The minimum energy required to start a reaction by breaking bonds in the reactants
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Addition Polymer
A very long molecular chain formed by repeated addition reactions of many unsaturated alkene molecules
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Addition Reaction
A reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule
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Acid Dissociation Constant
Ka\= [H+(aq)][A-(aq)]/[HA(aq)]
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Aliphatic Hydrocarbon
A hydrocarbon where carbon atoms are joined together in straight or branched chains
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Alkali
A base that dissolves in water forming OH- ions
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Alkanes
The homologous series with general formula CnH2n+2
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Alkylammonium salt
A compound where the hydrogen's on an ammonium ion have been substituted by alkyl chains
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Alkylation
Addition of hydrocarbon chains to an organic compound
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Alkyl group
An alkane with a hydrogen atom removed e.g. CH3, C2H5
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Amide
A compound with a functional group made of an alcyl group, which is directly attached to an amine
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Amphoteric chemicals
Chemicals that can react with both acids and bases
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Anion
A negatively charged ion
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Anhydrous
A substance that contains no water molecules
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Arrhenius plot
A graph of lnK \= lnA - Ea/R x 1/T
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Atomic Orbital
A region of space where you will likely find electrons. Each orbital can hold 2 electrons, with opposite spins
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Atomic number
The number of protons in the nucleus of an atom
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Average bond enthalpy
The mean energy needed for 1 mole of a given type of gaseous bonds to undergo homolytic fission
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Avogadro constant
The number of atoms per mole of the carbon-12 isotope (6.02x10^23)
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Base
A chemical that will react with an acid
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Benzene
A naturally occurring aromatic compound, which is very stable planar ring structure with delocalized electrons
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Benzene Derivative
A benzene ring that has undergone a substitution reaction
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Boltzman Distribution
The distribution of energies of molecules at a particular temperature
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Bronsted-Lowry acid
A proton donor
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Bronsted- Lowry base
A proton acceptor
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Buffer solution
A mixture that minimizes pH changes on addition of small amounts of acid or base
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Carbocation
An organic ion in which a carbon atom has a positive charge
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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
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Cation
A positively charged ion
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Chemical Shift
The scale that compares the frequency of NMR absorption with the frequency of the reference peak of TMS
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Chiral Carbon
A carbon with 4 different groups attached to it
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Chromatogram
A visible record showing the result of separation of the components of a mixture by chromatography
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Cis-trans isomerism
A type of E/Z isomerism where each carbon of the C\=C double bond carries the same atom or group
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Complex ion
A transition metal ion bonded to one or more ligands by dative covalent bonds
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Condensation polymer
The chemical reaction to form a long chain molecule by elimination of a small molecule e.g. water
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Conjugate acid-base pair
Two species that transform into each other by the gain or loss of a proton
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Coordination number
The total number of dative covalent bonds formed between a central metal ion and its ligands
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Covalent bond
A bond formed by a shared pair of electrons between nuclei
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Curly arrow
A symbol used in reaction mechanisms to show the movement of an electron pair
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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)
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Degradable polymer
A polymer that breaks down into smaller fragments when exposed to light, heat or moisture
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Delocalised electrons
Electrons that are shared between more than 2 atoms
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Deuterium
An isotope of hydrogen and does not produce a signal in proton NMR
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Directing effect
How a functional group attached directly to an aromatic ring affects which carbon atoms are more likely to undergo substitution
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Displayed formula
A formula which shows the relative positions of atoms and the bonds between them
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Disproportionation
The oxidation and reduction of the same element in a redox reaction
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Distillation
A technique used to separate miscible liquids or solutions
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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
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Electron configuration
The arrangement of electrons in an atom or ion
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Electrophile
An electron pair acceptor
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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
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Elimination reaction
An organic chemical reaction in which one reactant forms 2 products, usually a small molecule is released
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Empirical formula
The simplest whole number ratio of atoms of each element present in a compound
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Enantiomer
An optical isomer
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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)
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End point
The point in a titration at which there are equal concentrations of the weak acid and conjugate base forms of the indicator
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Enthalpy cycle
A diagram showing alternative routes between reactants and products
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Enthalpy profile diagram
A diagram of a reaction that allows you to compare the enthalpy of the reactants with the enthalpy of the products
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Enthalpy, H
The heat content that is stored in a chemical system
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Entropy, S
A measure of disorder in a system
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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
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Equivalent carbon atoms
Carbon atoms bonded to the same atoms that therefore experience the same magnetic field in the NMR
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Equivalent protons
Hydrogen atoms bonded to the same atoms that therefore experience the same magnetic field in the NMR
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Esterification
The chemical reaction which forms an ester
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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)
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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
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First electron affinity
The enthalpy change when 1 mole of gaseous 1- ions are formed from gaseous atoms
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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
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Free energy change, delta G
Delta G\= delta H-T x delta S. The reaction can take place when delta G
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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
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Functional group
A group of atoms that is responsible for the characteristic chemical reactions of a compound
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General formula
The simplest algebraic formula for a homologous series
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Geometric/stereo isomers
Molecules that have the same structural formula but a different arrangement in space
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Giant ionic lattice
3D structure of atoms that are all bonded together by strong covalent bonds
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Giant metallic lattice
3D structure of positive ions and delocalized electrons, bonded together by strong metallic bonds
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Half-life
The time taken for the concentration of a reactant to reduce by half
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Hess' Law
States that the enthalpy change in a chemical reaction is independent of the route it takes
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Heterogeneous equilibrium
An equilibrium in which species making up the reactants and products are in different physical states
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Homogenous equilibrium
An equilibrium in which all species making up the reactants and products are the same physical state
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Homologous series
A series of organic compounds that have the same functional group with successive members differing by CH2
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Hydrolysis
A chemical reaction where water is a reactant in a decomposition reaction
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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
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Ionic bonding
The electrostatic attraction between oppositely charged ions
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Kw
\[H+(aq)][OH-(aq)]. At 25c Kw\=1.00x10^-14
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Isoelectric point
The pH value at which the amino acid exists as a zwitterion
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Lattice enthalpy
The enthalpy change when one mole of an ionic lattice is formed from its gaseous ions under standard conditions
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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
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Lewis acid
An electron pair acceptor
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Ligand
A molecule or ion that can donate a pair of electrons to the transition metal ion to form a coordinate bond
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Ligand substitution
A reaction in which one ligand in a complex ion is replaced by another ligand
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Lone pair
An outer shell pair of electrons that is not involved in chemical bonding
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Mass number
The number of protons and neutrons in a nucleus
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Mobile phase
The phase that moves in chromatography
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Moles
n\= MxMr
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Mole fraction
A measure of how much of a given substance is present in a reaction mixture
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Molecular formula
Shows the numbers and type of the atoms of each element in a compound
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Molecular ion
The positive ion formed in mass spectrometry when a molecule loses an electron
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Monomers
Small molecules used to make polymers
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Neutralisation
A chemical reaction in which an acid and a base react together to produce a salt and water
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Flashcard (117)