ALL DEFINITIONS Flashcards
(122 cards)
1
Q
Acid
A
A species that is a proton donor.
2
Q
Activation energy
A
The minimum energy required to start a reaction by the breaking of bonds.
3
Q
Addition polymer
A
A very long molecular chain formed by repeated addition reactions of many unsaturated alkene molecules
4
Q
Addition reaction
A
A reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule.
5
Q
Adsorption
A
The process that occurs when a gas, liquid or solute is held to the surface of a solid or a liquid(rare).
6
Q
Alicyclic hydrocarbon
A
A hydrocarbon with carbon atoms joined together in a ring structure
7
Q
Aliphatic hydrocarbon
A
A hydrocarbon with carbon atoms joined together in a straight or branched chain
8
Q
Alkali
A
A type of base that dissolves in water forming hydroxide ions, (OH-, aqueous ions)
9
Q
Alkanes
A
The homologous series with the general formula CnH2n+2
10
Q
Alkyl group
A
An alkane with a hydrogen atom removed (often denoted R)
11
Q
Amount of Substance
A
The quantity with unit mole, used for counting atoms
12
Q
Anhydrous
A
A substance that contains no water molecules
13
Q
Anion
A
A negatively charged ion (no one likes onions-negative anions)
14
Q
Atom economy
A
(Mr of desired product)/(Mr of all products) *100%
15
Q
Atomic orbital
A
A region within an atom that can hold up to two electrons, with opposite spins
16
Q
Atomic number
A
Number of protons in the nucleus of an atom
17
Q
Average bond enthalpy
A
Average enthalpy change that takes place when 1 mol of a type of bond in the molecules of a gas are broken by homolytic fission
18
Q
Avogadro constant (Na)
A
The number of atoms per mole of the carbon-12 isotope (6.02 *10^23 mol^-1)
19
Q
Base
A
A species that is a proton acceptor
20
Q
Biodegradable material
A
A substance that is broken down naturally in the enviroment by living organisms
21
Q
Carbanion
A
An organic ion in which a carbon atom has a negative charge
22
Q
Carbocation
A
An organic ion in which a carbon atom has a positive charge
23
Q
Catalyst
A
A substance that increases the rate of chemical reaction without being used up in the process
24
Q
Cation
A
A positively charged ion (everyone likes cats)
25
Cis-trans isomerism
Type of E/Z isomerism, hydrogen and non hydrogen atom on each C in C=C, CIS: hydrogen on same side of bond, TRANS: hydrogen on opposite sides of bond
26
Concentration
The amount of solute, in mol, per 1 dm^-3 of solution
27
Coordinate bond
A shared pair of electrons which has been provided by only one of the bonding atoms (aka dative covalent)
28
Covalent bond
A bond formed by a shared pair of electrons
29
Cracking
The break down of a long chained saturated hydrocarbon to form a mixture of shorter chained alkanes and alkenes
30
Curly arrow
Symbol used in reaction mechanisms to show the movement of an electron pair in the breaking or formation of a covalent bond
31
Dative covalent
A shared pair of electrons which has been provided by only one of the bonding atoms
32
Dehydration
An elimination reaction in which water is removed from a saturated molecule to make an unsaturated molecule
33
Delocalised electrons
Electrons that are shared between more than two atoms
34
Displacement reaction
A reaction in which a more reactive element displaces a less reactive element from an aqueous solution of its ions
35
Disproportionation
The oxidation and reduction of the same element in a redox reaction
36
Dynamic equilibrium
The equilibrium that exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction
37
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 due to restricted rotation of C=C bond
38
Electron configuration
The arrangement of electrons in an atom
39
Electronegativity
A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond
40
Electron sheilding
The repulsion between electrons in different inner shells, sheilding reduces the net attractive force from the positive nucleus on the outer shell electrons
41
Electrophile
An atom, or group, that is attracted to an electron dense space or atom, where it accepts a pair of electrons to form a new covalent bond
42
Electrophillic addition
A type of addition reaction in which an electrophile is attracted to an electron dense atom, it accepts an electron pair to form a new covalent bond
43
Elimination reaction
The removal of a molecule from a saturated molecule to make an unsaturated molecule
44
Emperical formula
The simplest whole number ratio of atoms of each element in a compound
45
Endothermic reaction
A reaction in which the enthalpy of the products is greater than the enthalpy of the reactants, results in heat being taken in from the surroundings
46
Enthalpy
The heat content that is stored in a chemical system
47
Standard enthalpy change of combustion
The enthalpy change that takes place when one mole of a substance reacts completely with oxygen under standard conditons, all reactants and products in their standard states
48
Standard enthalpy of formation
The enthalpy change that takes place when one mole of a compound is formed from its pure elements in their standard states under standard conditions
49
Standard enthalpy of reaction
The enthalpy change of a reaction in molar quantities expressed in a chemical equation under standard conditions
50
Enthalpy cycle
Diagram showing alternative routes between reactants and products to allow indirect determination of enthalpy change (from other known enthalpy changes using Hess' Law)
51
Enthalpy profile diagram
Diagram comparing enthalpy levels of reactants and products in a reaction
52
Esterification
The reaction of an alcohol with a carboxylic acid to produce an ester and water
53
Exothermic reaction
A reaction in which the enthalpy of the products is smaller than the enthalpy of the reactants, results in heat loss to surroundings
54
Fractional Distillation
The seperation of components in a liquid mixture into fractions which differ in boiling point by distillation, using a fractionating column
55
Fragmentation
The process in mass spectrometry that cause a postive ion to split into pieces, one of which is a positive fragment ion
56
Functional group
The part of the organic molecule responsible for its chemical properties and reactions
57
General formula
The simplest algebraic formula of a member of a homologous series
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Giant covalent lattice
A 3D structure of atoms, bonded together by strong covalent bonds
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Giant ionic lattice
A 3D structure of oppositely charged ions, bonded by strong ionic bonds
60
Giant metallic lattice
A 3D structure of positive ions and delocalised electrons, bonded together by strong metallic bonds
61
Greenhouse effect
Process in which the absorption and subsequent emission of infrared radiation by the atmospheric gases warms the lower atmosphere and planet's surface
62
Hess' Law
If a reaction can take place by more than one route and the intital and final conditions are the same, the total enthalpy along each route will be the same
63
Heterogeneous catalysis
A reaction in which the catalyst has a different physical state to the reactants
64
Homogeneous catalysis
A reaction in which the catalyst and reactants are in the same physical state
65
Heterolytic fission
Breaking of a covalent bond with both of the bonded electrons going to one of the atoms, forming a cation and anion
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Homolytic fission
Breaking of a covalent bond with one of the bonded electrons going to each atom, forming two radicals
67
Homologous series
A series of organic compounds with the same functional group, but with each sucessive member differing by CH2
68
Hydrated
Crystalline and containing water molecules
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Hydrogen bond
A strong dipole attraction between an electron deficient hydrogen atom on one molecules and a lone pair of electrons on a highly electronegative atom of a different molecule
70
Hydrolysis
A reaction with water or aqueous hydroxide ions that breaks a chemical compound into two compounds
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Initiation
The first step in radical substitution where radicals are generated by UV radiation
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Intermolecular forces
Attractive force between neighbouring molecules: induced dipole/permenant dipole/ hydrogen bonds
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Ionic bonding
Electrostatic attraction between oppositely charged ions
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First ionisation energy
The energy required to removes one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions
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Second ionisation energy
The energy required to remove one electron from each ion in one mole of gaseous 1+ ions to from one mole of gaseous 2+ ions
76
Isotope
Atoms of the same element with a different number of neutrons and different masses
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le Chatelier's principle
When a system in dynamic equilibrium is subjected to a change the, the position of equilibrium will shift to minimise the change
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Limting reagent
The substance in a chemical reaction that runs out first
79
Lone pair
An outer-shell pair of electrons that is not involved in chemical bonding
80
Metallic bond
The electrostatic attraction between positive metal ions and decolised electrons
81
Molar volume
The volume per mole of gas, units dm^3 mol^-1, at RTP molar volume is 24 dm^3 mol^-1
82
Mole
The amount of any substance containing as many particles as there are carbon atoms in 12g of carbon-12
83
Nucleophile
An atom (or group of atoms) that is attracted to an electron deficient center or atom, where it donates a pair of electrons to form a new covalent bond
84
Oxidation
Loss of electrons or an increase in oxidation number
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Oxidising agent
A reagent that oxidises (takes electons from) another species
86
Percentage yeild
(Actual mol of product)/ (theoretical mol of product) *100%
87
Periodicity
A repeating pattern or trend shown across periods
88
Permenant dipole
A small charge difference across a bond resulting from a difference in electronegativity of bonded atoms
89
Permanent dipole-dipole force
An attractive force between permenant dipoles in neighbouring polar molecules
90
Pi - bond
The reactive part of a double bond, formed above and below the plane of the bonded atoms by sideways overlap of p-orbitals
91
Polar covalent bond
A bond with a permanent dipole
92
Polar molecule
A molecule with an overall dipole, accounting for dipoles across bonds
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Precipitation reaction
The formation of a solid from a solution during a chemical reaction. Precipitates are often formed when two aqueous solutions are mixed
94
Principal quantum number, n
Number representing the relative overall energy of each orbital, increases with distance from the nucleus, sets of orbitals with the same n value are referred to as energy levels
95
Propogation
The two repeated step in radical substitution that build up the products in a chain reaction
96
Redox reaction
A reaction in which both reduction and oxidation take place
97
Reducing agent
A reagent that reduces (adds electrons to) another species
98
Reflux
Continual boiling and condensing of a reaction mixture to ensure that the reaction takes place fully between reactants and intermediates
99
Relative atomic mass, Ar
The weighted mean mass of an atom of an element compared with 1/12 the mass of a carbon 12 atom
100
Relative formula mass
The weighted mean mass of a formula unit compared with 1/12 the mass of a carbon-12 atom
101
Relative isotopic mass
The mass of an atom of an isotope compared with 1/12 the mass of a carbon-12 atom
102
Salt
A chemical compound formed from an acid when a H+ ion from the acid has been replaces by a metal ion of other positive ion
103
Saturated hydrocarbon
A hydrocarbon with single bonds only
104
Shell
A group of atomic orbitals with the same principal quantum number
105
Simple molecular lattice
A 3D structure of molecules, bonded together by weak intermolecular forces
106
Species
Any type of particle that takes part in a chemical reaction
107
Specific heat capacity
The energy required to raise the temperature of 1g of a substance by 1*C
108
Spectator ion
Ions that are present but take no part in a chemical reaction
109
Standard conditions
A pressure of 100kPa (1 atm), a temp of 298K (25*C), conc of 1 mol dm^-3
110
Standard solution
A solution of known concentration, standard solutions used in titrations to determine unknown information about another substance
111
Standard state
The physical state of a substance under standard conditons
112
Stereoisomers
Compounds with the same structual formula but with a different arrangement of the atoms in space
113
Stoichiometry
The molar relationship between the relative quantities of substances taking part in a reaction
114
Stratosphere
The second layer of the Earth's atmosphere, containing the 'ozone layer', 10-50km above Earth
115
Structural isomers
Molecules with the same molecular formula but with different structural arrangements of atoms
116
Substitution reaction
A reaction in which an atom or group of atoms is replaced with a different atom or group of atoms
117
Termination
The end step of radical substitution when two radicals combine to form a molecule
118
Thermal decomposition
The breaking up of chemical substance with heat into atleast 2 products
119
Unsaturated hydrocarbon
A hydrocarbon containing carbon to carbon multiple bonds
120
Van deer Waal's forces
Very weak attractive forces between induced dipoles in neighbouring molecules (induced dipole)
121
Volatility
The ease with which a liquid turns into a gas, volatility increases as boiling point decreases
122
Water of crystallisation
Water molecules that form an essential part of the crystalline structure of a compound
