F324 Definitions

Question 1

Adsorption

Answer 1

The process that occurs when a gas, liquid or solute is held to the surface of a solid, more rarely a liquid.

Question 2

Electronegativity

Answer 2

A measure of the attraction of a bonded atom for the pair of the electrons in a covalent bond.

Question 3

Intermediate

Answer 3

A species formed in one step and used up in a subsequent step and so never seen as either a reactant or a product.

Question 4

Nucleophile

Answer 4

An atom (or group of atoms) which donates a pair of electrons to form a new covalent bond.

Question 5

Electrophile

Answer 5

An atom (or group of atoms) that accepts a pair of electrons to form a new covalent bond.

Question 6

Addition polymer

Answer 6

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.

Question 7

Condensation polymer

Answer 7

A polymer formed by the joining up of monomers by means of a condensation reaction. Examples: proteins, polyamides, polyesters.

Question 8

Condensation reaction

Answer 8

A reaction in which two monomers react together to form a larger polymer with the elimination of a small molecule such as water.

Question 9

E/Z Isomerism

Answer 9

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

Question 10

Esterification

Answer 10

The reaction of an alcohol with a carboxylic acid to produce an ester and water.

Question 11

Halogen Carrier

Answer 11

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.

Question 12

Hydrolysis

Answer 12

A reaction with water that breaks a compound into two smaller compounds. Usually carried out under acidic or basic conditions, with slightly different products.

Question 13

Isoelectric point

Answer 13

The pH at which an amino acid exists mainly as zwitterion.

The pH at which the overall charge of the amino acid is 0.

Question 14

Mobile phase

Answer 14

The phase (gas or liquid) that moves in chromatography.

Question 15

Monomer

Answer 15

A small molecule that combines with many other monomers to form a polymer.

Question 16

Optical Isomers

Answer 16

Stereoisomers that are non-superimposable mirror images of each other.

Question 17

Peptide

Answer 17

A compound containing amino acids linked by peptide bonds. Often the number of amino acids is indicated by the prefix, di-, tri-, tetra-.

Question 18

Pharmacological activity

Answer 18

The beneficial or adverse effects of a drug on living matter.

Question 19

Phenol

Answer 19

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.

Question 20

Pi Bond

Answer 20

The part of a double bond formed above and below the plane of the bonded atoms by sideways overlapping p-orbitals.

Question 21

Polymer

Answer 21

A long molecular chain built up from monomer units.

Question 22

Protein

Answer 22

A polypeptide (amino acid polymer) with more than 40 or so monomers.

Question 23

Reflux

Answer 23

The continuous boiling and condensing of a reaction mixture to ensure that the reaction takes place without the contents of the flask boiling away.

Question 24

Repeat Unit

Answer 24

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.

Question 25

Retention Time

Answer 25

The time for a component to pass through a chromatographic column up to the detector.

Question 26

Stationary phase

Answer 26

The phase that does not move in chromatography (normally a solid or a liquid adsorbed onto a solid).

Question 27

Stereoisomers

Answer 27

Compounds with the same structural formula but with a different arrangement of the atoms in space.

Question 28

Structural isomers

Answer 28

Molecules with the same molecular formula but with different structural formulae.

Question 29

Trans-esterification

Answer 29

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.

Question 30

Trans-fat

Answer 30

An unsaturated triglyceride containing one or more trans double bonds.

Question 31

Triglyceride

Answer 31

A triple ester formed by three fatty acids (relatively long carboxylic acids) bonded to a glycerol molecule. Oils and fats are triglycerides.

Question 32

Zwitterion

Answer 32

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.

Question 33

Arene

Answer 33

An aromatic hydrocarbon.

Question 34

Aromatic

Answer 34

Containing a ring with a delocalised π electron system.

Question 35

Biodiesel

Answer 35

Processed fuel made from the transesterification of vegetable oil + methanol or ethanol. It can be used in unmodified diesel engines.

Question 36

Chemical Shift

Answer 36

A scale that compares the frequency of an NMR absorption with the frequency of the reference peak of Tetramethylsilane (TMS) at δ = 0 ppm.

Question 37

Chiral Carbon / Chiral Centre

Answer 37

A carbon atom attached to four different groups.

Question 38

Chromatogram

Answer 38

A visible record showing the result of separation of the different components of a mixture by chromatography.

Question 39

Delocalised electrons

Answer 39

Electrons that are shared between more than two atoms.