Definitions for AS OCR chemistry A

The part of the organic molecule responsible for its chemical reactions.

A series of organic compounds with the same functional group but with each successive member differing by CH2.

An alkane with a hydrogen atom removed. For example, CH3, C2H5 etc.

The simplest algebraic formula of a member of a homologous series. For example, alkanes have the general formula of CnH2n+2, alkenes- CnH2n, alcohols- CnH2n+1OH.

Shows the relative positioning of all the atoms in a molecule and the bonds between them.

The minimal detail for the arrangement of atoms in a molecule.

• Simplified organic formula with hydrogen atoms removed from the alkyl chains
• leaving just the carbon skeleton and functional groups.

Molecules with the same molecular formula but with different structural arrangements of atoms.

Same structural formula but with a different arrangement of atoms in space.

• Different groups are attached to each carbon of a carbon-carbon double bond.
• These may be arranged differently in space because of the restricted rotation of the carbon-carbon double bond.

• A special type of E/Z isomerism.
• There is a hydrogen and a non-hydrogen group on each C of the carbon-carbon double bond.
• The Cis isomer (Z) has hydrogens on the same side.
• The Trans (E) has hydrogens on different sides.

The breaking of a covalent bond with one of the bonded electrons going to each atom to form two radicals.

The breaking of a covalent bond with both of the bonded electrons going to one of the atoms forming a cation and an anion.

An atom that is attracted to an electron deficient atom where it donates a pair of electrons to form a new covalent bond.

A species with an unpaired electron.

An atom that is attracted to an electron rich atom where it accepts a pair of electrons to form a new covalent bond.

A reactant is added across an unsaturated molecule to make a saturated molecule. In other words...

• double bonds to single bonds
• 2 reactants to 1 product

An atom is replaced with a different atom.

• 2 reactants to 2 products

Removal of a molecule from a saturated to make an unsaturated.

• Single bonds to double bonds
• 1 reactant to 2 products

Separation of components in a liquid mixture into fractions which differ in boiling points.

Breaking down a long chained saturated hydrocarbon to form a mixture of short chained alkanes and alkenes.

A radical replaces a different atom.

A sequence of steps showing the path taken by electrons in a reaction.

The FIRST step in radical substiution in which the free radicals are generated by UV radiation.

The LAST step in radical substitution when two radicals combine to form a molecule.

• The reactive part of the double bond.
• It is formed above and below the plane of bonded atoms by overlap of p-orbitals.

An organic ion where the carbon atom has a positive charge.

Shows the movement of an electron pair in the breaking and formation of a covalent bond.

A long molecular chain built up from many small monomer units.

An unsaturated alkene (monomer) adds on to a polymer chain one at a time to form a long saturated molecular chain.

A very long molecular chain formed by repeated addition reactions of many unsaturated alkene molecules (monomers).

• A specific arrangement of atoms that occur in the structure over and over again.
• The repeat units will be in brackets outside of which is the symbol n.