Organic definitions Flashcards
Define addition polymerisation
Formation of a very long molecular chain, by repeated addition reactions of many unsaturated alkene molecules
Define addition reaction
A reaction in which a reactant is added to an unsaturated molecule to make one saturated molecule
Define alicyclic
Containing carbon atoms joined together in a non aromatic ring
Define actual yield
The amount of product obtained in a reaction
Define aliphatic
Containing carbon atoms joined together in straight or branched chains
Define alkanes
The hydrocarbon homologous series with single carbon-carbon bonds only and the general formula CnH2n+2
Define acid
A species that releases H+ ions in aqueous solution
Define alkali
A type of base that dissolves in water forming hydroxide ions OH- (aq)
Define alkenes
The hydrocarbon homologous series with at least one double carbon-carbon bond and the general formula CnH2n
Define alkynes
The hydrocarbon homologous series with one triple carbon-carbon bond and the general formula CnH2n-2
Define amount of substance
The quantity whose unit of the mole, used as a means of counting any species such as atoms, ions and molecules
Define anhydrous
Containing no water molecules
Define anion
A negatively charged ion with more electrons than protons
Define aromatic
Containing one or more benzene rings
Define atom economy
Atom economy= (Sum of molar masses of desired products)/ (Sum of molar masses of all products) *100
Define atomic number
The number of protons in the nucleus of an atom
Define atomic orbital
A region around the nucleus that can hold up to two electrons with opposite spins
Define Avogadro constant
The number of atoms per mole of the carbon-12 isotope
Define base
Bases are protons acceptors, they neutralise an acid to form a salt
Define a binary compound
A compound containing two elements only
Define bonded pair
A pair of electrons shared between two atoms to make a covalent bond
Define carbocation
An ion that contains a positively charged carbon atom.
An intermediate in electrophilic addition
Define cation
A postively charged ion with fewer electrons than protons
Define chain reaction
A reaction in which the propagation steps release new radicals that continue the reaction
Define chemical shift
A scale, in ppm, that compares the frequency of an NMR absorption with the frequency of the reference TMS
Define chiral carbon
A carbon atom attached to four different atoms or groups of atoms
Define chromatogram
A visible record showing the result of separation of the components of a mixture by chromatography
Define Cis-trans isomerism
A special case of E/Z isomerism in which 1 of the two groups attained to each carbon of the double bond is the same.
If the same group on the same side of double bond-cis
otherwise-trans
Define concentration
The amount of solute, in moles, dissolved in 1dm3 of solution
Define condensation reaction
A reaction in which two small molecules react together to form a larger molecule with elimination of a small molecule such as water
Define coordinate bond
A shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only, also called a dative covalent bond
Define covalent bond
The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
Define dative covalent
A shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only, also called a coordinate bond
Define dehydration
An elimination reaction in which water is removed from a saturated molecule to make an unsaturated one
Define delocalised electrons
Electrons that are shared between more than two atoms
Define dipole
A separation in electrical charge so that one atom of a polar covalent bond, or one end of a polar molecule has a small positive charge and the other has a small negative charge
Define displayed formula
A formula showing the relative positioning of all the atoms in a molecule and the bonds between them
Define disproportionation
A redox reaction in which the same element is both oxidised and reduced
Define 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 in space because of the restricted rotation of the C=C bond
Define electronegativity
A measure of the attraction of a bonded atom for the pair of shared electrons in a covalent bond
Define electrophile
An atom or group of atoms which is attracted to an electron-rich centre or atom, where it accepts a pair of electrons to form a new covalent bond
Define electrophilic addition
An addition reaction in which the first step is attack by an electrophile on a region of high electron density
Define elimination reaction
The removal of a molecule from a saturated molecule to make an unsaturated molecule
Define enantiomers
Stereoisomers that are non-superimposable mirror images of each other; also called optical isomers
Define esterification
A reaction in which a carboxylic acid reacts with an alcohol to form an ester and water
Define fingerprint region
An area of infrared spectrum below 1500cm-1 that gives a characteristic pattern for different compounds.
Very difficult to interpret
Define fragment ions
Ions formed from the breakdown of the molecular ion in a mass spectrometer
Define fragmentation
The process in mass spectrometry that causes a positive ion to split into smaller pieces, one of which is a positive fragment ion
Define functional group
The part of an organic molecule responsible for its chemical reaction
Define general formula
The simplest algebraic formula of a member of a homologous series
Define giant covalent lattice
A 3d structure of atoms, bonded together by strong covalent bonds
Define giant ionic lattice
A 3d structure of oppositely charged ions bonded together by strong ionic bonds
Define giant metallic lattice
A 3d structure of of positive ions bonded together by strong metallic bonds
Define heterolytic fission
The breaking of a covalent bond forming a cation and an anion. All the shared electrons go to the same atom
Define homologous series
A series of organic compounds with the same functional group but with each successive member differing by CH2
Define homolytic fission
The breaking of a covalent bond with one of the bonded electrons going to each atom, forming two radicals
Define hydrated
A crystalline compound containing water molecules
Define hydrocarbon
A compound of hydrogen and carbon only
Define hydrogen bond
A strong dipole-dipole attraction between an electron-deficient hydrogen atom of -NH, -OH, -HF on one molecule and a lone pair of electrons on a highly electronegative atom containing N,O or F on a different molecule.
Define hydrolysis
A reaction with water that breaks a chemical compound into two compounds, the H and OH in a water molecule becomes incorporated into the two compounds
Define induced dipole-dipole interaction
Attractive forces between induced dipoles in different molecules- London forces
Define infrared spectroscopy
An instrumentation method of analysis that identifies bonds from absorption of the infrared radiation of different wavelengths
Define intermediate
A species formed during a reaction that reacts further and is not present in the final products
Define intermolecular force
An attractive force between molecules. Intermolecular forces can be London forces, permanent dipole-dipole interactions or hydrogen bonding
Define ionic bonding
The electrostatic attraction between positive and negative ions
Define isotopes
Atoms of the same element with different numbers of neutrons and different masses but the same number of protons.
Define limiting reagent
The reactant that is not in excess, which will be used up first and stop the reaction
Define lone pair
An outer shell pair of electrons that is not involved in chemical bonding
Define metallic bond
The electrostatic attraction between positive metal ions and delocalised electrons
Define mobile phase
The phase that moves in chromatography
Define molar gas volume
The volume per mole of gas molecules at a stated temperature and pressure
Define molar mass
The mass per mole of a substance in units g mol-1
Define mole
The amount of any substance containing as many elementary particles as there are carbon atoms in exactly 12g of the carbon-12 isotope that is, 6.02*10^23 particles
Define molecular ion
The positive ion formed in mass spectrometry when a molecule loses an electron
Define monomer
A small molecule that combines with many other monomers to form a polymer
Define neutralisation
A chemical reaction in which an acid and a base react together to produce a salt
Define nucleophile
An atom (or group of atoms) which is attracted to an electron deficient centre or atom, where it donates a pair of electrons in form a new covalent bond
Define nucleophilic substitution
A reaction in which a nucleophile is attracted to an electron deficient carbon atom and replaces an atom or group of atoms on the carbon atom
Define optical isomers
Stereoisomers that are non-superimposable mirror images of each other; also called enantiomers
Define oxidation
Loss of electrons or an increase in oxidation number
Define oxidation number
A measure of the number of electrons that an atom uses to bond with atoms of another element.
Define oxidising agent
A reagent that oxidises another species
Define pi-bond
A bond formed by the sideways overlap of two p-orbitals, with the electron density above and below the plane of the bonding atoms
Define percentage yield
percentage yield= (amount in mol, of a product)/ (theoretical amount, in mol, of product) *100
Define permanent dipole
A small charge difference that does not change across a bond, with delta postive and delta negative partial charges on the bonded atoms: the result of the bonded atoms having different electronegativities
Define permanant dipole-dipole interactions
An attractive force between permanent dipoles in neighbouring polar molecules
Define polar molecule
A molecule that has an overall dipole taking into account all dipoles across bonds and the shape of molecules.
Define polymer
A large molecule formed from many thousands of repeat units of smaller molecules known as monomers
Define radical
A species with an unpaired electron
Define reaction mechanism
The sequence of bond breaking and bond-forming steps that shows the path taken by electrons during a reaction
Define reducing agent
A reagent that reduces another species
Define reduction
Gain of electrons of a decrease in oxidation number
Define reflux
The continual boiling and condensing of a reaction mixture back to the original container to ensure that the reaction takes place without the contents of the flask boiling dry
Define relative atomic mass
The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon-12
Define relative formula mass
The weighted mean mass of the formula unit of a compound compared with 1/12 of the mass of an atom of carbon-12
Define relative isotopic mass
The mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12
Define 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
Define retention time
In gas chromatography, the time taken for a component to pass from the column inlet to the detector
Define repeat unit
The specific arrangement of atoms that occurs in the structure over and over again
Define Rf value
Rf= distance moved by component/ distance moved by solvent
Define sigma-bond
A bond formed by the end on overlap of one orbital from each bonding atom, consisting of two electrons and with the electron density centred around a line directly between the nuclei of the two atoms.
Define salt
The product of a reaction in which the H+ ions from the acid are replaced by metal or ammonium ions
Define saturated
Containing single bonds only
Define shell
A group of atomic orbitals with the same main energy level
Define skeletal formula
A simplified organic formula, with hydrogen atoms removed from alkyl chains leaving just a carbon skeleton and associated functional groups
Define spin-spin coupling
In an NMR spectrum, the interaction between spin states in non-equivalent nuclei result in the splitting of a signal
Define standard conditions
A pressure of 100 kPa
Temperature 298 K or 25 degrees
Concentration of 1 mol dm-3
Define standard solution
A solution of known concentration
Define stationary phase
The phase that does not move in chromatography
Define stereoisomers
Compounds with the same structural formula but with a different arrangement of the atoms in space
Define strong acid
An acid that completely dissociated in solution
Define structural formula
A formula showing the minimal detail for the arrangement of atoms in molecule
Define structural isomers
Molecules with the same molecular formula but with different structural formula
Define sub-shell
A group of orbitals of the same type within a shell
Define theoretical yield
The yield resulting from complete conversion of reactants into products
Define unsaturated
Containing a multiple carbon-carbon bond
Define volatility
The ease at which a liquid turns into a gas. Volatility increases as boiling point decreases
Define water of crystallisation
Water molecules that are bonded into a crystalline structure of a compound
Define weak acid
An acid that dissociated only partially in solution
