Some Vocabulary – Organic Chemistry

• Achiral –lacking handedness – a molecules is achiral if it is superimposable on its mirror image.

• Addition reaction – the reaction wheretwo reactants combine to form a single new product – typically the addition of a halogen, hydrogen, HCl to a double bond.

• Aromatic – a class of compounds that contain a benzene-like six-membered ring with three apparent double bonds.

• Carbocation – a carbon cation or a carbon which makes three covelent bonds and has only six valence electrons in outer energy level. Has a trigonal planar molecular geometry.

• Chiral – Handed.  A molecule that is not superimposable on its mirror image.

• Cis-trans isomers (geometric isomers) – stereoisomers (same connection of atoms) that differ in their arrangement in

space about a double bond or ring.

• Dehydration reaction – elimination of water from an alcohol to form an alkene.

• Electrophile – an electron-poor molecule or anion that can accept an electron pair from an electron-rich molecule or  cation.

• Enantiomers – stereoisomers (same connection of atoms) whose mirror images are non-superimposable.

• Functional  group – an atom or group of atoms that is part of a larger molecule and has a characteristic chemical  reactivity.

• Mechanism – a complete step-by-step description of how a reaction happens.  The movement of a pair of electrons as the  reaction occurs, is represeted by the complete arrows.

• Nylon – a polymer with many amide linkages prepared by the reaction between a diacid and a diamine.

• Nucleophile – an electron-rich molecule or anion that can donate an electron pair to an electron-poor molecule or cation.

• Nucleophilic substitution reaction – a substitution reaction in which one nucleophile replaces another.

• Optical activity – the ability of a molecule in solution to rotate plane-polarized light.

• Plane-polarized light – ordinary light that its electric vectors in a single plane rather than in random planes.

• Polyester – a polymer with many ester linkages prepared by the reaction between a diacid and a dialcohol.

• Racemic mixture – a 50:50 mixture of two enantiomers of a chiral substances – shows no optical activity.

• Free Radical – a highly reactive neutral atom or molecule which has an odd number of electrons.

• Resonance forms – representations of a molecule that differ only in where the bonding electrons are placed.

• Stereochemistry – the branch of chemistry concerned with the three dimensional arrangement of atoms in molecules.

• Structural isomers –molecules with the same molecular formula but whose atoms are connected by covalent bonds in a different order.