Definitions for RPA Flashcards
1
Q
Addition polymer
A
A very long molecular chain, formed by repeated addition reactions of many unsaturated alkene molecules
2
Q
Addition reaction
A
A reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule
3
Q
Alicyclic hydrocarbon
A
A hydrocarbon with carbon atoms joined together in a ring structure
4
Q
Aliphatic hydrocarbon
A
A hydrocarbon with carbon atoms joined together in straight or branched chains
5
Q
Alkanes
A
The homologous series with the general formula: CnH2n+2
6
Q
Alkyl group
A
An alkane with a hydrogen atom removed e.g. CH3, C2H5, any alkyl group is often shown as ‘R’
7
Q
Amount of substance
A
The quantity whose unit is the mole. Chemists use amount of substance as a means of counting atoms
8
Q
Anhydrous
A
A substance that contains no water molecules
9
Q
Anion
A
A negatively charged ion
10
Q
Atom economy
A
Molecular mass of the desired product/sum of molecular masses of all products X 100%
11
Q
Atomic number
A
The number of protons in the nucleus of an atom
12
Q
Atomic orbital
A
A region within an atom that can hold up to 2 electrons with opposite spins
13
Q
Avagadros constant
A
The number of atoms per mole of carbon – 12 isotope (6.02×10 to the 23)
14
Q
Biodegradable substance
A
A substance that is broken down naturally in the environment by other living organisms
15
Q
Biodegradable polymers
A
A polymer that breaks down completely into carbon dioxide and water
16
Q
Boltzman distribution
A
A diagram showing the distribution of energies of the molecules at a particular temperature
17
Q
Carbanion
A
And organic ion in which a carbon atom has a negative charge
18
Q
Carbocation
A
An organic ion in which a carbon atom has a positive charge
19
Q
Catalyst
A
A substance that increases the rate of a chemical reaction without being used up in the process
20
Q
Cation
A
A positively charged ion
21
Q
Chemical shift
A
A scale that compares the frequency of an NMR absorption with the frequency of the reference TMS at zero ppm
22
Q
Chiral carbon
A
A carbon atom attached to 4 different atoms or groups of atoms
23
Q
Chromatogram
A
A visible record showing the result of separation of the components of a mixture by chromatography
24
Q
Cis-trans isomerism
A
A special type of E/Z isomerism in which each carbon of the C=C double bond carries the same atom or group: the cigs isomer (Z isomer) has that group on each carbon on the same side; the teams isomer (E isomer) has that group on each carbon on different sides
25
Condensation reaction
A reaction in which two small molecules react together to form a larger molecule with the elimination of a small molecule such as water
26
Covalent bond
A bond formed by shared pair of electrons
27
Cracking
The breaking down of long chained saturated hydrocarbons to form a mixture of short chain alkanes and Alkenes
28
Curly arrow
A symbol used in reaction mechanisms to show the movement of an electron pair during the breaking or formation of a covalent bond
29
Dative covalent
A shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only; also called a coordinate bond
30
Degradable polymers
A polymer that breaks down into smaller fragments when exposed to light, heat or moisture
31
Dehydration
And elimination reaction in which water is removed from a saturated molecule to make an unsaturated molecule
32
Delocalised electrons
Electrons that are shared between more than two atoms
33
Dipole-dipole force
An attractive force between permanent dipoles in neighbouring polar molecules
34
Displacement reaction
A reaction in which a more reactive element displaces a less reactive element from an aqueous solution of its ions
35
Displayed formula
A formula showing the relative positioning of all the atoms in a molecule and the bonds between them
36
Disproportionation
The oxidation and reduction of the same species in a redox reaction
37
Electron shielding
The repulsion between electrons in different inner shells. Shielding reduces the net attractive force from the positive nucleus on the outer shell electrons
38
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 restricted rotation of the C=C double bond
39
Electronegativity
A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond
40
Electrophile
And atom (or group of atoms) which is attracted to an electron rich Centre or atom, where it accepts a pair of electrons to form a new covalent bond
41
Electrophilic substitution
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
42
Elimination reaction
The removal of a molecule from saturated molecule to make an unsaturated molecule
43
Empirical formula
The simplest whole number ratio of atoms of each element present in a compound
44
Enantiomers
Stereoisomers that are non-superimposable mirror images of each other; also called optical isomers
45
Endothermic
A reaction in which the Enthalpy of the products is greater than the enthalpy of the reactants. Resulting in heat being taken in from the surroundings
46
Esterification
The reaction of an alcohol with a carboxylic acid to produce an ester and water
47
Exothermic
A reaction in which the enthalpy of the products is smaller than the enthalpy of the reactants, resulting in heat loss to the surroundings.
48
Fragmentation
The process in mass spectrometry that causes a positive ion to split into pieces, one of which is a positive fragment Ion
49
Functional group
The part of the organic molecule responsible for its chemical reactions
50
General formula
The simplest algebraic formula of a member of a homologous series.
51
Giant covalent lattice
A three-dimensional structure of atoms, bonded together by strong covalent bonds
52
Giant ionic lattice
Three-dimensional structure of oppositely charged ions, bonded together by strong ionic bonds
53
Greenhouse effect
The process in which the absorption and subsequent emission of infrared radiation by atmospheric gases warms the lower atmosphere and the planets surface
54
Heterogeneous catalysis
A reaction in which the catalysts have a different physical state from the reactants; frequently reactants are gases whilst the catalyst is a solid
55
Heterogeneous equilibrium
An equilibrium in which the species making up the reactants and products are in different physical states
56
High density lipoprotein
A type of lipoprotein that can remove cholesterol from the arteries and transport it back to the liver for excretion or re-utilisation
57
Heterolytic fission
The breaking of a covalent bond with both of the bonded electrons going to on atom, forming a cation and an anion
58
Homogeneous catalysis
A reaction in which the catalyst and reactants are in the same physical state, which is most frequently the aqueous or gaseous state
59
Homogeneous equilibrium
And equilibrium in which all the species making up the reactants and products are in the same physical state
60
Homologous series
A series of organic compounds with the same functional group but with each successive member differing by CH2
61
Homolytic fission
The breaking of a covalent bond with one of the bonded electrons going to each atom, forming two radicals
62
Hydrated
A crystalline compound containing water molecules
63
Hydrogen bond
A strong dipole dipole attraction between an electron deficient hydrogen atom on one molecule and a lone pair of electrons on a highly electronegative atom on a different molecule
64
Hydrolysis
A reaction with water or hydroxide ions and the breaks chemical compounds into two compounds
65
Initial rate of reaction
The change in concentration of the reactants or products per unit time at the start of the reaction: T = 0
66
Initiation
The first step in a radical substitution in which the free radicals are generated by ultraviolet radiation
67
Intermediates
A species formed in one step of a multistep reaction that is used up in a subsequent step, and is not seen as either a reactant or product of the overall equation
68
Intermolecular force
And attractive force between neighbouring molecules. Intermolecular forces can be Van der Waals forces, dipole dipole forces or hydrogen bonding
69
Giant metallic lattice
Three-dimensional structure of positive ions and delocalised electrons, bonded together by strong metallic bonds
70
Ion
Positive people negatively charged atom or (covalently bonded) group of atoms
71
Ionic bonding
The electrostatic attraction between oppositely charged ions
72
Isotope
Atoms of the same element with different numbers of neutrons and different masses
73
Low-density lipoprotein
A type of lipoprotein responsible for carrying cholesterol and triglycerides from the liver to the tissues
74
Mass (nucleon) number
The number of particles, protons and neutrons,in the nucleus
75
Mechanism
Sequence of steps showing the path taken by electrons in a reaction
76
Metallic bond
The electrostatic attraction between positive metal ions and delocalised electrons
77
Mobile phase
The phase that moves in chromatography
78
Molar mass
The mass per mole of a substance. Units: gmol^-1
79
Mole
The amount of any substance containing as many elementary particles as there are carbon atoms in exactly 12 g of carbon 12 isotope
80
Molecular formula
The actual number of atoms of each element in a molecule
81
Molecular ion, M+
The positive ions formed in mass spectrometry when a molecule loses an electron
82
Molecule
A small group of atoms held together by covalent bonds
83
Monomer
Small molecule that combines with many other monomers to form a polymer
84
Nucleophile
An atom (or group of atoms) which is attracted to an electron deficient centre or atom, where it donates a pair of electrons to form a new covalent bond
85
Optical isomers
Stereoisomers that are non-superimposable mirror images of each other; also called enantiomers
86
Peptide
A compound containing amino acid's linked by peptide bonds. Often the number of amino acid is indicated by the prefix, di, trip or tetra
87
Percentage yield
Actual amount in mol of product/ theoretical amount in lol of product
88
Permanent dipole
A small charge difference across a bond resulting from a different electronegativities of the bonded atoms
89
Pharmacological activity
The beneficial or adverse affects of a drug on living matter
90
Phase
A physically distinctive form of a substance, such as the solid, liquid and gaseous state of matter
91
Pi bond
The reactive part of the double bond formed above and below the plane of the bonded atoms by sideways overlap of P orbitals
92
Polar covalent bond
A bond with a permanent dipole
93
Polar molecule
A molecule with an overall dipole, having taken into account any dipoles across bonds
94
Polymer
Along molecular chain built up from monomer units
95
Precipitation reaction
The formation of a solid from a solution during a chemical reaction. Precipitates are often formed when two aqueous solutions are mixed together
96
Principal quantum number
A number representing the relative overall energy of each orbital, which increases with distance from the nucleus. The sense of orbitals with the same n-value are referred to as the electron shells or energy levels
97
Propagation
The two repeat steps in radical substitution which build up the products in the chain reaction
98
Radical
A species with an unpaid electron
99
Reaction mechanism
A series of steps that, together, make up the overall reaction
100
Relative atomic mass
The weighted mean mass of an atom of an element compound with 1/12 of the mass of an atom of carbon 12
101
Relative formula mass
The weighted mean mass of the formula unit of a compound compared with 1/12 of the mass of an atom of carbon 12
102
Relative isotopic mass
The mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon 12
103
Relative molecular mass
The weighted mean mass of a molecule of a compound compared with 1/12 of the mass of an atom of carbon 12
104
Repeat unit
The specific arrangement of atoms that occurs in the structure over and over again. Repeat units are included in brackets, outside which is the symbol n
105
Retention time
Gas chromatography, it is the time for a component to pass from the column inlet to the detector
106
RF value
Distance moved by component/distance moved by solvent front
107
Salt
A chemical compound formed from an acid, when an H plus ions from the acid has been replaced by a metal ion or another positive ion, such as the ammonium ion NH4 plus
108
Saturated hydrocarbon
A hydrocarbon with single bonds only
109
Shell
A group of atomic orbitals with the same principal quantum number also known as a main energy level
110
Simple molecular lattice
The three-dimensional structure of molecules, bonded together by weak intermolecular forces
111
Skeletal formula
A simplified organic formula, with hydrogen atoms removed from alkyl chains. Leaving just a carbon skeleton and associated functional groups
112
Spin-spin coupling
The interaction between Spin states of non-equivalent nuclei that results in a group of peaks in an NMR spectrum
113
Stationary phase
The phase that does not move in chromatography
114
Stem
The longest carbon chain present in an organic molecule
115
Stereoisomers
Species with the same structural formula but with a different arrangement of the atoms in space
116
Stoichiometry
The molar relationship between the relative quantities of substances taking part in a reaction
117
Stratosphere
The second layer of the Earth's atmosphere, containing the ozone layer between about 10 km and 50 km above the earths surface
118
Structural formula
The formula showing the minimal detail for the arrangement of atoms in a molecule
119
Structural isomers
Molecules with the same molecular formula but with a different structural arrangement of atoms
120
Sub shell
A group of the same type of atomic orbitals (S, P, D) within a shell
121
Substitution reaction
A reaction in which an atom or group of atoms is replaced with a different atom or group of atoms
122
Termination
The step at the end of the radical substitution when two radicals combined to form a molecule
123
Thermal decomposition
The breaking up of a chemical substance with heat into at least two chemical substances
124
Troposphere
The lowest layer of the Earth's atmosphere, extending above the Earth's surface up to about 7 km above the poles and to about 20 km above the tropics
125
Unsaturated hydrocarbon
Hydrocarbons containing multiple carbon to carbon bonds
126
Valence shell
The outermost shell of an atom, which contains the electrons most likely to react and bond to other atoms
127
Van der waals' forces
And attractive force between instantaneous dipole is and induced dipoles in the neighbouring molecules
128
Volatility
The ease with which a liquid turns into a gas. Volatility increases as boiling point decreases
129
Water of crystallisation
Water molecules that form an essential part of the crystalline structure of a compound
130
Zwitterion
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. As both charges are present there is no overall charge
