A white insoluble solid, occuring naturally as chalk, limestone, marble and calcite.

Calcium Chloride

CaCl2

Absorbs moisture from the atmosphere and is used for drying gases.

Calcium Hypochlorite

CaCl(OCl)

More commonly known as bleaching powder.

Calcium Oxide

CaO

Also know as Quicklime.

Calcium Sulphate

CaSO4

Used to make plaster of paris and plaster.

Californium
A man-made element with an atomic number of 98.
Calomel
Another name for Mercury I Chloride.
Calutron
A device that separates isotopes by ionizing the sample.
CaO
Chemical formula for Calcium Oxide.
Carbide
The old abbreviated name for calcium carbide.
Carbohydrate
A class of organic compounds including sugars and starches.
Carbolic Acid
Also known as phenol, it is used as a strong disinfectant.
Carbon
Occurs naturally in two allotropic forms, namely graphite and diamond.
Carbon Bisulphide
Alternative name for Carbon Disulphide.
Carbon Dioxide
A heavy, colourless gas that is the fourth most abundant constituent of dry air, comprising 0.033% of the total.
Carbon Disulphide
Also known as Carbon Bisulphide used as a solvent in the vulcanization of rubber.
Carbon Hydride Nitride
Alternative name for Hydrogen Cyanide.
Carbon Monoxide
A colourless gas that is very poisonous as it combines with the haemoglobin in blood forming a stable compound so reducing the ability to carry oxygen.
Carbon Tetrachloride
Colourless liquid with a sweet smell used as a solvent.
Carbon Tetrafluoride
Alternative name for Tetrafluoromethane.
Carbonado
Carbon that has metamorphosed into its diamond phase but remains black.
Carbonate
An inorganic ion with a charge of -2, containing carbon bound directly to three oxygens in a in a flat triangular arrangement.
Carbonic Acid

H2CO3

A weak acid formed by carbon dioxide dissolved in water.

Carbonic Oxide
Old name for Carbon Monoxide.
Carboxamide

NH2CONH2

More commonly known as Urea, the main nitrogenous excretion of most animals. It has the distinction of being the first organic compound to have been made in a laboratory (1828). Urea is used in the manufacture of ammonia and carbon dioxide.

Carboxylic Acid
A compound with molecules containing a carboxylic acid group -COOH.
Carboy
A very large bottle.
Carburetted Hydrogen
Old name for Methane.
Carcinogens
Substances known to cause cancer.
Carotene
Carotene is an unsaturated hydrocarbon pigment found in many plants. Carotene is the basic building block of vitamin A.

CaSO4
Chemical formula for Calcium Sulphate.
Cassiterite
Dark coloured mineral that is an important ore of Tin.
Catalyst
Substance that speeds up a chemical process without actually changing the products of reaction.
Catalytic Converter
An air pollution abatement device that removes pollutants from motor vehicle exhaust, either by oxidizing them into carbon dioxide and water or reducing them to nitrogen.
Catalytic Cracking
The use of a catalyst to break down the molecules of the high boiling temperature fractions of crude oil.
Cathode
Electrode where electrons are gained (reduction) in redox reactions.
Cathodic Protection
A means of corrosion prevention.
Cations
Ion with a positive charge.
Cauk
Old name for Barium Sulphate.
Caustic Potash
Old fashioned name for Potassium Hydroxide.
Caustic Soda
Alternative name for Sodium Hydroxide.
Cavendish, Henry
English physicist and chemist, discovered hydrogen.
Cawk
Old name for Barium Sulphate.
CCl3F
Chemical formula for Trichlorofluoromethane.
CCl4
Chemical formula for Carbon Tetrachloride.
Cd
Cadmium is a white metallic element.
CdS
Chemical formula for cadmium sulphide.
CdSO4
Chemical formula for Cadmium Sulphate.
Ce
Cerium is a reactive grey metal and is one of the most abundant of the lanthanide group of metals.
Cellophane
Cellophane is a thin, transparent, waterproof, protective film that is used in many types of packaging.

Cellulose
A polysaccharide made of linked glucose molecules that strengthens the cell walls of most plants.

Cellulosic Ethanol
Ethanol made from agricultural refuse, grass, wood, municipal waste and a variety of feedstock, which is less expensive and more available than just corn.
Cement
A substance that can be used to build together aggregates of sand or stone into a cohesive structure. May be a single compound or a mixture. May be hydraulic set, air set or chemical set.
CeO2
Chemical formula for Cerium Oxide.
Ceramic
Inorganic, nonmetalllic products for which the interatomic bonding is predominantly ionic.
Ceric Oxide
Another name for Cerium Oxide.
Cerium
A reactive grey metal and is one of the most abundant of the lanthanide group of metals.
Cerium Oxide

CeO2

The oxide of the rare earth element cerium. Cerium oxide usually appears as a yellow powder. It is insoluble in water and moderately soluble in strong mineral acids. Used alone or together with other substances as a polishing agent for glass.

Cermet
A composite material consisting of a combination of ceramic and metallic materials.
Cerussite
Mineral form of Lead II Carbonate.
Cetane Index
A calculated value, derived from fuel density and volatility, giving a reasonably close approximation to cetane number.
Cetane Number
A percentage indicating the ignition quality of diesel fuels.
Cetene

C16H32

An oily hydrocarbon of the ethylene series, obtained from spermaceti.

Cf
Californium is a man-made element with an atomic number of 98.
CF4
Chemical formula for Tetrafluoromethane.
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.
CH3OH
A colourless liquid also known as methyl alcohol.
CH4
The chemical formula for methane, the first alkane.
CH4O
Chemical formula for Methyl Alcohol.
Chalk
Common form of Calcium Carbonate.
Change of State
The change in a substance between solid and liquid or between liquid and gas.
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.
Charcoal
Used to describe different forms of carbon. Formed by heating vegetable or animal matter in the absence of air.
Charged
Possessing a net negative or positive charge.
CHCl3
Chemical formula for chloroform.
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 Energy
Energy stored in the bonds of atoms and molecules eg coal, petrol, biomass.
Chemical Equation
A compact notation for describing a chemical change.
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 Set Cement
A cement that sets through reaction or precipitation.
Chemical Stability
The tendency of a substance or mixture to resist chemical change.
Chemiluminescence
A chemical reaction that releases energy as electromagnetic radiation.
Chile Nitre
Another name for Sodium Nitrate.
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.
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.
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.

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 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.
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.
Cl
Chlorine is a greenish yellow gas and second in the halogen group.
Cm
Curium is a man-made radioactive element.
CNG
Abbreviation of Compressed Natural Gas.
Co
Cobalt is a hard, grey metal which is ferromagnetic.
CO
Chemical formula for Carbon Monoxide.
CO2
Chemical formula for Carbon Dioxide.
Co2O3
Chemical formula for Cobalt III Oxide.
Coal
A fossil fuel which is made mostly of carbon. It is formed from plants that grew around 150 million years ago.

Coal Tar
A dark brown to black cementitious material produced by the destructive distillation of bituminous coal.

Cobalt
A hard, grey metal which is ferromagnetic.
Cobalt Dichloride
Alternative name for Cobalt II Chloride.
Cobalt II Bromide

CoBr2

Green crystals, used as a catalyst in the oxidation of some organic compounds.

Cobalt II Chloride

CoCl2

Used as an indicator for water as there is a dramatic colour change from CoCl2 which is blue to CoCl2·6H2O which is a deep rose colour.

Cobalt II Nitrate

Co(NO3)2

A red crystalline solid with high solubility of cobalt nitrate makes it a common source of cobalt in metal-organic frameworks and polymers. Deliquescent in moist air.

Cobalt II Oxide

CoO

Olive green to red crystals or greyish or black powder used in ceramics to create blue coloured glazes.

Cobalt III Oxide

Co2O3

A black substance obtained by adding cobalt II nitrate to an aqueous solution of sodium hypochlorite.

Cobalt Monoxide
Alternative name for Cobalt II Oxide.
Cobalt Sesquioxide
Alternative name for Cobalt III Oxide.
Cobalt Trioxide
Alternative name for Cobalt III Oxide.
Cobaltic Oxide
Alternative name for Cobalt III Oxide.
Cobaltous Chloride
Alternative name for Cobalt II Chloride.
Cobaltous Monoxide
Alternative name for Cobalt II Oxide.
Cobaltous Nitrate
Alternative name for Cobalt II Nitrate.
Cobaltous Oxide
Alternative name for Cobalt II Oxide.
CoBr2
Chemical formula for Cobalt II Bromide.
CoCl2
Chemical formula for Cobalt II Chloride.
Coke
A hard, dry substance containing carbon that is produced by heating bituminous coal to a very high temperature in the absence of air.

Colligative Properties
Properties of a solution that depend only on the number of particles dissolved in it, not the properties of the particles themselves.
Collision Frequency
The average number of collisions that a molecule undergoes each second.
Collision Theory
A theory that explains reaction rates in terms of collisions between reactant molecules.
Colloid
A heterogeneous mixture composed of tiny particles suspended in another material.
Columbium
A name sometimes given to Niobium, a platinum-gray, ductile metal with brilliant luster that is used in alloys, especially stainless steels.
Column Chromatography
A method for separating mixtures.
Columnar Structure
Coarse structure of parallel columns of grains.
Combustible
Substance that can easily be set on fire and that will burn readily or quickly. Flammable.
Combustion Reaction
The vigorous and exothermic reaction that takes place between certain substances, particularly organic compounds, and oxygen.
Common Salt
Sodium Chloride.
Complex Ion
An ion formed by combination of simpler ions or molecules.
Complexing Agent
A ligand that binds to a metal ion to form a complex.
Complexometric Titration
A titration based on a reaction between a ligand and a metal ion to form a complex.
Component
An element or chemical compound that helps make up a material system.
Compound
A pure substance which contains two or more different elements chemically bonded together in stoichiometric proportions.
Compressed Natural Gas
Natural gas compressed to a volume and density that is practical as a portable fuel supply.
Computational Chemistry
A branch of chemistry concerned with the prediction or simulation of chemical properties, structures, or processes using numerical techniques.
CoN2O6
Chemical formula for Cobalt II Nitrate.
Concentrate
To increase the amount of substance present in a unit amount of mixture.
Concentration
The amount of substance in a specified space.
Concentration Cell
A voltaic cell in which both compartments contain the same components, but at different concentrations.
Concrete
Building material made from cement, sand, stone and water.

Condensation Polymerization
The formation of polymers by an intermolecular reaction involving at least two monomer species.
Congruent Transformation
A transformation of one phase to another that does not involve any change in composition.
Conjugate Acid
A substance which can lose a H+ ion to form a base.
Conjugate Base
A substance which can gain a H+ ion to form an acid.
Constantan
An alloy of 40% nickel and 60% copper, with a high volume resistivity and almost negligible temperature coefficient. Used with copper in T-type thermocouples.

Contaminant
Any foreign or unwanted substance that can have a negative effect on system operation, life or reliability.
Continuous Spectrum
A plot of the relative absorbance or intensity of emitted light vs. wavelength or frequency that shows a smooth variation, rather than a series of sharp peaks or bands.
CoO
Chemical formula for Cobalt II Oxide.
COOH
Carboxylic acid group.
Coordination Number
The number of atomic or ionic nearest neighbours.
Copolymer
A polymer that consists of two or more dissimilar mer units in combination along its molecular chains.
Copper
Noted for being ductile and having good electrical and thermal conductivity. It forms the basis of a number of alloys.
Copper I Bromide

CuBr

Yellowish green or white crystalline solid.

Copper I Chloride

CuCl

White crystalline solid. Turns green in moist air.

Copper I Iodide

CuI

White crystalline solid.

Copper I Oxide

Cu2O

A red powder.

Copper I Sulphide

Cu2S

Yellow, red, or brown crystalline solid.

Copper II Bromide

CuBr2

Black crystalline solid. Reacts violently with potassium.

Copper II Carbonate

CuCO3

Green or blue powder forming most of the patina one sees on weathered brass, bronze, and copper. Used as a pigment.

Copper II Hydroxide

Cu(OH)2

Used as a fungicide.

Copper II Oxide

CuO

A black-brown crystalline solid.

Copper II Sulphide

CuS

Blue-black or black crystalline solid.

Copper Sulphate

CuSO4

A water soluble salt used in copper plating.

Copperas
The mineral form of Iron II Sulphate.
Core Electron
Electrons occupying completely filled shells under the valence shell.
Cork
Outer waterproof layer covering most trees and shrubs. The cork material used in flooring and for it′s properties is from the tree Quercus Suber.

Corrosion
Deteriorative loss of a metal as a result of dissolution environmental reactions.
Corrosive
Having the power to dissolve. Can burn and destroy living tissue.
Corrosive Sublimate
Another name for Mercury II Chloride.
Coulombic Force
A force between charged particles, such as ions.
Covalent Bond
Describes the mutual electrostatic attraction of two or more adjacent nuclei for a shared pair of electrons which occupy the same molecular energy level.
Covalent Radius
The radius of atoms obtained from covalent bond lengths.
Cr
Chromium is a bright, blue/white metal with excellent corrosion resistance.
Cr2O3
Chemical formula for Chromium Oxide.
Cracking
The thermal decomposition of the molecules of high molecular mass organic compounds to produce molecules of compounds of lower molecular mass.
Critical Temperature
The temperature at the critical point.
CrO2
Chemical formula for Chromium Dioxide.
Crosslinked Polymer
A polymer in which adjacent linear molecular chains are joined at various positions by covalent bonds.
Crown Glass
A silicate glass containing oxides of sodium and potassium, used in compound lenses and spectacles; harder than flint glass, with low index and low dispersion.

Crown Gold
2 carats of alloy (usually copper sometimes silver) and 22 carats of gold so called from the gold crown of 1526 which used this alloy.

Cryogenic Gas
A gas that has been liquified by lowering the temperature, usually to a temperature under about -100°C.
Crystal
A material in which the atoms are arranged in a definite geometric pattern.
Crystal Structure
For crystalline materials, the manner in which atoms or ions are arrayed in space. It is defined in terms of the unit cell geometry and the atom positions within the cell.
Crystal System
A scheme by which crystal structures are classified according to unit cell geometry.
Crystalline
The state of a solid material characterized by a periodic and repeating three-dimensional arrays of atoms, ions, or molecules.
Crystallite
A region within a crystalline polymer in which all the molecular chains are ordered and aligned.
Crystallization
Act or process of forming crystals or bodies by elements or compounds solidifying.
Crystals of Silver
Old name for Silver Nitrate.
Cs
A soft metal which is often liquid at room temperature due to its relatively low melting point (28.5°C).
CS2
Chemical formula for carbon disulphide.
Cs2O
Chemical formula for Caesium Oxide.
Cs2O2
Chemical formula for Caesium Peroxide.
Cs2S
Chemical formula for Caesium Sulphide.
CsBr
Chemical formula for Caesium Bromide.
CsCl
Chemical formula for Caesium Chloride.
CsF
Chemical formula for Caesium Fluoride.
CsH
Chemical formula for Caesium Hydride.
CsI
Chemical formula for Caesium Iodide.
CsO2
Chemical formula for Caesium Superoxide.
Cu
Copper is a reddish coloured metal which is malleable and ductile. It has excellent thermal and electrical conductivities and good corrosion resistance.
Cu2O
Chemical formula for Copper I Oxide.
Cu2S
Chemical formula for Copper I Sulphide.
Cubic Nitre
Name for the crystallised form of Sodium Nitrate.
CuBr
Chemical formula for Copper I Bromide.
CuBr2
Chemical formula for Copper II Bromide.
CuCl
Chemical formula for Copper I Chloride.
CuCO3
Chemical formula for Copper II Carbonate.
CuI
Chemical formula for Copper I Iodide.
Cunife
An alloy of copper, nickel, iron, and in some cases cobalt.

CuO
Chemical formula for Copper II Oxide.
Cupric Bromide
Old name for Copper II Bromide.
Cupronickel
An alloy of copper and nickel that is resistant to corrosion.

Cuprum
The old name for Copper and from where the chemical symbol Cu was derived.
Cure
To irreversibly polymerize a thermosetting plastic by subjecting it to a time-temperature profile.
Curium
Man-made radioactive element.
CuS
Chemical formula for Copper II Sulphide.
CuSO4
Chemical formula for Copper Sulphate.
Cyanocobolamin
Commonly known as vitamin B12.
Cyanoethene
Alternative name for Acrylonitrile.
Cyanogen
Colourless very poisonous gas that smells of bitter almonds.
Cycloalkanes
Saturated compounds containing only carbon and hydrogen atoms in which the carbon backbone forms a ring structure.
Cyclon
Alternative name for Hydrogen Cyanide.
D2O
Chemical formula for Heavy Water.
dalton
The atomic mass unit is sometimes called the dalton, after John Dalton.
Dalton, John
He developed atomic theory that accounts for the law of conservation of mass, law of definite proportions and law of multiple proportions.
Dalton′s Law of Partial Pressures
The total pressure of a mixture of gases, which do not interact chemically, is equal to the sum of the partial pressures.
Damps
Any dangerous vapours in caves, mines etc.
Darcets Alloy
A low melting point alloy.

Debye
Unit of dipole moment.
Decane

C10H22

Decane is one of the components of petrol. Like other alkanes, it is nonpolar and therefore will not dissolve in polar liquids such as water.

Decantation
To a separate the supernatant liquid from a solid precipitate by pouring the liquid off, being careful that all of the solid remains in the vessel.
Decoction
Continuous application of boiling heat to a reaction mixture.
Decompounded
Doubly compounded, or composed of three or more substances.
Decrepitation
Rapid physical decomposition of some crystals when heated. Characterized by a crackling noise.
Deflagration
To cause a substance to burn rapidly, with flame.
Degas
Removing air from a liquid, usually by ultrasonic or vacuum methods.
Degenerate Orbital
A set of orbitals are said to be degenerate if they all have the same energy.
Degree of Polymerization
The average number of mer units per polymer chain molecule.
Dehydrator
A separator that removes water from the system fluid.
Deliquescence
Deliquescent compounds absorb so much moisture from the air that they dissolve.
Deliquium
Change of salt from a solid to a fluid state by contact with air only.
Denatured Alcohol
Poison is added to industrial ethanol so that the tax is not charged for industrial usage.
Dephlegmation
To remove water from a solution, usually one of an acid or alcohol.
Dephlogisticated Air
An old name for oxygen.
Depuration
To free from impurities, purify.
Desalination
Removal of dissolved salts from seawater.
Desiccator
A sealed container in which a drying agent is used to dry material that contains water.
Desquamation
The process of removing scaly crusts which form on a surface.
Detonation
Any rapid chemical reaction accompanied by noise and often heat and light, e.g., explosions.
Deuterium
An isotope of hydrogen that contains one neutron and one proton in its nucleus.
Devitrification
The process in which a glass (noncrystalline or vitreous solid) transforms to a crystalline solid.
Dialuminium Hexachloride
Alternative name for Aluminium Chloride.
Dialuminium Trisulphide
Alternative name for Aluminium Sulphide.
Dialysis
The separation of components in a mixture by passing them across a semipermeable membrane.
Diamond
A crystalline form of carbon, made of a network of covalent, tetrahedrally bound carbon atoms.
Diastereomers
Optical isomers that are not mirror images of each other.
Diatomic Molecules
Molecules composed of two atoms eg CO.
Diazotization
A reaction that converts an -NH2 group connected to a phenyl ring to a diazonium salt.
Dicaesium Oxide
Old name for Caesium Oxide.
Dicaesium Peroxide
Old name for Caesium Peroxide.
Dicaesium Sulphide
Old name for Caesium Sulphide.
Dichlorodiethyl Sulphide

(CH2CH2Cl)2S

Oily gas used in warfare. Also known as mustard gas or yperite.

Dichloromethane

CH2Cl2

Organic solvent often use to extract organic substances from samples.

Dicobalt Trioxide
Alternative name for Cobalt III Oxide.
Didymium
A mixture of praseodymium and neodymium believed to be an element until 1885.
Diffusion
The mixing of two substances caused by random molecular motions.
Diffusion Rate
The number of randomly moving molecules that pass through a unit area per second.
Dihexyl
Another name for Dodecane.
Dihydrogen Monoxide
More commonly known as water.
Dihydrogen Selenide
Old name for Hydrogen I Selenide.
Dilatometer
A device for measuring volume changes.
Dilithium Oxide
Old name for Lithium I Oxide.
Dilithium Peroxide
Old name for Lithium I Peroxide.
Dilute
Having a relatively low concentration.
Dilution
Adding solvent to a solution to lower its concentration.
Dimercury Dichloride
Another name for Mercury I Chloride.
Dimethyl Ketone
Also known as acetone.
Dimethylbenzenes
Alternatively known as Xylol.
Dipole-Dipole Interaction
Electrostatic attraction between oppositely charged poles of two or more dipoles.
Dipotassium Oxide
Old name for Potassium Oxide.
Dipotassium Peroxide
Old name for Potassium Peroxide.
Discontinuity
A break in sequence or continuity of anything.
Disilver Sulphide
Old name for Silver Sulphide.
Disinfectant
A substance that kills or stops the growth of microbes.
Dislocation
A linear crystalline defect around which there is an atomic misalignment.
Disodium Oxide
Old name for Sodium Oxide.
Dispersant
An additive that reduces deposits on oil-wetted surfaces primarily through suspension of particles.
Dissociation
Breaking down of a compound into its components.
Dissolve
To mix a solid and a liquid to form a solution.
Dissolved Oxygen
The amount of oxygen dissolved in a solvent (usually water).
Distillate
The vapour collected and condensed from a distillation.
Distillation
A process used to separate a liquid from a solution.
Distillation Per Ascensum
Distillation with the collecting vessel above the heated vessel.
Distillation Per Decensum
Any distillation where the collecting vessel is below the heated vessel.
Distillation Per Obliquium
Distillation in a retort used for substances of relatively low vapor pressure and other properties that make distillation difficult.
Distillation with Addition
Adding some substance prior to distillation that will aid the process.
Disulfane
Old name for Hydrogen Persulphide.
Divalent
Binds to two other things: atoms, molecules, ions, or electrons.
Divalent Anion
An ion with a charge of -2.
Divalent Cation
An ion with a charge of +2.
Dodecane

C12H26

A thick, oily liquid of the paraffin series. It is used as a solvent, distillation chaser and is also the average component of diesel fuel.

Doping
The intentional alloying of semiconductor materials with controlled concentrations of donor or acceptor impurities
Double Bond
When an atom is bonded to another atom by two sets of electron pairs.
Double Displacement
A reaction in which two reactants trade fragments.
Dry Bulb Thermometer
A thermometer used to measure the ambient temperature.
Dry Cell
A electrolytic cell also known as a Leclanché cell that uses a moist paste rather than a liquid as an electrolyte.
Dulcification
Any process in which a caustic substance is rendered less corrosive.
Duodecane
Another name for Dodecane.
Dy
Dysprosium is a silvery metal of the lanthanide group. It is relatively stable in air, reacts violently with water and dissolves in acids.
Dynamic Equilibrium
Equilibrium which includes inertial forces.
Dynamite
A blasting explosive, based on nitroglycerine, but much safer to handle than nitroglycerine alone.
Dysprosium
A silvery metal of the lanthanide group. It is relatively stable in air, reacts violently with water and dissolves in acids.
E10 Ethanol
Ethanol mixture that contains 10% ethanol, 90% unleaded gasoline.
E85
Refers to a fuel blend of 85 percent ethanol and 15 percent gasoline.
E85 Ethanol
Refers to a fuel blend of 85 percent ethanol and 15 percent gasoline.
Ebulliometry
Determination of average molecular weight of a dissolved substance from the boiling point elevation of the solution.
Ebullition
The agitating, bubbling action of a liquid that is undergoing rapid, active boiling.
Effective Nuclear Charge
The nuclear charge experienced by an electron when other electrons are shielding the nucleus.
Efflorescent
Efflorescent substances lose water of crystallization to the air.
Effusion
Movement of gas molecules through a small opening.
Einsteinium
An artificial radioactive element found in the debris of an H bomb.
Elastomer
A polymeric material that may experience large and reversible elastic deformations.
Electric Dipole Moment
A measure of the degree of polarity of a polar molecule.
Electrochemistry
The study of the interchange of chemical and electrical energy.
Electrodes
Device that moves electrons into or out of a solution by conduction.
Electrokinetic Potential
Electric potential across all phase boundaries between solids and liquids, also known as the Zeta Potential.
Electrolysis
Changing the chemical structure of a compound using electrical energy.
Electrolyte
A substance that dissociates fully or partially into ions when dissolved in a solvent, producing a solution that conducts electricity.
Electrolytic cell
A cell that uses electrical energy to produce a chemical change that would otherwise not occur spontaneously.
Electromotive Series
The electrode potential of a material according to decreasing tendency to release electrons with hydrogen as zero.
Electron Affinity
The measure of an atom′s tendency to gain an electron.
Electron Shell
A group of electrons which have a common energy level that forms part of the outer structure of an atom.
Electropositive
For an atom, having a tendency to release valence electrons.
Electrostatic Interactions
Attractions between opposite charges or repulsions between like charges that grow stronger as the charges become closer to each other.
Electrum
An alloy of 75% gold and 25% silver along with small quantities of other metals such as copper.

Element
A pure substance which cannot be broken down into simpler substances by chemical means.
Emollient
A substance added to a formulation that gives it softening ability.
Empirical Law
A law strictly based on experiment, which may lack theoretical foundation.
Emulsion
A colloid formed from tiny liquid droplets suspended in another, immiscible liquid. E.g. Milk.
Enantiomers
Stereoisomers that are nonsuperimposable complete mirror images of each other.
Endergonic
Refers to a reaction for which the free energy of the system increases.
Endothermic
Reaction that absorbs heat from its surroundings as the reaction proceeds.
Energy Density
Characteristic parameter of a battery/electrical power source indicating the amount of electrical energy stored per unit weight or volume.
Enthalpy
Change in heat.
Enthalpy of Atomization
The change in enthalpy that occurs when one mole of a compound is converted into gaseous atoms.
Enthalpy of Combustion
The amount of energy released in burning completely an amount of substance.
Enthalpy of Fusion
The enthalpy change that occurs to melt a solid at its melting point.
Enthalpy of Hydration
The enthalpy change associated with placing gaseous molecules or ions in water.
Enthalpy of Neutralization
The heat released by an acid-base neutralization reaction running at constant pressure.
Enthalpy of Reaction
The heat absorbed or released by a chemical reaction running at constant pressure.
Enthalpy of Solution
The enthalpy change associated with dissolving a solute in a solvent.
Enthalpy of Sublimation
The change in enthalpy when one mole of solid vaporizes to form one mole of gas.
Enthalpy of Vaporization
The change in enthalpy when one mole of liquid evaporates to form one mole of gas.
Entropy
Measure of the disorder of a system.
Enzyme
Protein or protein-based molecules that speed up chemical reactions occurring in living things.
Equivalence Point
Occurs when the moles of acid equal the moles of base in a solution.
Er
Erbium is a silvery grey metal that is a member of the lanthanide group of elements.
Erbium
A silvery grey metal that is a member of the lanthanide group of elements.
Errors
No measurement is exact, they all contain some degree of errors.
Es
Einsteinium artificial radioactive element found in the debris of an H bomb.
Essential Oil
Any oil that smells the same as the vegetable from which it was obtained and has a low boiling point.
Ester
Compound formed by the reaction between an alcohol and an acid, with the elimination of water.
Ethanal
Also known as acetaldehyde, it is a colourless fruity smelling liquid that with further oxidation forms acetic acid.
Ethanamide
Also known as Acetamide.
Ethane

C2H6

Second member of the alkane series, a colourless, odourless gas.

Ethanenitrile
Also known as Acetonitrile.
Ethanoic Acid
Alternative name for Acetic Acid.
Ethanol

C2H5OH

Prepared by the fermentation of sugar.

Ethanol E10
Ethanol mixture that contains 10% ethanol, 90% unleaded gasoline.

Ethanol E85
Refers to a fuel blend of 85 percent ethanol and 15 percent gasoline.

Ethanoyl Chloride
Also known as Acetyl Chloride.
Ethene
Alternative name for Chloroform.
Ethyl
The monovalent radical -C2H5
Ethyl Acetate

CH3COOCH2CH3

A flammable liquid with a fruity odour, used in flavourings and as a solvent.

Ethyl Bromide
Alternative name for Bromoethane.
Ethyl Chloride
Alternative name for Chloroethane.
Ethylamine

CH3CH2NH2

Widely used in chemical industry and organic synthesis, it has a strong ammonia-like odor.

Ethylene
Also known as Ethene this is a colourless inflammable gas with a sweet smell used as an anaesthetic and in the manufacture of polythene.
Ethylene Aldehyde
Alternative name for Acrolein.
Ethylenecarboxylic Acid
Alternative name for Acrylic Acid.
Ethyne
Also known as Acetylene, used for welding as the flame temperature is roughly 3300°C when burnt with oxygen.
Eu
A europium is a ductile silvery metal which reacts rapidly with air and water.
Europium
A ductile silvery metal which reacts rapidly with air and water.
Eutectic Alloy
An alloy that changes directly from a solid to a liquid with no plastic or semiliquid state.
Eutectic Mixture
A mixture of two or more substances with melting point lower than that for any other mixture of the same substances.
Excitotoxin
An excitotoxin is a toxic molecule that stimulates nerve cells so much that they are damaged or killed.
Exergonic
Refers to a reaction for which the free energy of the system decreases.
Exothermic
Reaction that gives off heat to the environment.
Experimental Yield
The measured amount of product produced in a chemical reaction.
Extensive Properties
Properties which are dependent on the amount of the substance.
Extrinsic Semiconductor
A semi-conducting material for hich the electrical behavior is determined by impurities.
F
Fluorine is a pale greenish yellow gas that is the first in the halogen group.
Face Centred Cubic
Roughly 20% of the elements crystallize with face centred cubic structures.
Fatigue
An important mode of failure of engineering components subjected to dynamic stresses.
Fe
Iron is one of the most abundant metallic elements (41000 ppm) and probably one of the most important, being used on the largest scale of any metal.
Fe2O3
Chemical formula for Iron III Oxide.
FeCl2
Chemical formula for Iron II Chloride.
FeCl3
Chemical formula for Iron III Chloride.
FeO
Chemical formula for Iron II Oxide.
Fermium
A man-made element with an atomic number of 100.
Ferric Oxide
Old name for Iron III Oxide.
Ferroelectric
A dielectric material that may exhibit polarization in the absence of an electric field.
Ferromagnetism
Permanent and large magnetizations found in some metals (e.g., Fe, Ni, and Co), which result from the parallel alignments of neighboring magnetic moments.
Ferrous Chloride
Old name for Iron II Chloride.
Ferrous Oxide
Old name for Iron II Oxide.
Ferrous Sulphide
Old name for Iron Sulphide.
Ferrum
Latin for iron, hence the symbol Fe.
FeS
Chemical formula for Iron Sulphide.
FeS2
Chemical formula for Iron II Sulphide.
FeSO4
Chemical formula for Iron II Sulphate.
Fibre
Any material that has been drawn into a cylinder with a length-to-diameter ratio greater than about ten.
Fields Metal
A low melting point alloy. 51% Indium, 32.5% Bismuth, and 16.5% Tin.
A non-toxic replacement for Wood's Metal.
Filler
An inert foreign substance added to a matrix to improve or modify its properties.
Fire Air
An old name given to pure oxygen.
Fire Damp
The gases found naturally in coal are a mixture of methane and other hydrocarbons. Given the name as they are highly combustible when mixed with air.
First Order Reaction
The sum of concentration exponents in the rate law for a first order reaction is one. Many radioactive decays are first order reactions.
Flame Test
A test to identify some metals, e.g. with sodium the flame turns orange.
Flammable
Substance that can easily be set on fire and that will burn readily or quickly.
Flash Point
The temperature when vapour pressure of a substance becomes high enough to allow the air/vapour layer over the substance to be ignited.
Flint Glass
An optical glass with higher dispersion and higher refractive index than crown glass; a heavy, brilliant glass, softer than crown glass.

Fluorescence
The property of a material whereby it emits visible light when it is illuminated by ultraviolet light.
Fluorine
A pale greenish yellow gas that is the first in the halogen group.
Fluorotrichloromethane
Alternative name for Trichlorofluoromethane.
Fm
Fermium is a man-made element with an atomic number of 100.
Foam
A colloid in which bubbles of gas are suspended in a solid or liquid.
Fools Gold
Name given to Iron II Sulphide due to its colour and texture.
Formaldehyde

H2CO

Used widely by industry to manufacture building materials and numerous household products. It is also a by-product of the incomplete combustion of carbo containing materials.

Formic Acid
Another name for Methanoic Acid.
Formic Anammonide
Alternative name for Hydrogen Cyanide.
Formonitrile
Alternative name for Hydrogen Cyanide.
Formyl Trichloride
Alternative name for Chloroform.
Formylic Acid
Another name for Methanoic Acid.
Fossil Fuel
A fuel such as coal, oil or natural gas that was formed through the decomposition of ancient plant and animal life.
Fr
Francium is the heaviest alkali metal with no stable isotopes.
Francium
The heaviest alkali metal with no stable isotopes.
Freeze
To change from a liquid to a solid by cooling.
Frenkel Defect
In an ionic solid, a cation-vacancy and cation-interstitial pair.
Freon-10
Alternative name for Carbon Tetrachloride.
Freon-11
Alternative name for Trichlorofluoromethane.
Freon-14
Alternative name for Tetrafluoromethane.
Fuel
Any substance burned for heat or power.
Fuel Cell
A device that converts the chemical energy obtained from a redox reaction directly into electrical energy.
Fullerene
A form of carbon consisting of 60 carbon atoms bound together to make a roughly spherical buckyball.
Fulmination
Any very rapid reaction which produces heat, light, and noise - explosions.
Furanose Ring
A five-membered cyclic hemiacetal or hemiketal of a carbohydrate.
Fused Quartz
The glassy isotropic form of quartz.
Fused Silica

SiO2

The glassy isotropic form of quartz.

Ga
Gallium is one of four metals which can be liquid at room temperature
GAA
Abbreviation of Glacial Acetic Acid.
Gadolinium
A silvery white metal which is ductile and malleable. It is stable in a dry atmosphere but forms an oxide coating when exposed to moist air.
Galena
A Lead Sulphide and the most common ore of lead.
Gallium
One of four metals which can be liquid at room temperature.
Galvanic Cell
A cell in which chemical change is the source of electrical energy.
Galvanic Corrosion
Corrosion associated with the current of a galvanic cell consisting of two dissimilar conductors in an electrolyte or two similar conductors in dissimilar electrolytes.
Galvanic Couple
A pair of dissimilar conductors, commonly metals, in electrical contact.
Galvanic Current
The electric current that flows between metals or conductive nonmetals in a galvanic couple.
Gamma Iron
The face-centered cubic form of pure iron, stable from 910 to 1400°C.
Gas
Matter with no definite shape or volume.
Gas Constant
Molar Gas Constant, R = 8.31441 JK-1mol-1
Gasification
A process for converting materials such as coal, petroleum, or biomass, into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen.
Gay-Lussac, Joseph Louis
Developed the law of volumes concerning the combination of gases and discovered boron.
Gd
Gadolinium is a silvery white metal which is ductile and malleable. It is stable in a dry atmosphere but forms an oxide coating when exposed to moist air.
Ge
Germanium is a silvery white brittle metalloid member of the carbon group of elements. Its physical properties being similar to those of silicon.
Geometric Isomer
Molecules that have the same molecular formula and bond connections, but distinctly different shapes.
German Silver
This describes a number of alloys that contain copper (25 to 50%), zinc (10 to 35%) and nickel (5 to 35%) within the limits given.
Germanium
A silvery white brittle metalloid member of the carbon group of elements. Its physical properties being similar to those of silicon.
Gibbs Free Energy
A function of the system related to Suniv. It is used to determine the spontaneity of a reaction.
Gibbsite
White crystalline mineral consisting of aluminum hydroxide; a constituent of bauxite and a source of alumina.
Glass
Transparent or translucent substance that is physically neither a solid or liquid. It is made by fusing certain types of sand (silica).
Glass Ceramic
A fine-grained crystalline material that was formed as a glass and subsequently devitrified (crystallized).
Glass Transition Temperature
The temperature at which, upon cooling, a noncrystalline ceramic or polymer transforms from a supercooled liquid into a rigid glass.
Glucose
A sugar. It is made by plants during photosynthesis.

Glue
Cement or adhesive that is used to fix two or more parts together.
Glycerol
Thick sweet liquid used in the manufacture of explosives.
Glycine

NH2CH2COOH

A naturally occurring aliphatic amino acid, found in large quantities in gelatin.

Gold
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.
Graphite
An amorphous form of carbon, made of carbon atoms bound hexagonally in sheets.

Green Vitriol
Hydrated Iron II Sulphate.
Greenockite
Mineral, main source of cadmium sulphide.

Group
A vertical column in the periodic table.
Guaranine
An alkaloid extracted from guarana, the same as Caffeine.
Gunmetal
This is a copper-tin alloy, similar to bronze, used where resistance to corrosion and/or wear required. Composition: 88% copper, 8% tin, 4% zinc.

Gunpowder
Any of several low-explosive mixtures.
Gy
An abbreviation of gray, the amount of energy actually absorbed in some material, and is used for any type of radiation and any material.
Gypsum
The old name for Calcium Sulphate.
H
Hydrogen is the least dense element. It has metallic and non-metallic properties.
H2C2O4
Chemical formula for Oxalic Acid.
H2CO
Chemical formula for Formaldehyde.
H2CO3
Chemical formula for Carbonic Acid.
H2O
Chemical formula for water
H2O2
Hydrogen peroxide.
H2S
Hydrogen sulphide.
H2Se
Chemical formula for Hydrogen I Selenide.
H2SO3
Chemical formula for Sulphurous Acid.
H2SO4
Chemical formula for Sulphuric Acid.
H2Te
Chemical formula for Hydrogen I Telluride.
H3PO4
Chemical formula for Phosphoric Acid.
ha
An abbreviation of hectare, a derived SI unit of area that is mainly used in agriculture to describe the area of fields.
Haber Process
An industrial process in which ammonia is manufactured by direct combination of its elements.
Hafnium
A silvery coloured, ductile metal which is found in all minerals containing zirconium.
Halide
A compound composed of two elements, one of which is a halogen (flourine, chlorine, bromine, iodine and astatine).
Halogen
Group of elements with similar bonding properties, consisting of flourine, chlorine, bromine, iodine and astatine.
Halon
Organic chemical compounds containing one or two carbon atoms, together with bromine and other halogens.
Hazard
The potential that the use of a product will result in an adverse effect on a person or the environment.
HCL
Hydrochloric acid.
HCL
Hydrogen chloride.
HCN
Chemical formula for Hydrogen Cyanide.
HCP
Abbreviation of Hexagonal Close Packed, a crystal structure found for some metals.
He
Helium is an inert gaseous element.
Heat of Combustion
The amount of energy released in burning completely an amount of substance.
Heat of Hydration
The enthalpy change associated with placing gaseous molecules or ions in water.
Heat of Neutralization
The heat released by an acid-base neutralization reaction running at constant pressure.
Heat of Reaction
The heat absorbed or released by a chemical reaction running at constant pressure.
Heat of Solution
The enthalpy change associated with dissolving a solute in a solvent.
Heat of Sublimation
The change in enthalpy when one mole of solid vaporizes to form one mole of gas.
Heat of Vaporization
The energy required to vaporize one mole of a liquid at a pressure of one atmosphere.
Heavy Metals
Metallic elements with high atomic weights can damage living things at low concentrations and tend to accumulate in the food chain.
Heavy Water

D2O

Water that contains 2H, rather than 1H. Heavy water is about 11% denser than ordinary water.

Helium
An inert gaseous element.
Helmholtz Free Energy
Energy released or absorbed in a reaction occurring reversibly at constant volume and temperature.
Hendecane
Another name for Undecane.
Hepatic Air
Old name for hydrogen sulphide.
Heptane

C7H16

An alkane hydrocarbon. A constituent of petroleum.

Hermetic
Sealing of an object so it is airtight.
Hess′s Law
In going from a particular set of reactants to a particular set of products, the enthalpy change is the same whether the reaction takes place in one step or a series of steps; in other words, enthalpy is a state function.
Heterocyclic Compounds
In chemistry, heterocyclic compounds are cyclic compounds in which the ring system of the molecule contains other elements than carbon.
Heterogeneous Catalysis
A form of catalysis in which the catalyst is in a different physical state than the reactants.
Hexagonal Close Packed
A crystal structure found for some metals.
Hexane

C6H14

Hexane isomers are largely unreactive, and are frequently used as an inert solvent in organic reactions because they are very non-polar.

Hf
Hafnium is a silvery coloured, ductile metal which is found in all minerals containing zirconium.
HF
Chemical formula for Hydrofluoric Acid.
Hg
The most common liquid metal at room temperature.
Hg2Cl2
Chemical formula for Mercury I Chloride.
HgCl2
Chemical formula for Mercury II Chloride.
HgO
Chemical formula for Mercury II Oxide.
HgS
Mercuric Sulphide, the ore of mercury. Occuring as red crystals.
HI
Chemical formula for Hydrogen Iodide.
HNO3
Chemical formula for Nitric Acid.
Ho
Holmium is a member of the lanthanide group with properties closely resembling those of erbium and dysprosium.
Holmium
A member of the lanthanide group with properties closely resembling those of erbium and dysprosium.
Homogeneous Catalysis
A form of catalysis in which the catalyst is in the same physical state as the reactants.
Homogeneous Mixture
A sample of matter consisting of more than one pure substance with properties that do not vary within the sample.
Homopolymer
A polymer having a chain structure in which all mer units are of the same type.
HRb
Chemical formula for Rubidium Hydride.
Hunds Rule
When electrons are put into orbitals having the same energy, degenerate orbitals, one electron is put into each orbital before putting a second electron into an orbital.
Hydrargyrum
The old name for Mercury and from where the chemical symbol Hg was derived.
Hydrate
A compound that has discrete water molecules combined with it.
Hydrated Beryllia
Alternative name for Beryllium Hydroxide.
Hydration
The combination of water and another substance to produce a single product.
Hydraulic Set Cement
A cement that sets through reaction with water.
Hydride
A compound containing a negatively charged hydrogen.
Hydrocarbon
A chemical containing only hydrogen and carbon.
Hydrochloric Acid

HCl

A solution of hydrogen chloride in water. Concentrated acid is a colourless, fuming, corrosive liquid.

Hydrochloride
Alternative name for Hydrogen Chloride.
Hydrocyanic Acid
A solution of Hydrogen Cyanide in water.
Hydrofluoric Acid

HF

Aqueous solution of hydrogen fluoride. Dissolves most metals and etches glass.

Hydrogen
The least dense element. It has metallic and non-metallic properties.
Hydrogen Arsenide

AsH3

Intensely poisonous colourless gas. Also known as Arsine.

Hydrogen Bonding
Strong type of intermolecular dipole-dipole attraction. Occurs between hydrogen and fluorine, oxygen or nitrogen.
Hydrogen Carboxylic Acid
Another name for Methanoic Acid.
Hydrogen Chloride
Dissolves in water to produce hydrochloric acid.
Hydrogen Cyanide

HCN

Colorless, very poisonous and highly volatile liquid.

Hydrogen I Nitride
Modern name for Ammonia.
Hydrogen I Selenide

H2Se

Colourless gas.

Hydrogen I Telluride

H2Te

Colourless gas.

Hydrogen Iodide

HI

Colourless gas.

Hydrogen Peroxide

H2O2

A colourless, viscous, unstable liquid compound of hydrogen and water with oxidising and reducing properties. Used for bleaching wool, silk, linens, furs and hair products since the 19th century. During the Second World War hydrogen peroxide was used as a propellant in V1 rockets and was subsequently also used as a propellant for submarines. Hydrogen peroxide is also used as a preservative and disinfectant and is used by archaeologists to dissolve clay from finds.

Hydrogen Persulphide

H2S2

Colourless liquid.

Hydrogen Sulphide
Poisonous and smells of rotten eggs.
Hydrogenation
A chemical reaction in which hydrogen is added to a compound.
Hydroiodic Acid
Alternative name for Hydrogen Iodide.
Hydrolysis
When water reacts with another substance and as a result the oxygen in water makes a bond with the substance.
Hydrophilic
A polar molecule or group that can form strong hydrogen bonds with water.
Hydrophobic
A nonpolar molecule or group that has little affinity for water.
Hydroquinone
A reducing agent used in photographic developers.

Hydroxy Group
An -OH group attached to an organic molecule.
Hydroxybutanedioic Acid

C4H6O5

An organic dicarboxylic acid extracted from apples and various other fruits.

Hygroscopic
Able to absorb moisture from air.
I
Iodine is in the halogen group of elements.
Ice
Formed when water is cooled below its freezing point.

Immiscible
Incapable of being mixed.
In
Indium is a soft, malleable and ductile metal which is generally unaffected by air or water but is soluble in acids.
Inclusion
Foreign particle present as an undesirable impurity in a material.
Inconel
A nickel based alloy with good corrosion resistance.

Indicator
A substance that undergoes a sharp, easily observable change when conditions in its solutions change.
Indicator Diagram
A plot of pressure vs. volume.
Indirect Titration
Determining the concentration of an analyte by reacting it with a known number of moles of excess reagent.
Indium
A soft, malleable and ductile metal which is generally unaffected by air or water but is soluble in acids.
Inert Gas
A gas which does not normally combine chemically with other elements.
Inflammable Air
An old name for Hydrogen.
Initiator
A compound required to start a chain reaction.
Intensive Properties
Properties which are independent of the amount of the substance.
Intermediate Species
Species formed in a reaction consisting of more than one step.
Intermetallic
A compound of two metals that has a distinct chemical formula. The bonds in intermetallic compounds are often partly ionic.
Intermolecular Forces
Forces between molecules.
Internal Energy
A property of a system that can be changed by a flow of work, heat or both.
Interstitial Site
Octahedral and tetrahedral open spaces within a close-packed arrangement of atoms or ions in which a cation can fit.
Intramolecular Forces
Forces within molecules. Forces caused by the attraction and repulsion of charged particles.
Invar
An alloy of iron and nickel.

Iodine
In the halogen group of elements.
Iodine Number
The number of grams of iodine required to saturate 100 grams of fat.
Ion
An atom, or group of atoms, which has either gained or lost electrons.
Ion Dipole Forces
Intermolecular force that exist between charged particles and partially charged molecules.
Ionic Bond
This describes the electrostatic attraction of two oppositely charged ions in a crystalline lattice.
Ionization Energy
Energy required to remove an electron from a specific atom.
Ionizing Radiation
A particle or a photon with enough energy to knock off an electron from an atom.
Ir
Iridium is a rare, precious metallic element which is hard, brittle and has a low ductility.
Iridium
A rare, precious metallic element which is hard, brittle and has a low ductility.
Iridosmine
Iridosmine (osmiridium) is a naturally occurring alloy of osmium and iridium.
Iron
One of the most abundant metallic elements (41000 ppm) and probably one of the most important, being used on the largest scale of any metal.
Iron Hydroxide

FeO(OH)

Found as the minerals Siderogel and Feroxyhyte. It also has a variant known as Lepidocrocite.

Iron II Chloride

FeCl2

Pale yellow to white crystalline solid.

Iron II Hydroxide

Fe(OH)2

Green colour.

Iron II Oxide

FeO

Black colour powder. The powder in particular can cause explosions as it readily ignites.

Iron II Sulphate

FeSO4

Also known as the mineral Melanterite or Copperas. Green Vitriol is hydrated Iron II Sulphate.

Iron II Sulphide

FeS2

A brassy yellow colour. Also known as pyrite, iron pyrites and fools gold.

Iron III Chloride

FeCl3

Brown black or green crystalline solid.

Iron III Oxide

Fe2O3

Known in its natural state as Haematite, but also purified for use as a coating in magnetic audio and computer media, where it is known as Ferric oxide.

Iron Pyrites
Old name for Iron II Sulphide.
Iron Sulphide

FeS

White crystalline solid.

Isomer
Molecules with identical molecular formulas but different structural formulas.
Isomerization
A chemical change that involves a rearrangement of atoms and bonds within a molecule, without changing the molecular formula.
Isosteric
Having identical valence electron configurations.
Isotactic
A type of polymer chain configuration wherein all side groups are positioned on the same side of the chain molecule.
Isotone
One of a group of atoms or ions with nuclei that contain the same number of neutrons but different numbers of protons.
Isotonic
Refers to solutions that have equal osmotic pressure.
Isotopes
Two atoms having the same number of protons but different numbers of neutrons are said to be isotopes of each other.
Isotopic Abundance
The fraction of atoms of a given isotope in a sample of an element.
Isotopic Mass
The mass of a single atom of a given isotope, usually given in daltons.
Isotropic
Having identical values of a property in all crystallographic directions
K
Potassium is a soft, silvery coloured metal, which like other members of the alkali group of metals, is extremely reactive.
K2O
Chemical formula for Potassium Oxide.
K2O2
Chemical formula for Potassium Peroxide.
K2S
Chemical formula for Potassium Sulphide.
Kalium
The old name for Potassium and from where the chemical symbol K was derived.
Kapok
Used as an insulating or flotation material it comes from the seed hairs of the kapok tree (Ceiba Pentranda).
KBr
Chemical formula for Potassium Bromide.
KCl
Chemical formula for Potassium Chloride.
Keir Metal
Brass containing 55% copper, 40% zinc and 5% iron. Patented in 1779 by James Keir (Chemist, Geologist, Industrialist and Inventor) and used for the manufacture of window frames.

Ketone
Compunds containing a carbonyl group (-CO-) attached to two hydrocarbon radicals. The simplest ketone is acetone (CH3COCH3).
KF
Chemical formula for Potassium Fluoride.
KI
Chemical formula for Potassium Iodide.
Kiln
A furnace in which ceramics are fired.
Kinetics
The study of how fast reactions occur.
kJ
An abbreviation of kilojoule, one thousand joules. The SI unit of energy is the joule.
KMnO4
Potassium Manganate VII
KNO3
Chemical formula for Potassium Nitrate.
KO2
Chemical formula for Potassium Superoxide.
KOH
Potassium Hydroxide.
Kr
Krypton is a rare gaseous element.
Krypton
A rare gaseous element.
La
Lanthanum is a soft, ductile, white metallic element which oxidises rapidly in air.
Lacquer
A fast-drying usually clear coating that is highly flammable and dries by solvent evaporation only.
Lanthanum
A soft, ductile, white metallic element which oxidises rapidly in air.
Lard Oil
An oil made from animal fats usually mixed with mineral oils to reduce its cost and improve its qualities. Used in engineering as a cutting oil.

Lattice
An orderly arrangement of atoms in a material.
Lattice Parameter
The combination of unit cell edge lengths and interaxial angles that defines the unit cell geometry.
Laughing Gas
Nitrous oxide, an anaesthetic.
Lawrencium
The only known isotope has a half life of 8 seconds.
Lead
A soft, malleable and ductile metallic element that has been known of and used since prehistoric times.
Lead II Carbonate

PbCO3

Decomposes readily into Lead II Oxide and carbon dioxide at 200°C and can be reduced to lead using carbon monoxide.

Lead II Chromate IV

PbCrO4

Used as a pigment due to the strong yellow colour.

Lead II Oxide

PbO

Lead monoxide varies in colour from pale yellow to brown, used in the manufacture of glass, paints, varnishes and glazes.

Lead II Sulphide

PbS

Grey crystalline solid.

Lead IV Oxide

PbO2

Lead dioxide a dark brown powder, strong oxidizing agent.

Lean Burn
A fuel air mixture that contains higher amounts of air than normally used.
Leclanché Cell
A electrolytic cell also known as a dry cell that uses a moist paste rather than a liquid as an electrolyte.
Lepidocrocite
Alternative name for Iron Hydroxide.
Lever Rule
Mathematical expression whereby the relative phase amounts in a two-phase alloy at equilibrium may be computed.
Levorotatory
A chiral molecule which rotates plane-polarized light to the left.
Li
Lithium is a soft, silver metal, and is the first member of the alkali group of metals.
Li2
Chemical formula for Lithium I Oxide.
Li2O2
Chemical formula for Lithium I Peroxide.
Li3N
Chemical formula for Lithium I Nitride.
LiBr
Chemical formula for Lithium I Bromide.
LiCl
Chemical formula for Lithium I Chloride.
LiF
Chemical formula for Lithium I Fluoride.
Ligand
A molecule or ion that binds to a metal cation to form a complex.
Lignite
A type of coal with lowest carbon content (25% to 35%) and a low heat value called "brown coal", used mainly for electric power generation.

LiH
Chemical formula for Lithium I Hydride.
LiI
Chemical formula for Lithium I Iodide.
Limestone
Naturally occuring Calcium Carbonate.
Limiting Reagent
The reactant that will be exhausted first.
Linseed Oil
Obtained from the seeds flax. Originally used in the production of paints.
LiO2
Chemical formula for Lithium Superoxide.
Lipid
A diverse group of organic molecules that contain long hydrocarbon chains or rings and are hydrophobic.
Lipowitz Alloy
A low melting point alloy used to form shields in radiotherapy.

Liquefied Natural Gas
Natural gas that has been refrigerated to cryonic temperatures where the gas condenses into a liquid.
Liquid
Matter with a definite volume that takes the shape of its container.
Litharge
Lead monoxide varies in colour from pale yellow to brown, used in the manufacture of glass, paints, varnishes and glazes.
Lithium
A soft, silver metal, and is the first member of the alkali group of metals.
Lithium I Bromide

LiBr

White crystalline solid.

Lithium I Chloride

LiCl

White crystalline solid.

Lithium I Fluoride

LiF

White crystalline solid.

Lithium I Hydride

LiH

White to grey crystalline solid.

Lithium I Iodide

LiI

White crystalline solid.

Lithium I Nitride

Li3N

Purple or red crystalline solid.

Lithium I Oxide

Li2O

White crystalline solid.

Lithium I Peroxide

Li2O2

White crystalline solid.

Lithium Superoxide

LiO2

Yellow crystalline solid.

Litmus
A mixture of pigments extracted from certain lichens that turns blue in basic solution and red in acidic solution.
Litmus Paper
Paper impregnated with litmus, usually cut in narrow strips.
LNG
Abbreviation of Liquefied Natural Gas.
Lock and Key Model
A model that explains the role of enzymes in chemical reactions by assuming that the reactants fit into the enzyme like a key fits into a lock.
London Force
An intermolecular attractive force that arises from a cooperative oscillation of electron clouds on a collection of molecules at close range.
Lone Pair
Electrons that are not involved in bonding.
lox
Liquid oxygen.
Lr
The only known isotope of lawrencium has a half life of 8 seconds.
Lu
Lutetium is the hardest, densest and one of the rarest of the lanthanide group of elements.
Lucite
Tradename for Polymethyl Methacrylate Resin.
Lunar Crystals
Old name for Silver Nitrate.
Lutetium
The hardest, densest and one of the rarest of the lanthanide group of elements.
Lye
Alternative name for Sodium Hydroxide.
Macromolecule
A huge molecule made up of thousands of atoms
Macroscopic
Anything big enough to be seen with the naked eye.
Madelung Constant
A constant representing the sum of the mutual potential coulombic attractive energy of all the ions in a lattice in the equation for the energy of an ionic crystal.
Magnalium
An alloy of magnesium and aluminium used in aircraft manufacture.

Magnesium
A brilliant white metal, which is relatively soft and is one of the more abundant elements in the earth’s crust.
Magnesium Fluoride
Used as antireflection coating for lenses because of its low refractive index.

Magnesium Oxide
Formed by igniting Magnesium in air.
Malic Acid
Another name for Hydroxybutanedioic Acid.
Manganese
A hard, brittle, silvery coloured, metallic element which resembles iron in being moderately reactive and dissolving in cold, dilute non-oxidising acids.
Manganese Bronze
A copper alloy containing zinc, manganese and a small quantity of nickel.

Manganese IV Oxide

MnO2

This blackish or brown solid occurs naturally as the mineral pyrolusite.

Manganin
Alloy with 84% copper, 12% manganese and 4% nickel used in wire form for making heating elements.

Marble
A granular metamorphosed limestone that is often polished and used for decoration.
Marsh Gas
The natural occurence of methane.
Martensite
Martensite is a microconstituent or structure in quenched steel characterized by an acicular or needle-lie pattern on the surface of polish.
Mass Action Law
The law which describes the relation between the densities of species involved in a chemical reaction.
Mass Spectrometer
An instrument for producing ions in a gas and determining their mass and hence composition.
Mass Spectrum
A plot showing the results of a mass spectrometry experiment, which shows the presence of particles with different masses as a series of sharp, separate peaks.
Massicot
Mineral form of Lead II Oxide.
Material Safety Data Sheet
Safety information sheet for a particular substance that lists physical properties, hazards, cleanup and disposal procedures, fire and explosion data, and protective equipment required.
Md
Mendelevium is a man-made element with an atomic number of 101.
Measurement
The collection of quantitative data.
Melanterite
The mineral name for Iron II Sulphate.
Melting Point
The temperature at which a solid substance changes to a liquid state.
Mendelevium
Man-made element with an atomic number of 101.
Mer
The group of atoms that constitutes a polymer chain repeat unit.
Mercuric Chloride
Another name for Mercury II Chloride.
Mercuric Oxide
Another name for Mercury II Oxide.
Mercuric Sulphide

HgS

The ore of mercury. Occuring as red crystals.

Mercurous Chloride
Another name for Mercury I Chloride.
Mercury Dichlorate
Another name for Mercury II Chloride.
Mercury Hg
The most common liquid metal at room temperature.
Mercury I Chloride

Hg2Cl2

Dense white or yellowish-white odorless solid. It was used in medicine as a diuretic and laxative although this is now discontinued.

Mercury II Chloride

HgCl2

One of the most toxic forms of Mercury.

Mercury II Oxide

HgO

A red or orange solid at room temperature that is used in the production of Mercury as it decomposes readily.

Metabolite
A compound produced by metabolic reactions.
Metal
A metal is a substance that conducts heat and electricity, is shiny and reflects many colors of light, and can be hammered into sheets or drawn into wire.
Metallic Compound
Compound that contains at least one metallic element.
Metallic Radius
The atomic radius from as established by measuring the distances between atoms in metallic crystals.
Metallurgy
The science and technology of metals and alloys.
Methanal
Alternative name for Formaldehyde.
Methane
The first alkane. Occurs naturally as marsh gas and in oil wells.
Methane Trichloride
Alternative name for Chloroform.
Methanoic Acid

CH2O2

Most famous for it's occurrence in Ant and Bee venom.

Methanol
A colourless liquid also known as methyl alcohol.
Methenyl Trichloride
Alternative name for Chloroform.
Methyl
The monovalent radical -CH3
Methyl Acetate

C3H6O2

A clear, flammable liquid with a characteristic, not unpleasant smell like certain glues or nail polish removers.

Methyl Alcohol
Also known as methanol.
Methyl Bromide
Alternative name for Bromomethane.
Methyl Chloride
Alternative name for Chloromethane.
Methyl Cyanide
Also known as Acetonitrile.
Methyl Ethanoate
Alternative name for Methyl Acetate.
Methyl Phenyl Ether
Also known as Anisole.
Methyl Trichloride
Alternative name for Chloroform.
Methylbenzene
Also known as toluene.
Methylene Chloride
Alternative name for Dichloromethane.
Methylene Dichloride
Alternative name for Dichloromethane.
Mg
A brilliant white metal, which is relatively soft and is one of the more abundant elements in the earth’s crust.
Mica
A group of silicates with similar chemical composition. Used as an electrical insulator.
Microscopic
Refers to objects that are too small for the unaided eye to see.
Microstructure
The structural features of an alloy that are subject to observation under a microscope.
Mild Steel
A term used for low-carbon machine steel.

Milk
Opaque white liquid secreted by female mammals for feeding young.
Miller Indices
A set of three integers that designate crystallographic planes, as determined from reciprocals of fractional axial intercepts.
Miller-Bravis Indices
A set of four integers that designate crystallographic planes in hexagonal crystals.
Mineral Wool
Also known as rock wool.
Mischmetal
An alloy of cerium, rare-earth metals and iron.

Miscible
Two liquids are considered "miscible" or mixable if shaking them together results in a single liquid phase, with no meniscus visible between layers of liquid.
Mixed Dislocation
A dislocation that has both edge and screw components.
Mixture
Two or more substances which are not chemically bonded together.
Mn
Manganese is a hard, brittle, silvery coloured, metallic element which resembles iron in being moderately reactive and dissolving in cold, dilute non-oxidising acids.
Mo
Molybdenum is a lustrous, silvery coloured metal that resembles tungsten with which it tends to be paired in the transition series in the periodic table.
mol
Abbreviation of Mole, the SI unit of Amount of Substance.
Molality
Concentration measured as moles of solute per kilogram of solvent.
Molar Gas Constant
R = 8.31441 JK-1mol-1
Molar Heat Capacity
The amount of heat required to raise the temperature of 1mol of a substance through 1K.
Molar Heat of Combustion
The amount of energy released in burning completely one mole of substance.
Molar Volume
The volume occupied by one mole of a substance under specified conditions.
Molarity
Concentration of a solution measured as the number of moles of solute per litre of solution.
Mole
The SI unit of the Amount of Substance. It is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12.
Mole Fraction
The number of moles of a particular substance expressed as a fraction of the total number of moles.
Molecular Equation
A molecular equation is a balanced chemical equation in which ionic compounds are written as neutral formulas rather than as ions.
Molecular Formula
Shows the number of atoms of each element present in a molecule.
Molecular Geometry
Shape of a molecule, based on the relative positions of the atoms.
Molecular Sieve
A material that contains many small cavities interconnected with pores of precisely uniform size.
Molecular Weight
The combined weight (as given on the periodic table) of all the elements in a compound.
Molecule
The smallest part of an element or of a covalently bonded compound that can exist independently and still retain the ordinary chemical properties of that element or compound.
Molybdenum
A lustrous, silvery coloured metal that resembles tungsten with which it tends to be paired in the transition series in the periodic table.
Monatomic Ion
An ion formed from a single atom by the loss or gain of electrons.
Monobromomethane
Alternative name for Bromomethane.
Monochloroethane
Alternative name for Chloroethane.
Monomer
A molecule that, under the correct conditions, can link together with others to form larger molecules called polymers.
Montroydite
Another name for Mercury II Oxide.
Mossbauer Spectrometer
An instrument that provides information on the bonding of an atom in a mineral by bombarding it with gamma rays.
Mumetal
An alloy of high magnetic permeability containing up to 78% nickel with iron, copper and manganese.
Muntz Metal
Stonger than normal brass and used for castings and hot worked items. 60 % Copper 40 % Zinc

Mustard Gas
Common name for Dichlorodiethyl Sulphide a gas used in warfare.
N
A gaseous colourless and odourless element that makes up about 80% of the atmosphere.
N2O
Chemical formula for Nitrous Oxide.
Na
Sodium is a soft, silvery coloured metal which, like other members of the alkali group of metals, is extremely reactive.
Na2O
Chemical formula for Sodium Oxide.
Na2O2
Chemical formula for Sodium Peroxide.
NaBr
Chemical formula for Sodium I Bromide.
NaF
Chemical formula for Sodium I Fluoride.
NaH
Chemical formula for Sodium Hydride.
NaI
Chemical formula for Sodium I Iodide.
NaNO3
Chemical formula for Sodium Nitrate.
Nanometre
Abbreviated as nm, unit of length equal to 10-9 metres, and equal to 10 Å (Angstroms).
NaO2
Chemical formula for Sodium I Oxide.
NaOCl
Chemical formula for Sodium Hypochlorite.
NaOH
Chemical formula for Sodium Hydroxide.
Naphtha
Volatile solvent distilled from petroleum.
Naphthyleneethylene
Another name for Acenaphthene.
Natrium
Latin for sodium, hence the symbol Na.
Natural Gas
The cleanest fossil fuel, and hence a potential short-term aid to slowing climate change.

Nb
Niobium is a metallic element that is very reactive and forms an extremely stable oxide when exposed to air which enhances its corrosion resistance.
Nd
Neodymium is one of the more reactive members of the lanthanide group.
Ne
Neon is a light gaseous inert element.
Neodymium
One of the more reactive members of the lanthanide group.
Neon
Light gaseous inert element.
Neptunium
Produced artificially by nuclear reaction between uranium and neutrons.
Network Polymer
A polymer composed of trifunctional mer units that form three-dimensional molecules.
Neutral Ammonium Fluoride
Alternative name for Ammonium Fluoride.
Neutral Solution
An aqueous solution in which the concentrations of aqueous hydrogen ions and hydroxide ions are equal.
Newtonian Fluid
A fluid whose viscosity does not depend on gradients in flow speed.
Newtons Alloy
A low melting point alloy.

NH2CH2COOH
Chemical formula for Glycine.
NH2CONH2
Chemical formula for Carboxamide or more commonly known as Urea.
NH3
Chemical formula for Ammonia.
NH4Cl
Chemical formula for Ammonium Chloride.
NH4F
Chemical formula for Ammonium Fluoride.
NH4I
Chemical formula for Ammonium Iodide.
NH4NH4CO3
Chemical formula for Ammonium Carbonate.
NH4NO3
Chemical formula for Ammonium Nitrate.
NH4OH
Chemical formula for Ammonium Hydroxide.
Ni
Nickel is a metallic element that is malleable and ductile, and is resistant to corrosion in air or water, and hence is used as a protective coating.
Niacin
Vitamin B3 is a crystalline acid found in meat and yeast and produced by the oxidation of nicotine.
Nichrome
An alloy of nickel and chromium used for heating elements.

Nickel
A metallic element that is malleable and ductile, and is resistant to corrosion in air or water, and hence is used as a protective coating.
Nickel Brass
A copper alloy containing zinc and a small quantity of nickel.

Nicotine

CH14N2

Colourless, very poisonous oily liquid.

Nicotinic Acid
Vitamin B3 is a crystalline acid found in meat and yeast and produced by the oxidation of nicotine.
Nimonic
An alloy consisting of roughly 80% nickel and 20% chromium with additives such as titanium and aluminium.
Niobium
As a pure metallic element it is very reactive and forms an extremely stable oxide when exposed to air which enhances its corrosion resistance.
Nitrate
The NO3- ion, formed by reaction of nitric acid with a base or a compound containing the NO3- ion.
Nitre
Old fashioned name for Potassium Nitrate.
Nitric Acid

HNO3

Colourless, corrosive, acid liquid that attacks most metals and other substances releasing nitrogen dioxide.

Nitric Oxide
A colourless gas that forms nitrogen dioxide in contact with air.
Nitrile
An organic compound which has a -C=N functional group.
Nitrite
The NO2- ion, formed by reaction of nitrous acid with a base or a compound containing the NO2- ion.
Nitrobenzene
A yellow liquid obtained from the action of concentrated nitric and sulphuric acid on benzene.
Nitrogen
A gaseous colourless and odourless element that makes up about 80% of the atmosphere.
Nitrogen Oxides
Several air-polluting gases composed of nitrogen and oxygen which play an important role in the formation of photochemical smog.
Nitroglycerine

C3H5N3O9

A heavy, yellow or colourless, oily, explosive liquid obtained by nitrating glycerol.

Nitrous Oxide
Also known as laughing gas, an anaesthetic.
No
Nobelium is a man-made element with an atomic number of 102.
Nobel Prize
Awarded annually as per Alfred Nobel′s last will and testament.
Nobelium
A man-made element with an atomic number of 102.
Noble Gases
The gaseous chemical elements helium, neon, argon, krypton, xenon and radon, which are all placed in Group 0 of the Periodic Table.
Noble Metals
Metals, such as gold, silver and platinum, that show a marked reluctance to combine with other elements to form compounds.
Nonane

C9H20

A colourless volatile liquid, an ingredient of ordinary kerosene.

Noncrystalline
The solid state wherein there is no long-range atomic order. Sometimes used synonymously with the terms amorphous, glassy and vitreous.
Nonelectrolyte
A substance which does not ionize in solution.
Non-Metal
A term usually reserved for those chemical elements that are very poor electrical conductors in the solid state and liquid states.
Non-Newtonian Fluid
A fluid whose viscosity changes when the gradient in flow speed changes.
Nonpolar Molecule
A molecule in which the center of positive charge and the center of negative charge coincide.
Nordic Gold
A 89% copper, 5% aluminium, 5% zinc and 1% tin alloy.

NOx
Abbreviation of Nitrogen Oxides where x represents a varying proportion of oxygen.
Np
Neptunium is produced artificially by nuclear reaction between uranium and neutrons.
Nuclear Binding Energy
Energy needed to break an atomic nucleus into separate protons and neutrons.
Nuclear Energy
Energy stored in the nucleas of an atom.
Nucleation
The initial stage in a phase transformation.
Nucleic Acid
A polymer made of repeating nucleotides. Examples are DNA and RNA.
Nylon
A synthetic polymer used in the manufacture of fibres.
O
Oxygen is a colourless and odourless element that is essential for most life forms on earth. It is also the most abundant element on earth.
O3
Allotropic form of oxygen containing three atoms in the molecule.
Octahedral Position
The void space among closed-packed, hard sphere atoms or ions for which there are six nearest neighbours.
Octal
A number system using the base-8, i.e., each digit can be any of 8 values, represented by the digits 0-7.
Octane
Flammable liquid compounds found in petroleum and natural gas.
Octane Number
A rating of the 'knock' characteristics of motor fuels.
Octet
A set of eight valence electrons.
Octet Rule
A guideline for building Lewis structures that states that atoms tend to gain, lose, or share valence electrons with other atoms in a molecule until they hold or share eight valence electrons.
Oil
An oil is any substance that is in a viscous liquid state at ambient temperatures or slightly warmer, and is both hydrophobic and lipophilic.
Oil of Bitter Almond
Old name for Benzaldehyde.
Oil of Mirbane
Old name for Nitrobenzene.
Oil of Vitriol
Alternative name for Sulphuric Acid.
Oleoresin
A natural plant product that contains oil and resins, an example is turpentine.
Olive Oil
Obtained from the fruit of Olea Europaea.
Orbital
A wavefunction that describes what an electron with a given energy is doing inside an atom or molecule.
Ore
A natural mineral mined and treated for extraction of its components.
Organic Chemistry
The branch of chemistry that deals with the properties and reactions of carbon-based compounds.
Organic Compound
Compounds that contain carbon chemically bound to hydrogen.
Organochromic Indicators
Coloured organic compounds that change colour when they chelate different metals.
Orichalchum
A Roman brass that consisted of 80% copper and 20% zinc.

Ormolu
An alloy of copper, zinc and tin in various proportions with at least 50% copper.

Orthophospheric Acid
Another name for Phosphoric Acid.
Os
Osmium is a member of the platinum group of metals and is commonly found in conjunction with these elements.
Osmiridium
Osmiridium (iridosmine) is a naturally occurring alloy of osmium and iridium. Used to make long-wearing tips for gold fountain-pen nibs.
Osmium
A member of the platinum group of metals and is commonly found in conjunction with these elements.
Osmometry
Determination of the average molecular weight of a dissolved substance from measurements of osmotic pressure.
Osmosis
Passage of solvent molecules from a dilute solution through a semipermeable membrane to a more concentrated solution.
Osmotic Pressure
Pressure which must be applied to a solution to prevent water from flowing in via a semipermeable membrane.
Oxalic Acid

H2C2O4

A relatively strong organic acid, being about 10,000 times stronger than acetic acid.

Oxidation
The loss of one or more electrons by an atom, molecule, or ion.
Oxidation Half Reaction
That part of a redox reaction that involves loss of electrons.
Oxidation Number
A number assigned to each atom to help keep track of the electrons during a redox-reaction.
Oxidation Reaction
A reaction where a substance loses electrons.
Oxide
A binary compound that contains oxygen in the -2 oxidation state.
Oxidizing Agent
Cause other substances to be oxidized in chemical reactions while they themselves are reduced.
Oxyacid
When one or more hydroxide (OH) groups are bonded to a central atom.
Oxygen
A colourless and odourless element that is essential for most life forms on earth. It is also the most abundant element on earth.
Ozone

O3

Allotropic form of oxygen containing three atoms in the molecule.

P
Phosphorus is a non-metallic element.
Pa
Protactinium is a radioactive element.
Palladium
A member of the platinum group of metals. It is silvery white in colour, is malleable and ductile, and is one of the most reactive in the group
Paracetamol
Another name for Acetaminophen.
Paraffin Oil
A term describing a whole series of saturated aliphatic hydrocarbons, also known as alkane hydrocarbons.
Paraffin Wax
Obtained as a residue from the distillation of petroleum.
Parent Isotope
An element that undergoes nuclear decay.
Partial Miscibility
Two liquids are considered partially miscible if shaking equal volumes of the liquids together results in a meniscus visible between two layers of liquid, but the volumes of the layers are not identical to the volumes of the liquids originally added.
Partial Pressures
The pressure exerted by a certain gas in a mixture.
Particulate
Composed of distinct particles.
Parts Per Million
Used to describe the amount of a trace element or substance present in the main substance.
Patina
A thin layer of corrosion products with a distinctive colouration that forms on a metal surface exposed to air and water.
Pb
Lead is a soft, malleable and ductile metallic element that has been known of and used since prehistoric times.
PbCO3
Lead II Carbonate, decomposes readily into Lead II Oxide and carbon dioxide at 200°C and can be reduced to lead using carbon monoxide.
PbCrO4
Lead II Chromate IV, used as a pigment due to strong yellow colour.
PbO
Lead monoxide varies in colour from pale yellow to brown, used in the manufacture of glass, paints, varnishes and glazes.
PbO2
Lead dioxide a dark brown powder, strong oxidizing agent.
Pd
Palladium is a member of the platinum group of metals. It is silvery white in colour, is malleable and ductile, and is one of the most reactive in the group
Pearl Ash
An old fashioned name for Potassium Carbonate.
Pearlite
A lamellar aggregate of ferrite and cementite.
Peat
Partially carbonized vegetable material, usually found in bogs.

Pentane

C5H12

The fifth member of the paraffin series. Pentane exists in three isomeric forms.

Pentanol

C5H11OH

A colourless liquid at room temperature with a choking aroma.

Peptide
A short polymer made by linking together amino acid molecules.
Percent Yield
Equals experimental yield divided by theoretical yield times 100%.
Perfluoromethane
Alternative name for Tetrafluoromethane.
peri-Ethylenenaphthalene
Another name for Acenaphthene.
Periodic Law
The properties of the elements are periodic functions of their atomic numbers.
Periodic Table
The most commonly used arrangement of the periodic system.
Peritectic
An isothermal reversible reaction in metals where a liquid phase reacts with a solid phase to produce a single, different, solid phase upon cooling.
Permangante of Potash
Old fashioned name for Potassium Manganate VII.
Permeability
  1. passage or diffusion of a gas, vapor, liquid, or solid through a material without physically or chemically affecting it.
  2. Term used to express various relationships between magnetic induction and magnetizing force; either absolute permeability or specific (relative) permeability.
Perspex
Tradename for Polymethyl Methacrylate Resin.
Pesticide
A chemical or biological agent that kills pests.
Petrol
A volatile, flammable liquid mixture of hydrocarbons, obtained from petroleum and used as a fuel for internal-combustion engines.

Petroleum
An oily, thick, flammable, usually dark coloured liquid that is a form of bitumen or a mixture of various hydrocarbons, occurring naturally in various parts of the world and often separated by distillation into petrol, naphtha, benzene, kerosene and paraffin.

pH
Measures the acidity of a solution. It is the negative logarithm of the concentration of the hydrogen ions in a substance.
Pharmacognosy
Identification, isolation, and characterization of biologically active substances in living things.
Pharmacology
The study of drugs, which includes determination of biological activity, biological effects, breakdown and synthesis, and delivery.
Phase Boundary
A surface where two samples of matter with different properties are in contact.
Phase Change
The change from gas to liquid to solid.
Phenol
Also known as carbolic acid. It is used as a strong disinfectant.
Phenolic Resin
A condensation reaction polymer. A key characteristic of phenolic resin is the ability to withstand high temperature, along with mechanical load with minimal deformation or creep. In other words, cured phenolic resin provides the product rigidity necessary to maintain structural integrity and dimensional stability even under severe conditions.

Phenyl Methyl Ketone
Alternative name for Acetophenone.
Phenylamine
Alternative name for Aniline.
Philosopher′s Wool
An old name for Zinc Oxide.
Phlogisticated Air
An old name for Nitrogen.
Phlogiston
A hypothetical elastic fluid which was seen as a metalizing and combustible principle.
Phosphor Bronze
An alloy of copper with 3.5 to 10% of tin and a significant phosphorus content of up to 1%.

Phosphorescence
The property of a material whereby it continues to emit visible light after it has been illuminated by ultraviolet light.
Phosphoric Acid

H3PO4

An inorganic acid.

Phosphorus
A non-metallic element.
Photo Etching
Chemical process of removing unwanted material in producing printed circuit boards.
Photochemistry
The study of the effects of light on chemical reactions.
Pi Bonds
A type of covalent bond in which the electron density is concentrated around the line bonding the atoms.
Piano Wire
High quality steel wire used for making springs.

Piezoelectric
Any material which provides a conversion between mechanical and electrical energy.
Pinchbeck
A cheap bronze alloy.
Pitchblende
The most important Uranium ore.
Plane Wood
A North American wood that resembles beech, durable in water but not in air.

Plastic
A solid material in the primary ingredient of which is an organic polymer of high molecular weight.
Plasticizer
A low molecular weight polymer additive that enhances flexibility and workability and reduces stiffness and brittleness.
Platinum
A lustrous, malleable and ductile metallic element.
Plumbago
The natural allotropic form of carbon.
Plumbum
Latin for lead, hence the symbol Pb.
Plutonium
A product of the radioactive decay of neptunium.
Pm
Promethium is a radioactive element of the rare earth series.
Po
Polonium is a radioactive element.
pOH
Measures the basicity of a solution. It is the negative logarithm of the concentration of the hydroxide ions.
Point Defect
A crystalline defect associated with one or, at most, several atomic sites.
Polar Bond
A bond involving electrons that are unequally shared.
Polar Molecules
Molecule with a partial charge.
Polarization
For an atom, the displacement of the centre of the negatively charged electron cloud relative to the positive nucleus, which is induced by an electric field.
Polonium
A radioactive element.
Polyatomic Ion
An ion formed by the loss or gain of electrons from a molecule or chemical group composed of two or more atoms.
Polyatomic Molecule
An uncharged particle that contains more than two atoms.
Polycrystalline
Referring to crystalline materials that are composed of more than one crystal or grain.
Polyethylene
Plastic used heavily in the packaging industry.

Polymer
A large molecule formed by the linking together of many smaller molecules known as monomers.
Polymerization
The process by which monomers are joined together to give a polymer.
Polymerize
To link smaller molecules together to form a larger molecule.
Polymethyl Methacrylate Resin
Commonly known as perspex or lucite, a transparent plastic.

Polystyrene
Expanded polystyrene was the first foamed polymer. It is the white rigid plastic used for thermal insulation and in flotation devices.

Polytetrafluoroethylene
Commonly known as Teflon, a thermoplastic polymer used for non-stick coatings and bearings.

Polythene
Alternative name for Polyethylene.
Polyvinyl Acetate
A colorless, thermoplastic, water soluble, resinous high polymer derived from the polymerization of vinyl acetate with a catalyst. Abbreviated as PVA.

Polyvinyl Chloride
Plastic used in many different forms. Commonly abbreviated as PVC.

Ponderous Spar
Old name for Barium Sulphate.
Potash
Old fashioned name for Potassium Carbonate made from the ashes of burnt wood.
Potassium
A soft, silvery coloured metal, which like other members of the alkali group of metals, is extremely reactive.
Potassium Bromide

KBr

A white crystalline salt used in photography. It was used in medicine as a sedative.

Potassium Carbonate

K2CO3

A white very soluble deliquescent salt.

Potassium Chloride

KCl

White crystalline solid.

Potassium Fluoride

KF

White crystalline solid.

Potassium Hydroxide

KOH

A white deliquescent solid that dissolves in water to give an alkaline solution.

Potassium Iodide

KI

White crystalline solid.

Potassium Manganate VII

KMnO4

Deep purple, crystalline, soluble salt. Dissolves in water to produce a strong oxidizing agent. Used as a disinfectant.

Potassium Nitrate

KNO3

The salt of potassium and nitric acid. Used in pyrotechnics, explosives, the manufacture of glass and as a fertilizer.

Potassium Oxide

K2O

Yellowish white yo grey crystalline solid.

Potassium Permanganate
Deep purple, crystalline, soluble salt.
Potassium Peroxide

K2O2

Yellow or orange solid.

Potassium Sulphide

K2S

White, yellow, red or brown.

Potassium Superoxide

KO2

Yellow crystalline solid.

Potin
An ancient alloy of copper, zinc, lead and tin that was used to make coins.

Power Density
Characteristic parameter of a battery/electrical power source indicating its electrical power per unit weight or volume.
ppm
Abbreviation for Parts Per Million.
Pr
Praseodymium is a soft, white metal and a member of the lanthanide group of elements.
Praseodymium
A soft, white metal and a member of the lanthanide group of elements.
Precipitate
A solid that appears in the form of fine particles in what was previously a clear solution because of a chemical reaction.
Precipitation Heat Treatment
Artificial aging in which a constituent precipitates from a supersaturated solid solution.
Prepreg
A continuous fibre reinforcement pre-impregnated with a polymer resin which is then partially cured.
Primary Bond
Interatomic bonds that are relatively strong and for which bonding energies are relatively large.
Promethium
A radioactive element of the rare earth series.
Propane

C3H8

A member of the alkane series, a colourless, odourless gas at room temperature. In liquid form it is often referred to as Liquid Petroleum Gas (LPG).

Propanol

CH3CH2CH2OH

Used as an inexpensive alcohol. Also known as propyl alcohol.

Propanone
Alternative name for Acetone.
Propene

C3H6

A colourless highly flammable gas.

Propene Acid
Alternative name for Acrylic Acid.
Propenoic Acid
Alternative name for Acrylic Acid.
Propyl Alcohol
Alternative name for Propanol.
Propylene
Alternative name for Propene.
Protactinium
A radioactive element.
Protein
A very large, naturally occurring polyamide formed from a selection of the 20 or so naturally occurring amino acids.
Protium
The lightest element of hydrogen of unit mass and the most prevalent in the universe.

Prussic Acid
A solution of Hydrogen Cyanide in water.
Pt
Platinum is a lustrous, malleable and ductile metallic element.
PTFE
Abbreviation of Polytetrafluoroethylene, a thermoplastic polymer used for non-stick coatings and bearings.
Pu
Plutonium is a product of the radioactive decay of neptunium.
Pumice
A light porous stone of mixed silicates.

Pure Air
An old name for oxygen
Pure Substance</