4.1 definitions Flashcards
alicyclic
an aliphatic compound that is arranged in non-aromatic rings (with or without side chains).
aliphatic
a compound containing carbon and hydrogen atoms joined in straight or branched chains or in non-aromatic rings.
alkane
a homologous series with the general formula CnH2n+2
alkyl
a group with the general formula CnH2n+1
aromatic
an organic compound containing a benzene ring.
curly arrow
shows the movement of a pair of electrons. Curly arrows must start from a bond, a lone pair of electrons or a negative change.
dipole
a partial charge on an atom which is caused by the differing electronegativities of atoms in a covalent bond.
displayed formula
the relative positions of atoms and the bonds between them.
empirical formula
the simplest whole number ratio of atoms of each element present in a compound.
functional group
group of atoms responsible for the characteristic reactions of a compound,
general formula
the simplest algebraic formula of a member of a homologous series.
general formula
the simplest algebraic formula of a member of a homologous series.
heterolytic fission
when a covalent bond breaks, one bonding atom receives both electrons from the bonded pair.
homologous series
a series of organic compounds containing the same functional group with successive members differing by -CH2
homolytic fission
when a covalent bond breaks, each bonding atom receives one electron from the bonding pair, forming 2 radicals.
IUPAC
International Union of Pure and Applied Chemistry.
IUPAC
International Union of Pure and Applied Chemistry.
molecular formula
the number and type of atoms of each element in a molecule.
nomenclature
the naming systems for compounds
organic compound
a carbon-containing compound
radical
a species with an unpaired electron
reaction mechanism
series of steps that represent the overall reaction by showing the breaking and forming of bonds using curly arrows.
saturated
an organic compound which only contains C-C single bonds.
skeletal formula
the simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving the carbon skeleton and the functional groups.
structural formula
the minimal detail that shows the arrangement of atoms in a molecule.
structural isomers
compounds with the same molecular formula but different structural formulae.
unsaturated
an organic compound which contains at least one C=C double bond, a C=C triple bond or an aromatic ring.
sigma bond
a type of covalent bond which forms when atomic orbitals overlap head-on. Sigma bonds can rotate freely.
alkane
a homologous series with the general formula CnH2n+2
boiling point
the temperature at which a liquid boils and becomes a gas. Shorter, more branched alkanes have higher boiling points as there are weaker London forces between the molecules which require less energy to overcome.
bond enthalpy
the energy required to break one mole of gaseous bonds. Actual bond enthalpies may differ from the average as the average bond enthalpy considers a particular bond in a range of molecules.
complete combustión
when a compound is burnt in a plentiful supply of oxygen. When alkanes are completely combusted, the only products are water and carbon dioxide.
covalent bond
a strong bond formed between 2 atoms due to the electrostatic attraction between a shared pair of electrons and the atomic nuclei.
electron pair repulsion
pairs of electrons around a nucleus repel each other so the shape that a molecule adopts has these pairs of electrons positioned as far apart as possible. As a result, carbon atoms in alkanes have a tetrahedral shape and a bond angle of 109.5°.
homolytic fission
when a covalent bond breaks, each bonding atom receives one electron from the bonding pair, forming 2 radicals.
hydrocarbon
a compound which contains hydrogen and carbon atoms only.
incomplete combustion
when a compound is burnt in a limited supply of oxygen. When alkanes are incompletely combusted, water, carbon monoxide, particulates and some carbon dioxide may be produced.
initiation
the first step in a radical substitution mechanism, involving the formation of the radicals.
london forces
induced dipole-dipole interactions caused when the random movement of electrons creates a temporary dipole in one molecule which then induces a dipole in a neighbouring molecule.
polar bond
a covalent bond that has a permanent dipole due to the different electronegativities of the atoms that make up the bond.
propagation
the intermediate steps in a radical substitution mechanism where a radical reacts with another species.
radical
a species with an unpaired electron,
radical substitution
a type of substitution reaction in which a radical replaces another atom/ group of atoms in a compound. Alkanes can undergo radical substitution reactions with chlorine or bromine in the presence of UV light, forming a mixture of organic products (further substitution or reactions at different positions may occur).
saturated
an organic compound which only contains single C-C bonds.
termination
the final steps in a radical substitution mechanism in which 2 radicals react together to form a species which only contains paired electrons.
tetrahedral
the shape of a molecule in which the central atom has 4 bonding pairs of electrons.
sigma bond
a type of covalent bond which forms when atomic orbitals overlap head-on. Sigma bonds can rotate freely.
pi bond
a type of covalent bond formed when adjacent p orbitals overlap sideways above and below the bonding C atoms. Pi (m) bonds can’t be rotated. As r-bonds have low bond enthalpy, alkenes are more reactive than alkanes.
addition polymerisation
the formation of a long chain molecule when many monomers join together (the polymer is the only product).
addition reaction
a reaction in which molecules combine to form a single product.
alkene
an organic compound containing at least one C=C double bond.
biodegradable
a substance that can be decomposed by bacteria or other living organisms.
biodegradable
a substance that can be decomposed by bacteria or other living organisms.
bond enthalpy
the energy required to break one mole of gaseous bonds. Actual bond enthalpies may differ from the average as the average bond enthalpy considers a particular bond in a range of molecules.
Cahn-Ingold-Prelog (CIP) Priority Rules:
a set of rules used to identify whether a stereoisomer is E or Z. Atoms with a higher atomic number have a higher priority.
catalyst
a substance which increases the rate of a reaction without being used up.
Cis-Trans Isomerism:
a type of E/Z isomerism in which the two substituent groups attached to the cabon atoms are the same.
covalent bond
a strong bond formed between 2 atoms due to the electrostatic attraction between a shared pair of electrons and the atomic nuclei.
electron pair repulsion
pairs of electrons around a nucleus repel each other so the shape that a molecule adopts has these pairs of electrons positioned as far apart as possible. As a result, carbon atoms in alkenes have a trigonal planar shape and a bond angle of 120°.
electrophile
an electron pair acceptor
electrophilic addition
a reaction in which a iT bond is broken and 2 new & bonds form as a result of the addition of an electron pair acceptor (electrophile).
E/Z isomerism
a type of stereoisomerism caused by the restricted rotation of iT bonds. Two different groups must be attached to each carbon atom of the C=C group.
heterolytic fission
when a covalent bond breaks, one bonding atom receives both electrons from the bonding pair, resulting in the formation of oppositely charged ions.
hydrocarbon
a compound which contains carbon and hydrogen atoms only.
Markownikoff’s Rule:
used to predict what the major product of an addition reaction will be when H-X is added to an unsymmetrical alkene. H attaches to the less substituted carbon to generate the more stable carbocation intermediate.
monomer
a small molecule that is used to form polymers.
photodegradable
a substance that can be broken down by light.
polymer
a large molecule made from many small units that have been bonded together.
primary carbocation
a molecule in which the carbon with the positive charge is only attached to one alkyl group. This is the least stable carbocation.
repeat unit
a structure within a polymer that appears over and over again. Joining many repeat units together would form the polymer.
repeat unit
a structure within a polymer that appears over and over again. Joining many repeat units together would form the polymer.
secondary carbocation
a molecule in which the carbon with the positive charge is attached to two alkyl groups. This is more stable than a primary carbocation but less stable than a tertiary carbocation.
stereoisomers
compounds with the same structural formula but a different arrangement of atoms in space.
structural formula
the minimal detail that shows the arrangement of atoms in a molecule.
tertiary carbocation
a molecule in which the carbon with the positive charge is attached to three alkyl groups. This is the most stable type of carbocation.
trigonal planar
the shape of a molecule in which the central atom has 3 bonding pairs of electrons.
unsaturated
an organic compound containing at least one C=C double bond, a C=C triple bond or an aromatic ring. The presence of a C=C double bond means that bromine water will be decolourised.
