Chemistry key words

A species that releases H ions in solution
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Acid dissociation constant, Ka
eqm constant that shows the extent of dissociation of a WEAK ACID= [H+][A-]/[HA]
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Acid-base pair
A pair of species that can transform into one another by the loss or gain of a proton
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Activation energy
The minimum energy required to start a reaction by the breaking of bonds
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Actual yield
The amount of product obtained from a reaction
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Addition polymerisation
formation of a very long molecular chain, by repeated addition reactions of monomers
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Addition reaction
REaction in which a reactant is added to an unsaturated molecule to make a saturated molecule
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process that occurs when a gas or liquid or solute is held to the surface of a solid
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containing C atoms joined together in a non-aromatic ring
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containing C atoms joined together in straight or unbranched chains
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Type of base that dissolves in water forming OH- ions
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Hydrocarbon homologous series with single C-C bonds and general formula CnH2n
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Alkyl group
Side chain formed by removing a H atom from an alkane parent chain
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Hydrocarbon homologous series with one triple c-c bond and the general formula CnH2n-2
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Amount of substance
The quantity whose unit of mole is a means of counting species such as atoms, ions and molecules
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Containing no water molecules
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negatively charged ion (more electrons that protons)
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Containing one or more benzene rings
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Atom economy
sum of molar masses desired/sum molar masses all products X 100
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Atomic/proton number
Number of protons in the nucleus of an atom
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Atomic orbital
A region around the nucleus that can hold up to two electrons, with opposite spins
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Average bond enthalpy
the average enthalpy change that takes place when breaking by homolytic bond fission 1 mol of a given type of bond in the molecules of a gaseous species
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Avogadro constant
Number of atoms per mole of the C-12 isotope
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a compound that neutralises an acid to form a salt
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Binary compound
compound containing 2 elements only
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Bond angle
angle between two bonds at an atom
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Bond dissociation enthalpy
Enthalpy change that takes place by homolytic fission 1 mol of a given bond in the molecules of a gaseous species
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Bonded pair
A pair of electrons shared between 2 atoms to make a covalent bond
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Bronsted-Lowry Acid
A species that is a proton donor
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Bronsted-Lowry Base
A species that is a proton acceptor
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Buffer solution
A system that minimises changes in pH on addition of small amounts of an acid or base
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A positively charged Carbon atom
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Substance that increases the rate of a chemical reaction without being used up in the process- providing an alternative route for the reaction with a lower activation energy
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positively charged ion
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Chain reaction
reaction in which the propagation release new radicals that continue the reaction
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Chemical shift
A scale that compares the frequency of an NMR absorption with the frequency of the reference TMS at 0 ppm
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Chiral carbon
a carbon with 4 different groups attached to it
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visible record showing the result of separation of the components of a mixture by chromatography
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Cis-trans isomerism
special type of E/Z isomerism which there are 2 non-hydrogen groups and 2 hydrogen atoms around the c-c double bond. Cis= Z Trans= E
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Closed system
system isolated from its surroundings
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Collision theory
2 reacting particles must collide for a reaction to occur, must be in the correct orientation and have enough energy to overcome the Ea of the reaction
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Complex ion
transition metal ion bonded to ligands by co-ordinate bonds
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amount of solute in moles dissolved in 1dm3 of solution
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Condensation reaction
Reaction in which 2 small molecules form a larger molecule with elimination of water
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Conjugate acid
species that releases a proton to form a conjugate base
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Conjugate base
species that accepts a proton to form a conjugate acid
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Co-ordinate/ dative covalent bond
shared paid of electrons in which bonded pair has been provided by one of the bonding atoms only
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Co-ordination number
the total number of co-ordinate bonds formed between a central metal ion and ligands
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Covalent bond
Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
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Dative covalent
shared pair of electrons in which bonded pair has been provided by one of the bonding atoms only
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Elimination reaction in which water is removed to from a saturated molecule to form an unsaturated molecule
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Delocalised electrons
Electrons that are shared between more than two atoms
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Release of an adsorped substance from a surface
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One atom of a polar covalent bond has a small positive charge whilst the other has a small negative charge
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Displacement reaction
A reaction in which a more reactive element displaces a less reactive element from an aq solution of its ions
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Displayed formula
formula showing the relative positioning of all the atoms in a molecule and the bonds between them
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A redox reaction in which same element is both oxidised and reduced
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Dynamic eqm
the eqm that exists in a closed system when rate of forward reaction= rate of backwards reaction and concentrations do not change
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E/Z isomerism
type of isomerism in which different groups attatched to each carbon of souble bond may be arranged differently in space because of the restricted rotation of double bonds
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Electron configuration
shows how many electrons occupy sub-shells in an atom
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measure of the attraction of a bonded atom for the pair of electrons in a covalent bond
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An atom/group of atoms attracted to an electron-rich centre where they accept a pair of electrons
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Electrophillic addition
addition reaction in which first step is attack by electrophile in a region of high electron density
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Electrophillic substition
type of substitution in which an electrophile is attracted to electron-rich centre and accepts a pair of electrons
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Elimination reaction
removal of a molecule from a saturated molecule to make an unsaturated molecule
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Empirical formula
formula that shows the simplest whole-number ratio of atoms of each element present in a compound
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Enantiomers/ Optical isomers
stereoisomers that are non-superimposable mirror images of eachother
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End point
point in a titration where the inidcator changes colour & indicates the reaction is complete
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Endothermic reaction
reaction in which the enthalpy of the products is greater than the enthalpy of reactants resulting in heat being taken in from surroundings
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heat content that is stored in a chemical system
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Enthalpy change
the difference between the enthalpy of the products and the enthalpy of reactants
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Enthalpy cycle
diagram showing alternative routes between reactants and products which allows the indirect determination of an enthalpy change from other known enthalpy changes using Hess' law
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Enthalpy profile diagram
diagram for a rection to compare the enthalpy of the reactants with the enthalpy of the products
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the dispersal of energy and disorder within the chemicals making up the chemical system
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Equilibrium constant Kc
measure of the position of eqm
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Equivalence point
point in a titration at which the volume of one solution has reacted exactly with the volume of the second solution
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Reaction in which carboxylic acid reacts with an alcohol to form an ester
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Exothermic reaction
enthalpy of products smaller than enthalpy of reactants= heat loss to surroundings
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Fingerprint region
area of IR spectrabelow 1500cm-1 that gives a characteristic pattern for different compounds
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First electron affinity
enthalp change that takes place when one electron is added to each atom in one mole of gaseous atoms to forms one mole of negative ions
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First ionisation energy
energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous cations
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Fractional distillation
separation of components in a liquid mixture by their different boiling points into fractions with different compositions
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Fragment ions
ions formed from the breakdown of the molecular ion in a mass spectrometer
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process in mass spec that causes a cation to split into smaller pieces
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Free energy change (delta G)
balance between the enthalpy, entropy and temperature for a process- fesible when G
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Functional group
part of the organic molecule responsible for its chemical reactions
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General formula
simplest algebraic formula of a member of a homologous series
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Giant covalent lattice
3-D structure of atoms, bonded together by strong covalent bonds
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Giant ionic lattice
3-D structure of oppositely charged ions, held together by strong ionic bonds
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Giant metallic lattice
3-D structure of positive metal ions and a sea of delocalised electrons, held together by strong metallic bonds
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Vertical column in periodic table (elements have similar chemical properties)
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time taken for conc. of a reactant to decrease by half
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Hess' law
if a reaction can take place by more than one route and the initial and final conditions are the same, the total enthalpy change is the same for each route
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Heterogenous catalysis
reaction in which catalysts has different physical state from reactants, frequently reactants are gases whilst catalyst is solid
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Heterolytic fission
breaking of a covalent bond with both of the electrons going to one bonded atom, forming ions
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Homogeneous catalysis
reaction in which catalysts and reactants are in the same physical state- usually aq or gas
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Homogenoues eqm
eqm in which all species making up reactants & products have same physical state
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Homologous series
series of organic ompounds w/ same functional group but with each successive member differing by CH2
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Homolytic fission
breaking of a convalent bond with one of bonded electrongs going to each atoms to form radicals
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a crystalline compound containing water molecules
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compound containing hydrogen and carbon only
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Hydrogen bond
strong dipole dipole interaction between the electron defficient hygrogen of one atom and the one pair of electron from O,N,F
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Reaction with water that breaks a chemical compound into two compounds
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Induced dipole-dipole interactions/ London forces
attractive forces between induced dipoles in different molecules
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Infrared spectroscopy
Instrumentation method of analysis that identifies bonds from absorption of the infrared radiation of different wavelengths
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Initial rate of reaction
Change in conc. of a reactant or product per unit time at the start of the reaction (t=0)
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first stage in radical reaction in which radical starts when a covalent bond is broken by homolytic fission of a covalent bond
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species formed during a reaction that reacts further and is not present in the final products
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Intermolecular force
an attractive force between molecules- can be london forces, permanent dipole-dipole interactions or hydrogen bonding
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charged atom where number of electrons is different from number of protons
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Ionic bonding
electrostatic attraction between positive and negative ions
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Ionic product of water- Kw
the product of the ions formed in the partial dissociation of water kw= [H+][OH-]
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atoms of same element with different numbers of neutrons and different masses
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Lattice enthalpy
enthalpy change of formation of one mole of an ionic compound from its gaseous ions under standard condtions
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Le Chatelier'sprinciple
when a system in dynamic eqm is subjected to an external change- system readjusts to minimise the effects of the change
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molecule/ion that can donate a pair of electrons to the transition metal ion
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Ligand substitution
Reaction in which one or more ligands in a complex ion are replaced by different ligands
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Limiting reagant
reactant that is not in excess which will be used up first and stop the reaction
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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
sum of protons and neutrons in the nucleus
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Metallic bond
the electrostatic attraction between positive metal ions and delocalised electrons
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Mobile phase
the phase that moves in chromatography
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Molar gas volume
volume/mole of gas molecules at a stated temperature and pressure
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Molar mass
the mass per mole of a substance in gmol-1
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amount of any substance containing as many particles as there are C atoms in exactly 12g of C-12 isotope (6.022x10^23)
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Molecular formula
formula that shows the number and type of atoms of each element present in a molecule
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Molecular ion
positive ion formed in mass spec when a molecule loses an electron
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a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
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a small molecule that combines with many other monomers to form a polymer
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chemical reaction in which an acid and a base react together to produce a salt
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system of naming compounds
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no charge separation across a bond or in a molecule
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electron pair donor (attracted to electron deficient atom)
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Nucleophilic substitution
reaction in which a nucleophile is attracted to an electron defficient C atom and replaces an atom or group of atoms on the carbon atom
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Optical isomers
Stereoisomers that are non-superimposable mirror images
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power to which reactants are raised in the rate equation
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Overall order
sum of orders of the reaction
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the loss of electrons
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Oxidation number
measure of the number of electrons that an atom uses to bond with atoms of another element
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Oxidising agent
reagent that oxidises another species and becomes reduced
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bond formed by sideways overlap of 2 p-orbitals= electron density above and below the plane of the bonding atoms
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Partial dissociation
Only some of the species is split in solution of aq ions
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Pauling electronegativity value
Value assigned as a measure of the relative attraction of a bonded atom from the pair of electrons in a covalent bond
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Horizontal row on periodic table
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repeating trend in properties of elements across each period
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Permanent dipole
These occur when two atoms in a molecule have substantially different electronegativity: One atom attracts electrons more than another, becoming more negative, while the other atom becomes more positive= polar
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Polar covalent bond
bond with a permanent dipole
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Polar molecule
molecule with an overall dipole having taken into account the shape of the molecule and symmetry
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Polyatomic ion
ion containing more than one ion
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large molecule formed from repeating monomer units
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Precipitation reaction
formation of a solid from a solution during a chemical reaction
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Principal quantum number
number representing relative overall energy of each orbital, increases with distance from nucleus
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steps that continue a free radical reaction, radical reacts with reactant to form a new molecule & another radical= chain reaction
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species with an unpaird electron
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Rate constant, k
constant that links the rate of reaction with the concentration of reactants
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Rate of reaction
change in concentration of a reactant/product over a given time
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Rate-determining step
slowest step in the reaction mechanism of a multi-step reaction
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Redox reaction
reaction involving reduction and oxidation
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Reducing agent
reduces another species and becomes oxidised
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Gain of electrons
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continual boiling and condensing of a reaction mixture
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relative atomic mass
the weighted mean mass of an atom of an element compared to 1/12 of the mass of an atom of C-12
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Relative formula mass
weighted mean mass of the formula unit of a compound compared with 1/12 of the mass of an atom of C-12
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Relative isotopic mass
The mass of an atom of an isotope compared with 1/12 of the mass of an atom of C-12
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Relative molecular mass
weighted mean mass of a molecule of a compound compared to 1/12 of the mass of an atom of C-12
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Retention time
time for a component to pass from the column inlet to the detector
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formed by overalp of one orbital from each bonding atom directly between the nuclei of 2 atoms
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containing single bonds only
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a group of atomic orbitals with the same energy level
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Shielding effect
repulsion between electrons in different inner shells- reduces net attractive force between the positive nucleus and outer shell electrons
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Simple molecular lattice
3-D structure of molecules, bonded together by weak IMF
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Skeletal formula
simplified organic formula leaving just carbon skeletal and functional groups
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Spectator ions
Ions that are present but dont take part in chemical reactions
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Spin-spin coupling
in NMR spec= the interaction between spin states of non-equivalent nuclei leading to splitting
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Standard conditions
Pressure=100kPa temp= 298K conc= 1 mol dm-3
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Standard electrode potential
the EMF of a half-cell compared with a standard hydrogen hald-cell under standard conditions
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Standard enthalpy change of atomisation
enthalpy change that takes place when one mole of gaseous atoms forms from the element in its standard state
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Standard enthalpy change of combustion
enthalpy change when one mole of a substance reacts completely with oxygen under standard conditions, all reactants and products being in their standard states
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Standard enthalpy change of formation
enthalpy change that takes places when one mole of a compound is formed from its constituent elements in their standard states under standard conditions
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Standard enthalpy change of hydration
enthalpy change when one mole of isolated gaseous ions is dissolved in water forming one mole of aqueous ions under standard conditions
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Standard enthalpy change of neutralisation
enthalpy change that accompanies the reaction of an acid by a base to form one mole of water, under standard conditions with all reactants and products in their standard states
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Standard enthalpy change of reaction
enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions, with all reactants and products in their standard states
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Standard enthalpy change of solution
enthalpy change when one mole of a compound is completely dissolved in water under standard conditions
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Standard solution
solution of known conc.
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Standard state
the physical state of a substance under standard conditions
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Stationary phase
phase that does not move in chromatography
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compounds with the same structural formula but with a different arrangement of atoms in space
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ratio of the amount, in moles of each substance in a chemical equation
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Strong acid
acid that dissociates completely in solution
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Structural formula
Formula showing the minimal detail for the arrangement of atoms in a molecule
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Structural isomers
molecules with the same molecular formula but different structural formula
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group of orbitals of the same type within a shell
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Substitution reaction
reaction in which an atom or group of atoms is replaced with a different atom or group of atoms
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the chemicals involved in the reaction
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step at the end of a radical substitution when two radicals combine to form a new molecule
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Theoretical yield
yield resulting from complete conversion of reactants to products
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Thermal decomposition
breaking up of a chemical substance with heat into at least two chemical substances
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vol. added from the burette when the volume of one solution has exactly reacted with the other solution
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Transition element
d-block element which forms an ion with an incomplete d sub-shell
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containing carbon-carbon multiple bonds
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ease at which a liquid turns into a gas- volatility increases as bpt decreases
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Water of crystallisation
Water molecules that are bonded into a crystalline structure of compound
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Weak acid
acid that only partially dissociates in solution
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Other cards in this set

Card 2


Acid dissociation constant, Ka


eqm constant that shows the extent of dissociation of a WEAK ACID= [H+][A-]/[HA]

Card 3


Acid-base pair


Preview of the front of card 3

Card 4


Activation energy


Preview of the front of card 4

Card 5


Actual yield


Preview of the front of card 5
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