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| 5985499093 | Activation Energy | The minimum energy required to start a reaction by breaking bonds in the reactants | 0 | |
| 5985500643 | Addition Polymer | A very long molecular chain formed by repeated addition reactions of many unsaturated alkene molecules | 1 | |
| 5985502772 | Addition Reaction | A reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule | 2 | |
| 5985508911 | Acid Dissociation Constant | Ka= [H+(aq)][A-(aq)]/[HA(aq)] | 3 | |
| 5985521899 | Aliphatic Hydrocarbon | A hydrocarbon where carbon atoms are joined together in straight or branched chains | 4 | |
| 5985523014 | Alkali | A base that dissolves in water forming OH- ions | 5 | |
| 5985523698 | Alkanes | The homologous series with general formula CnH2n+2 | 6 | |
| 5985526779 | Alkylammonium salt | A compound where the hydrogen's on an ammonium ion have been substituted by alkyl chains | 7 | |
| 5985529325 | Alkylation | Addition of hydrocarbon chains to an organic compound | 8 | |
| 5985530837 | Alkyl group | An alkane with a hydrogen atom removed e.g. CH3, C2H5 | 9 | |
| 5985531784 | Amide | A compound with a functional group made of an alcyl group, which is directly attached to an amine |  | 10 |
| 5985534940 | Amphoteric chemicals | Chemicals that can react with both acids and bases | 11 | |
| 5985536116 | Anion | A negatively charged ion | 12 | |
| 5985536447 | Anhydrous | A substance that contains no water molecules | 13 | |
| 5985537573 | Arrhenius plot | A graph of lnK = lnA - Ea/R x 1/T |  | 14 |
| 5985539967 | Atomic Orbital | A region of space where you will likely find electrons. Each orbital can hold 2 electrons, with opposite spins | 15 | |
| 5985542285 | Atomic number | The number of protons in the nucleus of an atom |  | 16 |
| 5985543119 | Average bond enthalpy | The mean energy needed for 1 mole of a given type of gaseous bonds to undergo homolytic fission | 17 | |
| 5985546058 | Avogadro constant | The number of atoms per mole of the carbon-12 isotope (6.02x10^23) | 18 | |
| 5985547609 | Base | A chemical that will react with an acid | 19 | |
| 5985549732 | Benzene | A naturally occurring aromatic compound, which is very stable planar ring structure with delocalized electrons |  | 20 |
| 5985555220 | Benzene Derivative | A benzene ring that has undergone a substitution reaction | 21 | |
| 5985556612 | Boltzman Distribution | The distribution of energies of molecules at a particular temperature |  | 22 |
| 5985558192 | Bronsted-Lowry acid | A proton donor | 23 | |
| 5985560735 | Bronsted- Lowry base | A proton acceptor | 24 | |
| 5985563428 | Buffer solution | A mixture that minimizes pH changes on addition of small amounts of acid or base | 25 | |
| 5985565290 | Carbocation | An organic ion in which a carbon atom has a positive charge | 26 | |
| 5985567250 | Catalyst | A substance that increases the rate of a reaction by providing an alternative route to start the reaction with lower activation energy, without being used up in the process | 27 | |
| 5985570176 | Cation | A positively charged ion | 28 | |
| 5985570820 | Chemical Shift | The scale that compares the frequency of NMR absorption with the frequency of the reference peak of TMS | 29 | |
| 5985572300 | Chiral Carbon | A carbon with 4 different groups attached to it | 30 | |
| 5985574255 | Chromatogram | A visible record showing the result of separation of the components of a mixture by chromatography | 31 | |
| 5985578364 | Cis-trans isomerism | A type of E/Z isomerism where each carbon of the C=C double bond carries the same atom or group |  | 32 |
| 5985583185 | Complex ion | A transition metal ion bonded to one or more ligands by dative covalent bonds | 33 | |
| 5985595561 | Condensation polymer | The chemical reaction to form a long chain molecule by elimination of a small molecule e.g. water | 34 | |
| 5985597581 | Conjugate acid-base pair | Two species that transform into each other by the gain or loss of a proton | 35 | |
| 5985599889 | Coordination number | The total number of dative covalent bonds formed between a central metal ion and its ligands | 36 | |
| 5985601396 | Covalent bond | A bond formed by a shared pair of electrons between nuclei | 37 | |
| 5985602886 | Curly arrow | A symbol used in reaction mechanisms to show the movement of an electron pair | 38 | |
| 5985604550 | Dative covalent bond | A bond formed by a shared pair of electrons that has been provided by one of the bonding atoms only (AKA coordinate bond) | 39 | |
| 5985606899 | Degradable polymer | A polymer that breaks down into smaller fragments when exposed to light, heat or moisture | 40 | |
| 5985609085 | Delocalised electrons | Electrons that are shared between more than 2 atoms | 41 | |
| 5985611060 | Deuterium | An isotope of hydrogen and does not produce a signal in proton NMR | 42 | |
| 5985612771 | Directing effect | How a functional group attached directly to an aromatic ring affects which carbon atoms are more likely to undergo substitution | 43 | |
| 5985615033 | Displayed formula | A formula which shows the relative positions of atoms and the bonds between them | 44 | |
| 5985616754 | Disproportionation | The oxidation and reduction of the same element in a redox reaction | 45 | |
| 5985617336 | Distillation | A technique used to separate miscible liquids or solutions | 46 | |
| 5985618793 | 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 chemicals have their concentrations maintained | 47 | |
| 5985621208 | Electron configuration | The arrangement of electrons in an atom or ion | 48 | |
| 5985624812 | Electrophile | An electron pair acceptor | 49 | |
| 5985626796 | 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 a pair of electrons | 50 | |
| 5985631186 | Elimination reaction | An organic chemical reaction in which one reactant forms 2 products, usually a small molecule is released | 51 | |
| 5985633423 | Empirical formula | The simplest whole number ratio of atoms of each element present in a compound | 52 | |
| 5985635139 | Enantiomer | An optical isomer | 53 | |
| 5985635480 | Endothermic | A reaction in which the enthalpy of products is greater than the enthalpy of reactants, so heat is taken in from the surroundings (positive delta H) | 54 | |
| 5985639860 | End point | The point in a titration at which there are equal concentrations of the weak acid and conjugate base forms of the indicator | 55 | |
| 5985641896 | Enthalpy cycle | A diagram showing alternative routes between reactants and products | 56 | |
| 5985644508 | Enthalpy profile diagram | A diagram of a reaction that allows you to compare the enthalpy of the reactants with the enthalpy of the products | 57 | |
| 5985646823 | Enthalpy, H | The heat content that is stored in a chemical system | 58 | |
| 5985648019 | Entropy, S | A measure of disorder in a system | 59 | |
| 5985649161 | Equivalence point | The point in a titration at which the volume of one solution has reacted exactly with the volume of the second solution. This matches the stoichiometry of the reaction taking place | 60 | |
| 5985661898 | Equivalent carbon atoms | Carbon atoms bonded to the same atoms that therefore experience the same magnetic field in the NMR | 61 | |
| 5985667182 | Equivalent protons | Hydrogen atoms bonded to the same atoms that therefore experience the same magnetic field in the NMR | 62 | |
| 5985754472 | Esterification | The chemical reaction which forms an ester | 63 | |
| 5985757057 | Exothermic | A reaction in which the enthalpy of the products is smaller than the enthalpy of the reactants, so heat is lost (negative delta H) | 64 | |
| 5985767082 | E/Z isomerism | A type of stereoisomerism that is caused by the restriction of rotation around the double bond. 2 different groups are attached to each carbon atom of the C=C bond | 65 | |
| 5985775585 | First electron affinity | The enthalpy change when 1 mole of gaseous 1- ions are formed from gaseous atoms | 66 | |
| 5985778298 | First ionization energy | The energy change when 1 mole of electrons is removed from 1 mole of gaseous atoms to from 1 mole of gaseous 1+ ions | 67 | |
| 5985781479 | Free energy change, delta G | Delta G= delta H-T x delta S. The reaction can take place when delta G<0 | 68 | |
| 5985785159 | Friedel Crafts reaction | A substitution reaction where hydrogen is exchanged for an alkyl or alcyl chain. They allow electrophilic substitution to occur on an aromatic ring | 69 | |
| 5985787284 | Functional group | A group of atoms that is responsible for the characteristic chemical reactions of a compound | 70 | |
| 5985788227 | General formula | The simplest algebraic formula for a homologous series | 71 | |
| 5985789545 | Geometric/stereo isomers | Molecules that have the same structural formula but a different arrangement in space | 72 | |
| 5985792165 | Giant ionic lattice | 3D structure of atoms that are all bonded together by strong covalent bonds | 73 | |
| 5985793938 | Giant metallic lattice | 3D structure of positive ions and delocalized electrons, bonded together by strong metallic bonds | 74 | |
| 5985795192 | Half-life | The time taken for the concentration of a reactant to reduce by half | 75 | |
| 5985796485 | Hess' Law | States that the enthalpy change in a chemical reaction is independent of the route it takes | 76 | |
| 5985797962 | Heterogeneous equilibrium | An equilibrium in which species making up the reactants and products are in different physical states | 77 | |
| 5985799593 | Homogenous equilibrium | An equilibrium in which all species making up the reactants and products are the same physical state | 78 | |
| 5985801240 | Homologous series | A series of organic compounds that have the same functional group with successive members differing by CH2 | 79 | |
| 5985804805 | Hydrolysis | A chemical reaction where water is a reactant in a decomposition reaction | 80 | |
| 5985806885 | Intermediate | A species formed in one step of a multi-step reaction that is used up in a subsequent step, and is not seen in the overall equation | 81 | |
| 5985808508 | Ionic bonding | The electrostatic attraction between oppositely charged ions | 82 | |
| 5985810063 | Kw | [H+(aq)][OH-(aq)]. At 25c Kw=1.00x10^-14 | 83 | |
| 5985812166 | Isoelectric point | The pH value at which the amino acid exists as a zwitterion | 84 | |
| 5985813370 | Lattice enthalpy | The enthalpy change when one mole of an ionic lattice is formed from its gaseous ions under standard conditions | 85 | |
| 5985817670 | Le Chatelier's principle | States that when a system in dynamic equilibrium is subjected to change, the position of equilibrium will shift to minimize the change | 86 | |
| 5985819453 | Lewis acid | An electron pair acceptor | 87 | |
| 5985819854 | Ligand | A molecule or ion that can donate a pair of electrons to the transition metal ion to form a coordinate bond | 88 | |
| 5985824476 | Ligand substitution | A reaction in which one ligand in a complex ion is replaced by another ligand | 89 | |
| 5985825332 | Lone pair | An outer shell pair of electrons that is not involved in chemical bonding | 90 | |
| 5985827169 | Mass number | The number of protons and neutrons in a nucleus | 91 | |
| 5985828573 | Mobile phase | The phase that moves in chromatography | 92 | |
| 5985830562 | Moles | n= MxMr | 93 | |
| 5985833197 | Mole fraction | A measure of how much of a given substance is present in a reaction mixture | 94 | |
| 5985844971 | Molecular formula | Shows the numbers and type of the atoms of each element in a compound | 95 | |
| 6012876754 | Molecular ion | The positive ion formed in mass spectrometry when a molecule loses an electron | 96 | |
| 6012878065 | Monomers | Small molecules used to make polymers | 97 | |
| 6012879224 | Neutralisation | A chemical reaction in which an acid and a base react together to produce a salt and water | 98 | |
| 6012880920 | Nitrile | An organic chemical with a -CN group | 99 | |
| 6012881766 | Nucleophile | A species that contains a lone pair of electrons or a negative charge and is attracted to positive areas of a molecule | 100 | |
| 6012884003 | Optical isomers | Molecules that are non-superimposable mirror images of each other. They have the same chemical properties but interact with polarized light differently | 101 | |
| 6012886743 | Order | With respect to a reactant, the order is the power to which the concentration of the reactant is raised in the rate equation | 102 | |
| 6012888825 | Overall order | The sum of the individual orders | 103 | |
| 6012889905 | Oxidation | Loss of electrons, or an increase in oxidation number | 104 | |
| 6012890923 | Oxidation number | A measure of the number of electrons that an atom uses to bond with atoms of another element | 105 | |
| 6012892159 | Oxidising agent | The species that is reduced in a reaction and causes another species to be oxidised | 106 | |
| 6012893953 | Partial pressure | The pressure an individual gaseous substance would exert if it occupied a whole reaction vessel on its own | 107 | |
| 6012895095 | Phase | A physically distinctive form of a substance | 108 | |
| 6012896038 | Phenols | A class of aromatic compounds where a hydroxyl group is directly attached to the aromatic ring | 109 | |
| 6012897327 | pH | -log[H+(aq)] | 110 | |
| 6012898528 | Pi bond | The sideways overlap of adjacent p-orbitals above and below the bonding C atoms | 111 | |
| 6012899550 | Polar molecule | A molecule with an overall dipole, having taken into account any dipoles across bonds | 112 | |
| 6012901731 | Polymer | A macromolecule made from small repeating monomers | 113 | |
| 6012902844 | Precipitation reaction | A formation of a solid from a solution during a chemical reaction | 114 | |
| 6012904414 | Qualitative analysis | An observable change and does not involve observations using numerical values | 115 | |
| 6012905583 | Rate constant, k | The constant that links the rate of reaction with the concentrations of reactants raised to the powers of their orders in the rate equation | 116 | |
| 6012907604 | Rate determining step | The slowest step in the reaction mechanism of a multi-step reaction | 117 | |
| 6012909257 | Rate equation | rate= k[A]^m[B]^n | 118 | |
| 6012910501 | Rate of reaction | The change in concentration of a reactant or product per unit time | 119 | |
| 6012912172 | Reaction mechanism | A series of steps that make up the overall reaction or a model with steps to explain and predict a chemical reaction | 120 | |
| 6012914151 | Recyrstallisation | A method for purifying organic compounds | 121 | |
| 6012914701 | Redox reaction | A reaction in which both reduction and oxidation take place | 122 | |
| 6012916554 | Reducing agent | The species that is oxidized in a reaction and causes another species to be reduced | 123 | |
| 6012917640 | Reduction | Gain of electrons, or a decrease in oxidation number | 124 | |
| 6012927656 | Reflux | A technique to stop reaction mixtures boiling dry | 125 | |
| 6012928755 | Relative molecular mass | The weighted men mass of a molecule of a compound compared with one-twelfth of the mass of an atom of carbon 12 | 126 | |
| 6012931048 | Repeat unit | The arrangement of atoms that occurs many times in a polymer | 127 | |
| 6012931904 | Retention time | The time taken for a component to travel from the inlet to the detector in a gas chromatograph | 128 | |
| 6012933701 | Retro-synthesis | Where the synthetic route is designed by looking at the target molecule and working backwards | 129 | |
| 6012934566 | Rf value | A comparison between how far a component has moved compared to the solvent in TLC | 130 | |
| 6012937062 | Salt | Any chemical compound formed from an acid when an H+ ion from the acid has been replaced by a metal ion or another positive ion, often a metal or ammonium ion, NH4+ | 131 | |
| 6012940765 | Saturated hydrocarbon | A hydrocarbon with single bonds only | 132 | |
| 6012941793 | Second electron affinity | The enthalpy change when 1 mole of gaseous 2- ions forms from 1 mole of gaseous 1- ions | 133 | |
| 6012943042 | Second ionization energy | The energy change when 1 mole of gaseous 2+ ions forms from 1 mole of gaseous 1+ ions | 134 | |
| 6012947483 | Shell | A group of atomic orbitals with the same principal quantum number | 135 | |
| 6012949453 | Skeletal formula | A simplified structural formula drawn by removing hydrogen atoms from alkyl chains |  | 136 |
| 6012951749 | Spectator ions | Ions that are present but that play no part in a chemical reaction | 137 | |
| 6012952526 | Spin-spin coupling | The interaction between spin states of non-equivalent nuclei that results in a group of peaks in an NMR spectrum | 138 | |
| 6012955160 | Standard conditions | 100kPa, 298K | 139 | |
| 6012957013 | Standard electrode potential of a half cell | The e.m.f. of half a cell compared with a standard hydrogen half cell, measured at 298K with solution concentrations of 1 moldm-3 and 100kPa | 140 | |
| 6012960578 | Standard enthalpy change of atomisation | The enthalpy change when 1 mole of gaseous atoms is formed from its element in its standard state | 141 | |
| 6012962622 | Standard enthalpy change of formation | The enthalpy change when 1 mole of a compound is formed from it elements | 142 | |
| 6012964746 | Standard enthalpy change of hydration | The enthalpy change when 1 mole of gaseous ions is dissolved in water | 143 | |
| 6012966309 | Standard enthalpy change of solution | The enthalpy change when one mole of a solute is completely dissolved in water under standard conditions | 144 | |
| 6012967768 | Standard entropy | The entropy content of one mole of a substance under standard conditions | 145 | |
| 6012969149 | Standard entropy change of reaction | The entropy change when a reaction in the molar quantities expressed in a chemical equation happens under standard conditions, with all reactants and products being in their standard states | 146 | |
| 6012973020 | Stationary phase | The phase that does not move in chromatography | 147 | |
| 6012976176 | Stereoisomers | Species with the same structural formula but with a different arrangement of atoms in space | 148 | |
| 6012977175 | Stoichiometry | The molar relationship between the relative quantities of substances taking part in a reaction | 149 | |
| 6012982358 | Strong acid | An acid that completely dissociates in solution | 150 | |
| 6012985211 | Structural isomers | Compounds with the same molecular formula but different structural formula | 151 | |
| 6012986874 | Sub-shell | A group of the same type of atomic orbitals within a shell | 152 | |
| 6012988453 | Substitution reaction | When an atom or group of atoms is replaced by a different atom or group of atoms | 153 | |
| 6012990233 | Synthetic route | A series of reactions that can be used to change a starting chemical into a target molecule | 154 | |
| 6012992318 | TMS | An internal standard for both carbon and proton NMR | 155 | |
| 6013000387 | Transition metal | A d-block element that has an incomplete d-sub shell as a stable ion | 156 | |
| 6013002723 | Unsaturated hydrocarbon | A hydrocarbon containing multiple carbon carbon double bonds | 157 | |
| 6013004536 | Van der Waals force | Intermolecular bonding that includes permanent dipole-dipole bonding and induced dipole-dipole interactions | 158 | |
| 6013007700 | Water of Crystallisation | Water molecules that form an essential part of the crystalline structure of a compound | 159 | |
| 6013009211 | Weak acid | An acid that partially dissociates in solution | 160 | |
| 6013010229 | Zwitterion | An internal salt, with no charge, formed by the donation of a proton from a carboxylic acid group to an amine group in an amino acid | 161 |
