F324 Definitions Flashcards
Adsorption
The process that occurs when a gas, liquid or solute is held to the surface of a solid, more rarely a liquid.
Electronegativity
A measure of the attraction of a bonded atom for the pair of the electrons in a covalent bond.
Intermediate
A species formed in one step and used up in a subsequent step and so never seen as either a reactant or a product.
Nucleophile
An atom (or group of atoms) which donates a pair of electrons to form a new covalent bond.
Electrophile
An atom (or group of atoms) that accepts a pair of electrons to form a new covalent bond.
Addition polymer
A polymer which is formed by an addition reaction, where many monomers bond together via rearrangement of bonds (double => single) without the loss of any atom or molecule.
Condensation polymer
A polymer formed by the joining up of monomers by means of a condensation reaction. Examples: proteins, polyamides, polyesters.
Condensation reaction
A reaction in which two monomers react together to form a larger polymer with the elimination of a small molecule such as water.
E/Z Isomerism
A type of stereoisomerism in which different groups attached to each carbon of a C=C double bond may be arranged differently in space because of the absence of rotation around the C=C bond.
E or Trans - across the double bond
Z or cis - same side of the double bond
Esterification
The reaction of an alcohol with a carboxylic acid to produce an ester and water.
Halogen Carrier
A compound such as AlCl₃ or FeBr₃ that can catalyse the halogenation of arenes. They produce a stronger electrophile by polarising the halogen molecule to produce a Cl+ or Br+ electrophile.
Hydrolysis
A reaction with water that breaks a compound into two smaller compounds. Usually carried out under acidic or basic conditions, with slightly different products.
Isoelectric point
The pH at which an amino acid exists mainly as zwitterion.
The pH at which the overall charge of the amino acid is 0.
Mobile phase
The phase (gas or liquid) that moves in chromatography.
Monomer
A small molecule that combines with many other monomers to form a polymer.
Optical Isomers
Stereoisomers that are non-superimposable mirror images of each other.
Peptide
A compound containing amino acids linked by peptide bonds. Often the number of amino acids is indicated by the prefix, di-, tri-, tetra-.
Pharmacological activity
The beneficial or adverse effects of a drug on living matter.
Phenol
An arene that contains a hydroxyl (-OH) group directly bonded to one of the carbons in the aromatic ring. Phenol is both a compound (C₆H₅OH) and a functional group. Most phenols have antibacterial activity.
Pi Bond
The part of a double bond formed above and below the plane of the bonded atoms by sideways overlapping p-orbitals.
Polymer
A long molecular chain built up from monomer units.
Protein
A polypeptide (amino acid polymer) with more than 40 or so monomers.
Reflux
The continuous boiling and condensing of a reaction mixture to ensure that the reaction takes place without the contents of the flask boiling away.
Repeat Unit
A specific arrangement of atoms that occurs in the structure of a polymer over and over again. Repeat units are included in brackets, outside which is the symbol n.
Retention Time
The time for a component to pass through a chromatographic column up to the detector.
Stationary phase
The phase that does not move in chromatography (normally a solid or a liquid adsorbed onto a solid).
Stereoisomers
Compounds with the same structural formula but with a different arrangement of the atoms in space.
Structural isomers
Molecules with the same molecular formula but with different structural formulae.
Trans-esterification
Reaction in which an alcohol reacts with an ester to form another ester, effectively transferring the carboxylic acid group from one alcohol to another. Used to make biodiesel.
Trans-fat
An unsaturated triglyceride containing one or more trans double bonds.
Triglyceride
A triple ester formed by three fatty acids (relatively long carboxylic acids) bonded to a glycerol molecule. Oils and fats are triglycerides.
Zwitterion
An ionic form of an amino acid that contains both positively and negatively charged groups. As both charges are present there is no overall charge.
Arene
An aromatic hydrocarbon.
Aromatic
Containing a ring with a delocalised π electron system.
Biodiesel
Processed fuel made from the transesterification of vegetable oil + methanol or ethanol. It can be used in unmodified diesel engines.
Chemical Shift
A scale that compares the frequency of an NMR absorption with the frequency of the reference peak of Tetramethylsilane (TMS) at δ = 0 ppm.
Chiral Carbon / Chiral Centre
A carbon atom attached to four different groups.
Chromatogram
A visible record showing the result of separation of the different components of a mixture by chromatography.
Delocalised electrons
Electrons that are shared between more than two atoms.
