A2 Chemistry Definitions

Front 1

Delocalised electrons

Back 1

_______ are shared between more than two atoms

Front 2

An addition reaction

Back 2

___________ is one in which a reactant is added to an unsaturated molecule to make a saturated molecule

Front 3

A substitution reaction

Back 3

___________ is one in which an atom or group of atoms is replaced with a different atom or group of atoms

Front 4

An electrophile

Back 4

is an atom or group of atoms that is attracted to an electron rich centre, where it accepts a pair of electrons to form a new covalent bond.

Front 5

Electrophilic substitution

Back 5

is a type of substitution reaction in which an electrophile is attracted to an electron rich centre or atom, where it accepts a pair of electrons to form a new covalent bond.

Front 6

A reaction mechanism

Back 6

is a series of steps that, together, make up the overall reaction.

Front 7

A curly arrow

Back 7

is a symbol used in reaction mechanisms to show the movement of an electron pair in the breaking or formation of covalent bonds.

Front 8

The functional group

Back 8

is the part of an organic molecule responsible for its chemical reactions

Front 9

Electronegativity

Back 9

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

Front 10

The stem

Back 10

is the longest carbon chain present in an organic molecule

Front 11

A suffix

Back 11

is the part of the name added after the stem

Front 12

A redox reaction

Back 12

is one in which both reduction and oxidation take place

Front 13

Reflux

Back 13

is the continual boiling and condensing of a reaction mixture to ensure that the reaction takes place without the contents of the flask boiling dry

Front 14

A nucleophile

Back 14

is an atom or group of atoms attracted to an electron deficient centre, where it donates a pair of electrons to form a new covalent bond

Front 15

Esterification

Back 15

is the reaction of an alcohol with a carboxylic acid to produce an ester and water

Front 16

Hydrolysis

Back 16

is a reaction with water or hydroxide ions that breaks a chemical compound into two compounds

Front 17

Low-density lipoprotein (LDL)

Back 17

is responsible for carrying cholesterol and triglycerides from the liver to the tissues

Front 18

High-density lipoprotein (HDL)

Back 18

can remove cholesterol from the arteries and transport it back to the liver for excretion or re-utilisation

Front 19

A peptide

Back 19

is a compound made of amino acids linked by peptide bonds.

Front 20

A zwitterion

Back 20

is a dipolar ionic form of an amino acid that is formed by the donation of a hydrogen ion from the carboxyl group to the amino group. Because both charges are present, there is no overall charge.

Front 21

The isoelectric point

Back 21

is the pH value at which the amino acid exists as a zwitterion

Front 22

Stereoisomers

Back 22

are species with the same structural formula but with a different arrangement of the atoms in space

Front 23

A chiral carbon

Back 23

is a carbon atom attached to four different atoms or groups of atoms

Front 24

Optical isomers (or enantiomers)

Back 24

are stereoisomers that are non-superimposable mirror images of each other

Front 25

Condensation

Back 25

is a reaction in which two small molecules react together to form a larger molecule, with the elimination of a smaller molecule such as water

Front 26

The repeat unit

Back 26

is the specific arrangement of atoms that occurs in the structure over and over again.

Front 27

A biodegradable polymer

Back 27

is a polymer that breaks down completely into carbon dioxide and water

Front 28

A degradable polymer

Back 28

is a polymer that breaks down into smaller fragments when exposed to light, heat or moisture

Front 29

Pharmacological activity

Back 29

is the beneficial or adverse effects of a drug on living matter

Front 30

A phase

Back 30

is a physically distinctive form of a substance, such as the solid, liquid and gaseous states of ordinary matter

Front 31

The mobile phase

Back 31

is the phase that moves in chromatography

Front 32

The stationary phase

Back 32

is the phase that does not move in chromatography

Front 33

Adsorption

Back 33

is the process by which a solid holds molecules of a gas or liquid or solute as a thin film on the surface of a solid or, more rarely, a liquid

Front 34

A chromatogram

Back 34

is a visible record showing the result of separation of the components of a mixture by chromatography

Front 35

Rf = ?

Back 35

distance moved by component
__________________________

distance moved by solvent front

Front 36

Retention time in gas chromatography

Back 36

is the time for a component to pass from the column inlet to the detector

Front 37

Chemical shift

Back 37

δ, is a scale that compares the frequency of an NMR absorption with the frequency of the reference peak TMS at δ = 0 ppm.