2011+Important+Definitions

=Important Definitions=

These are a small number of definitions that may pop up here and there. Please feel free to add any more that you think may be appropriate. Don't worry too much about the formatting. :)

BoS Key Terms
A list of the Board of Study Key terms has been compiled [|Here]. Quizlet is a powerful tool for rote-learning such terms and definitions. An account is free.

Elements
A chemical element, or an element, is a material which cannot be broken down or changed into another substance using chemical means. Elements may be thought of as the basic chemical building blocks of matter. Depending on how much evidence you require to prove a new element has been created, there are 117 or 118 known elements.

Compounds
A compound is a pure substance that can be broken down into simpler elements through the use of separation. Compounds have a fixed ratio of atoms in each molecule.

Mixtures
A mixture is the combination of elements that are not chemically combined. Mixtures can be categorised as homogeneous and heterogeneous. A homogeneous mixture is a type of mixture in which the composition is uniform. A heterogeneous mixture is a type of mixture in which the components can easily be identified, as there are two or more phases present. Air is a homogeneous mixture of the gaseous substances nitrogen, oxygen, and smaller amounts of other substances. Salt, sugar, and many other substances dissolve in water to form homogeneous mixtures. A homogeneous mixture in which there is both a solvent and solute present is also a solution.

Isotopes
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation of the atom as a particular element. Different isotopes of hydrogen are Hydrogen-1 Protium, Hydrogen-2 Deuterium, Hydrogen-3 Tritium. These isotopes continue to Hydrogen-7. []

Allotrope
An allotrope is a form that an element takes due to its bonds. The most common example is Carbon. Carbon has two main allotropes that are formed naturally. These are diamond, which is the hardest material known to man and graphite which is sheets of carbon that move around on top of each other. Other allotropes are buckminsterfullerene, lonsdaleite, Amorphous carbon and carbon nanotube.

Isomers
Are like allotropes but are compounds with different structural formulas. Isomers do not necessarily have the same properties as each other and may vary.

=Addition polymerisation=

=Addition reaction=
 * Method where simple monomer units unite together to form a long-chain polymer by simple addition (No other product is formed)

... =Alcohol=

... =Alkanols=

=Alkyl group=
 * An organic compound in which a **hydroxyl** (-OH) group is bound to a carbon atom of an alkyl group
 * They are derived from saturated and unsaturated hydrocarbons by a **hydroxyl** (-OH) group.
 * General formula [[image:http://mathurl.com/7ac3crd.png]]
 * **Alcohol** and **alkanol** can be used interchangably

... =Amide link=

... =Amine Group=

... =Amino Acid=

... =Average Molecular weight=

... =Biomass=

=Biodegradable=
 * The total mass, or weight, of living material in a particular area. (Includes wood, straw, bagasse (pulp of sugar cane after juice has been extracted))

... =Biopolymer=

=Carboxylic Acid Group=
 * Polymers that are made totally, or in large part, by living organisms. Examples include cellulose, starch and proteins but also include partly synthesised polymers such as rayon, cellophane and cellulose nitrate (used in the movie industry, the last example)

... =Cat Cracker=

... =Catalytic Cracking=

=Chain Branching=
 * Cracking using catalysts to sustain or perpetuate the reaction

... =Chain Stiffening=

... =Condensation polymerisation=

=Cracking=
 * A method where monomer units unite together to form a long-chain polymer with the elimination of some small molecule, such as water, between pairs of monomers

... =Cross-Linking=

... =Dehydration=

=Fermentation=
 * Process of removing water

... =Hydration Reaction=

... =Molar Heat Of Combustion=

=Monomer=
 * Amount of heat generated when one mole of a substance is **completely** combusted

=Peptide Link=
 * Small chained chemical unit that must be linked over and over to form a larger chain

... =Polyamide=

... =Polyester=

... =Polymer=

=Polymerisation=
 * A substance composed of very large molecules (macromolecules) built up by repeated links of small molecules (monomers)

... =Steam (or Thermal) Cracking=

... =Substitution Reaction=


 * A reaction in which a functional group in a particular chemical compound is replaced by another group
 * Usually occurs in the alkane homologous series

=Zeolites=

=Ziegler-Natta Process (or catalyst)=
 * Complex aluminosilicates consisting of large lattices of aluminium, silicon and oxygen atoms
 * Used as an industrial catalyst (for catalytic cracking)

... http://mathurl.com/7ac3crd.png