A2 Level Chemistry Terminology

Acid Dissociation Constant Ka

the acid dissociation constant of an acid (HA) - Ka = [H+(aq)][A-(aq)]/[HA(aq)] - Ka = 10^-pKa - pKa = -log (Ka)

1 of 171

Activation Energy

the minimum energy required to start a reaction by breaking bonds in the reactants

2 of 171

Addition Polymer

a very long molecular chain formed by repeated addition reactions of many unsaturated (C=C) alkene molecules (monomers)

3 of 171

Addition Reaction

a reaction in which a reactant is added to an unsaturated (C=C) molecule to make a saturated molecule

4 of 171

Aliphatic Hydrocarbon

a hydrocarbon where carbon atoms are joined together in straight or branched chains

5 of 171

Alkali

a base that dissolves in water forming OH- (aq) ions

6 of 171

Alkanes

the homologous series of organic chemical compounds with the general formula CnH2n+2

7 of 171

Alkylammonium Salt

a compound where the hydrogen(s) on an ammonium ion have been substituted by alkyl chains

8 of 171

Alkylation

addition of hydrocarbon chains to an organic compound

9 of 171

Alkyl Group

an alkane with a hydrogen atom removed, e.g. -CH3, C2H5 - R group

10 of 171

Amide

a class of compound with a functional group made of an acyl group, which is directly attached to an amine - NH2

11 of 171

Amount of Substance

the quanity whose unit is the mole - counting atoms

12 of 171

Amphoteric Chemicals

chemicals that can reacts with both acids and bases

13 of 171

Anion

a negatively charged ion

14 of 171

Anhydrous

a substance that contains no water molecules

15 of 171

Arrhenius Plot

a graph of ln K = ln A - Ea/RT - ln K against 1/T

16 of 171

Atomic Orbital

a region of space where it is likely that you will find electrons - each orbital can hold up to two electrons, with opposite spin

17 of 171

Atomic (Proton) Number

the number of protons in the nucleus of an atom

18 of 171

Average Bond Enthalpy

the mean energy needed for 1 mole of a given type of gaseous bonds to undergo homolytic fission

19 of 171

Avogadro Constant

the number of atoms per mole of the carbon-12 isotope (6.02 x 10^23 mol^-1)

20 of 171

Base

a chemical that will react with an acid

21 of 171

Benzene

a naturally occuring aromatic compound, which is a very stable planar ring structure with delocalised electrons

22 of 171

Benzene Derirative

a benzene ring that has undergone a substitution reaction

23 of 171

Boltzmann Distribution

the distribution of energies of molecules at a particular temperature, often shown as a graph

24 of 171

Bronsted-Lowry Acid

a proton (H+) donor

25 of 171

Bronsted-Lowry Base

a proton (H+) acceptor

26 of 171

Buffer Solution

a mixture that minimises pH changes on addition of small amounts of acid or base

27 of 171

Carbocation

an organic ion in which a carbon atom has a position charge

28 of 171

Catalyst

a substance that increases the rate of reaction without being used up in the process

29 of 171

Cation

a positively charge ion

30 of 171

Chemical Shift

the scale that compares the frequency of NMR absorption with the frequency of the reference peak of TMS

31 of 171

Chiral Carbon

a chrial carbon has four different groups attached to it

32 of 171

Chromatogram

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

33 of 171

Cis-Trans Isomerism

a type of E/Z isomerism where each carbon of the double C=C bond carries the same atom or group

34 of 171

Complex Ion

a transition metal ion bonded to one or more ligands by coordinate bonds/dative covalent bonds

35 of 171

Condensation Polymerisation

the chemical reaction to form a long chain molecule by elimination of a small molecule, e.g. water

36 of 171

Conjugate Acid-Base Pair

two species that transform into each other by gain or loss of a proton (H+)

37 of 171

Coordinate Bond/Dative Covalent Bond

a bond formed by a shared pair of electrons that has been provided by one of the bonding atoms only

38 of 171

Coordination Number

the total number of coordinate (dative covalent) bonds formed between a central metal ion and its ligands

39 of 171

Covalent Bond

a bond formed by a shared pair of electrons between nuclei

40 of 171

Curly Arrow

a symbol used in reaction mechanisms to show the movement of an electron pair

41 of 171

Degradable Polymer

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

42 of 171

Delocalised Electrons (e-)

electrons that are shared between more than two atoms, e.g. metallic bonding

43 of 171

Deuterium

an isotope of hydrogen and does not produce a signal in the proton (H+) NMR spectrum

44 of 171

Directing Effect

how a functional group attached directly to an aromatic ring affect which carbon atoms are more likely to undergo substitution

45 of 171

Displayed Formula

a formula which shows the relative positions of atoms and the bonds between them

46 of 171

Disproportionation

the oxidation and reduction of the same element in a redox reaction

47 of 171

Distillation

a technique used to separate miscible liquids or solutions

48 of 171

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 and all the chemical have their concentrations maintained

49 of 171

Electron Structure/Configuration

the arrangement of electrons in an atom or ion

50 of 171

Electrophile

an electron pair acceptor

51 of 171

Electrophilic Substitution

a substitution reaction where an electrophile is attracted to an electron rich atom or part of a molecule and a new covalent bond is formed by the electrophile accepting an electron pair

52 of 171

Elimination Reaction

an organic chemical reaction in which one reaction forms two products - small molecule, e.g. water, is released

53 of 171

Empirical Formula

the simplest whole number ratio of atoms of each element present in a compound

54 of 171

Enantiomer

an optical isomer

55 of 171

Endothermic

a reaction in which the enthalpy of the products is greater than the enthalpy of the reactants - heat taken in from surroundings (+) (up)

56 of 171

End Point

the point in titration at which there are equal concentrations of the weak acid and conjugate base forms of the indicator - colour at end point is midway between colours of acid and conjugate base forms

57 of 171

Enthalpy Cycle

a pictorial presentation showing alternative routes between reactants and products

58 of 171

Enthalpy Profile Diagram

a diagram of a reaction that allows you to compare the enthalpy of the reactants with the enthalpy of the products

59 of 171

Enthalpy (H)

the heat content that is stored in a chemical system

60 of 171

Entropy (S)

the quantitative measure of the degree of disorder in a system

61 of 171

Equilibrium Law

Kc =[products]/[reactants] *remember number in front is placed as a power

62 of 171

Equivalence Point

the point in a titration at which the volume of one solution has reacted exactly with the volume of the second solution = stochiometry of the reaction

63 of 171

Equivalent Carbon Atoms

carbon atoms bonded to the same atom - experience same magnetic field in the NMR spectrometer

64 of 171

Equivalent Protons

hydrogen atoms bonded to the same atoms - experience same magnetic field in the NMR spectrometer

65 of 171

Esterification

the chemical reaction which forms an ester

66 of 171

Exothermic

a reaction in which the enthalpy of the products is smaller than the enthalpy of the reactants - heat loss to the surroundins (-) (down)

67 of 171

E/Z Isomerism

a type of stereoisomerism that is caused by the restricted rotation around the double C=C bond - two different groups are attached to each carbon atom

68 of 171

First Electron Affinity

the enthalpy change accompanying the formation of 1 mole of gaseous 1- ions from gaseous atoms

69 of 171

First Ionisation Energy

the energy change that accompanies the removal of 1 mole of electrons from 1 mole of gaseous atoms

70 of 171

Free Energy Change (Gibbs)

the balance between enthalpy, entropy and temperature for a process - change in G = change in enthalpy (H) - ((Temperature (K) x (change in entropy (S)) - process is spontaneous when change in G = negative

71 of 171

Friedel-Crafts Reaction

a substitution reaction where hydrogen is exchanged for an alkyl or acyl chain - allow electrophilic substitution to occur on an aromatic ring

72 of 171

Functional Group

a group of atoms that is responsible for the characteristic chemical reactions of a compound

73 of 171

General Formula

the simplest algebraic formula for a homologous series

74 of 171

Geometric Isomers

molecules that have the same structural formula but a different arrangement in space

75 of 171

Giant Covalent Lattice

a 3D structure of atoms that are all bonded together by strong covalent bonds

76 of 171

Giant Ionic Lattice

a 3D structure of oppositely charged ions, held together by strong electrostatic forces of attraction - ionic bonds

77 of 171

Giant Metallic Lattice

a 3D structure of positive metal ions (cations) and delocalised electrons bonded together by strong metallic bonds

78 of 171

Group

a column in the periodic table - similar chemical properties - same number of outer shell electrons

79 of 171

Half-Life

the time taken for the concentration of a reactant to reduce by half

80 of 171

Hess' Law

states that the enthalpy change in a chemical reaction is independent of the route it takes

81 of 171

Heterogenous Equilibrium

an equilibrium in which species making up the reactants and products are in different physical states

82 of 171

Homogenous Equilibrium

an equilibrium in which all the species making up the reactants and products are in the same physical state

83 of 171

Homologous Series

a series of organic compounds that have the same functional group with successive members differing by -CH2

84 of 171

Hydrolysis

a chemical reaction where water is a reactant in a decomposition reaction

85 of 171

Intermediate

a species formed in one step of a multi-step reaction that is used up in a subsequent step, and is not seen as either a reactant or a product of the overall equation

86 of 171

Ion

a positively or negatively charged ion or (covalently bonded) group of atoms (molecular ion)

87 of 171

Ionic Bonding

the electrostatic attraction between oppositely charged ions

88 of 171

Ionic Product of Water - Kw

Kw = [H+(aq)][OH-(aq)] - 25 degrees celsius - Kw = 1x10^-14 mol^2 dm^-6

89 of 171

Isoelectric Point

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

90 of 171

Lattice Enthalpy (LE)

the enthalpy change that accompanies the formation of one mole of an ionic lattice from its gaseous ions under standard conditions

91 of 171

Le Chatelier's Principle

states that when a system in dynamic equilibrium is subjected to a change, the position of equilibrium will shift to minimise the change

92 of 171

Lewis Acid

an electron pair acceptor

93 of 171

Ligand

a molecule or ion that can donate a pair of electrons to the transition metal ion to form a coordinate bond

94 of 171

Ligand Substitution

a reaction in which one ligand in a complex ion is replaced by another ligand

95 of 171

Lone Pair

an outer-shell pair of electrons that is not involved in chemical bonding

96 of 171

Mass (nucleon) Number

the number of particles (protons and neutrons) in the nucleus of an atom

97 of 171

Mobile Phase

the phase that moves in chromatography, e.g. solvent

98 of 171

Model

a simplified version that allows us to makes predictions and understand observations more easily

99 of 171

Molar Mass (M)

the mass per mole of a substance - gmol^-1

100 of 171

Mole

the amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon-12 isotope

101 of 171

Mole Fraction

a measure of how much of a given substance is present in a reaction mixture (%)

102 of 171

Molecular Formula

shows the numbers and type of the atoms of each element in a compound

103 of 171

Molecular Ion - M+

the positive ion formed in mass spectrometry when a molecule loses an electron - M+ ion peak = Mr of compound

104 of 171

Monomers

small molecules that are used to make polymers

105 of 171

Neutralisation

a chemical reaction in which an acid and a base react together to produce a salt and water

106 of 171

Nitrile

an organic chemical with a -CN functional group

107 of 171

Nucleophile

a species that contains a lone pair of electrons of a negative charge and is attracted to positive areas of a molecule - donates a pair of electrons

108 of 171

Optical Isomers

molecules which are non-superimposable mirror images of each other - same chemical properties - interact with polarised light differently

109 of 171

Order

with respect to a reactant, the order is the power to which the concentration of the reactant is raised in the rate equation

110 of 171

Overall Order

the overall order of a reaction is the sum of the individual orders, m + n

111 of 171

Oxidation

loss of electrons - increase in oxidation number

112 of 171

Oxidation Number

a measure of the number of electrons that an atom uses to bond with atoms of another element - rules

113 of 171

Oxidising Agent

the species that is reduced in a reaction and causes another species to be oxidised [O] - e.g. potassium dichromate

114 of 171

Partial Pressure

the pressure an individual gaseous substance would exert if it occupied a whole reaction vessel on its own

115 of 171

Phase

a physically distinctive form of a substance - solid, liquid or gas

116 of 171

Phenols

a class of aromatic compounds where a hydroxyl group is directly attached to the aromatic ring

117 of 171

pH

-log[H+(aq)] / [H+(aq)] = 10^-pH

118 of 171

Pi Bond

sideways overlap of adjacent p-orbitals above and below the bonding carbon atoms

119 of 171

Polar Molecule

a molecule with an overall dipole, having taken into account any dipoles across bonds

120 of 171

Polymer

a large complex macromolecule made from small repeating units - monomers

121 of 171

Precipitation Reaction

the formation of a solid from a solution during a chemical reaction - two aqueous solutions mixed together

122 of 171

Qualitative Analysis

an observable change and does not involve observations using numerical values, e.g. colour change - bias - unreliable

123 of 171

Rate Constant - K

the constant that links the rate of reaction with the concentrations of the reactants raised to the powers of their orders in the rate equation

124 of 171

Rate-Determining Step

the slowest step in the reaction mechanism of a multi-step reaction

125 of 171

Rate Equation

rate = k[A]^m[B]^n - powers = orders with respect to the reactants

126 of 171

Rate of Reaction

the change in concentration of a reactant or a product per unit time

127 of 171

Reaction Mechanism

a series of steps that, together, make up the overall reaction; a model with steps to explain and predict a chemical reaction

128 of 171

Recrystallisation

a method for purifying organic compounds

129 of 171

Redox Reaction

a reaction in which both reduction and oxidation take place

130 of 171

Reducing Agent

the species that is oxidised in a reaction and causes another species to be reduced - [H] - e.g. H2SO4, NH4

131 of 171

Reduction

gain of electrons or decrease in oxidation number

132 of 171

Reflux

a technique used to stop reactions mixtures boiling dry - gases don't escape - condense back into liquids

133 of 171

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

134 of 171

Repeat Unit

the arrangement of atoms that occurs many times in a polymer - structure of a monomer - [ ]n

135 of 171

Retention Time

the time taken for a component to travel from the inlet to the detector in a gas chromatograph

136 of 171

Retro-Synthesis

where the synthetic route is designed by looking at the target molecule and working backwards

137 of 171

Rf Value

a comparison between how far a component has moved compared to the solvent in thin layer chromatography

138 of 171

Salt

any chemical compound formed from an acid when a H+ ion from the acid has been replaced by a metal ion or another positive ion - metal ion or ammonium ion NH4+

139 of 171

Saturated Hydrocarbon

a hydrocarbon chain with single C-C bonds only

140 of 171

Second Electron Affinity

the enthalpy change accompanying the formation of 1 mole of gaseous 2- ions from 1 mole of gaseous 1- ions

141 of 171

Second Ionisation Energy

the energy change that accompanies the formation of 1 mole of gaseous 2+ ions from 1 mole of gaseous 1+ ions

142 of 171

Shell

a group of atomic orbitals with the same principal quantum number - n - energy level

143 of 171

Skeletal Formula

a simplified structural formula drawn by removing hydrogen atoms from alkyl chains

144 of 171

Spectator Ions

ions that are present but that play no part in a chemical reaction - not shown in ionic equations

145 of 171

Spin-Spin Coupling

the interaction between spin states of non-equivalent nuclei that results in a group of peaks in an NMR spectrum

146 of 171

Standard Conditions

standards set for experimental measurements to allow comparisons to be made between different sets of data - 100kPa and 298K (25 degrees celsius)

147 of 171

Standard Electrode Potential of a Half Cell (E)

the e.m.f of a half cell compared with a standard hydrogen half-cell, measured at 298K with solution concentrations of 1mol dm^-3 and a gas pressure of 100kPa

148 of 171

Standard Enthalpy Change of Atomisation (at)

the enthalpy change that accompanies the formaiton of 1 mole of gaseous atoms from the elements in standard states

149 of 171

Standard Enthalpy Change of Formation (f)

the enthalpy change that accompanies the formation of 1 mole of a compound from its elements

150 of 171

Standard Enthalpy Change of Hydration (hyd)

the enthalpy change that takes place when dissolving 1 mole of gaseous ions in water

151 of 171

Standard Enthalpy Change of Solution (sol)

the enthalpy change that takes place when one mole of solute is completely dissolved in water under standard conditions

152 of 171

Standard Entropy - S

the entropy content of one mole of a substance under standard conditions

153 of 171

Standard Entropy Change of Reaction (S)

the entropy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions, all reactants and products being in their standard states

154 of 171

Stationary Phase

the phase that does not move in chromatography, e.g. paper

155 of 171

Stem

the longest carbon chain present in an organic molecule

156 of 171

Stereoisomers

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

157 of 171

Stoichiometry

the molar relationship between the relative quantities of substances taking part in a reaction

158 of 171

Strong Acid

an acid that completely dissociates in solution

159 of 171

Structural Formula

provides the minimum detail to show the arrangment of atoms in a molecule

160 of 171

Structural Isomers

compounds with the same molecular formula but different structural formula

161 of 171

Sub-Shell

a group of the same type of atomic orbitals (s,p,d,f) within a shell - s = 2 electrons / p = 6 electrons / d = 10 electrons / f = 14 electrons

162 of 171

Substitution Reaction

when an atom or group of atoms is replaced by a different atom or group of atoms

163 of 171

Synthetic Route/Pathway

a series of reactions that can be used to change a starting chemical into a target molecule

164 of 171

TMS

an internal standard for both carbon-13 and proton (H+) NMR spectroscopy

165 of 171

Transition Element/Metal

a d-block element that has an incomplete d-sub-shell as a stable ion

166 of 171

Unsaturated Hydrocarbon

a hydrocarbon chain with containing multiple carbon-to-carbon bonds, e.g. double or triple carbon bonds

167 of 171

Van der Waals' Forces

a type of intermolecular bonding that includes permanent dipole-dipole bonding and induced dipole-dipole interactions (London forces)

168 of 171

Water of Crystallisation

water molecules that form an essential part of the crystalline structure of a compound

169 of 171

Weak Acid

an acid that partially dissociates in solution

170 of 171

Zwitterion

an internal salt, with no charge, formed by the donation of a proton (H+) from a carboxylic acid functional group to the amine functional group (-NH2) in an amino acid

171 of 171

Get Revising

A2 Level Chemistry Terminology

Other cards in this set

Card 2

Front

Back

Card 3

Front

Back

Card 4

Front

Back

Card 5

Front

Back

Comments

Similar Chemistry resources:

Other cards in this set

Card 2

Front

Back

Card 3

Front

Back

Card 4

Front

Back

Card 5

Front

Back

Comments

Related discussions on The Student Room

Similar Chemistry resources: