definitions Flashcards
Activation energy
The minimum amount of kinetic energy that particles need to have in order to react when they collide
Addition polymer
A long chain molecule formed by an addition reaction
Alcohol
Substance with general formula CnH2n+1OH
Aldehyde
A substance with general formula CnH2nO which has a hydrogen and one alkyl group attached to the carbonyl carbon atom
Alkane
Hydrocarbon with the general formula CnH2n+2
Alkene
Hydrocarbon with the general formula CnH2n, containing at least one carbon-carbon double bond
Atom economy
A measure of the proportion of reactant atoms that become part of the desired product in a balanced chemical reaction
Atomic number
The number of protons in the nucleus of an atom
Avogadro’s constant
6.02 x 10^23
Number of particles in one mole of a substance
Barium meal
A suspension of barium sulphate swallowed by a patient before an x-ray
Benedicts solution
A deep blue solution containing Cu2+ ions which are reduced to a brick-red precipitate of Cu2O when warmed with an aldehyde, stays blue when warmed with a ketone
Biofuel
Fuel made from biological material thats recently died
Bond enthalpy
The enthalpy required to break a bond between two atoms
Calorimetry
Method of finding out how much energy is given out or taken in by a reaction
Carbocation
An organic ion containing a positively charged carbon atom
Carbonyl compound
A compound that contains a carbon-oxygen double bond
Carboxylic acid
A substance which has a COOH group attached to the end of a carbon chain
Catalyst
A substance that increases the rate of reaction by providing an alternative pathway with a lower activation energy. It is chemically unchanged
Chain isomer
Organic molecule that contains the same atoms and functional groups as another molecule but has a different arrangement of the carbon skeleton
Charge cloud
An area in an atom or molecule where theres a high chance of finding an electron pair
Chloroalkane
An alkane with one or more hydrogen atoms substituted for chlorine atoms
Closed system
A system where nothing can get in or out
Collision theory
The theory that a reaction will not take place between two particles unless they collide in the right direction with a certain minimum amount of kinetic energy
Complete combustion
Burning a substance completely in oxygen to produce carbon dioxide and water only
Co-ordinate bond (Dative covalent)
A covalent bond formed when one atom provides both of the shared electrons
Covalent bond
A pair of electrons shared between two atoms
Cracking
Breaking longer chain alkanes into smaller hydrocarbons
Crude oil
Mixture consisting mainly of alkane hydrocarbons that can be separated into different fractions
Cycloalkane
A type of alkane where the carbon atoms form a ring, with two hydrogen atoms attached to each carbon
Dehydration
Reaction where water is eliminated
Dipole
Difference in charge between two atoms caused by a shift in the electron density in a bond
Displacement reaction
A reaction where a more reactive element pushes out a less reactive element and takes its place
Disproportionation
When an element is both oxidised and reduced in a single chemical reaction
Dynamic equilibrium
In a reversible reaction, dynamic equilibrium is reached when the concentrations of the reactants and products are constant and the forward and reverse reactions are equal
E-Isomer
A stereoisomer of an alkene that has two highest priority groups on opposite sides of the carbon - carbon double bond
Electronegativity
The power of an atom to attract the bonding electrons in a covalent bond
Electrophile
Electron-pair acceptor
Electrophilic addition
Reaction mechanism where a C=C bond in an alkene opens up and atoms are added to the carbon atoms
Electrospray ionisation
Method of producing ions for analysis in a mass spectrometer by applying high pressure and high voltage to a sample of a substance
Elimination reaction
A reaction in which a molecule loses an atom or groups or atoms
Empirical formula
A formula that gives you the simplest ratio of atoms of each element in a compound
Endothermic reaction
Reaction which absorbs energy
Positive value for enthalpy change
Equilibrium constant
A ratio worked out from the concentration of the products and reactants once a reversible reaction has reached equilibrium
Exothermic reaction
Reaction which gives out energy
Negative value for enthalpy change
E/Z isomerism
Type of stereoisomerism caused by restricted rotation around the double bond
Fehling’s solution
Deep blue Cu2+ complex which reduces to a brick red Cu2O precipitate when warmed with an aldehyde and stays blue when warmed with a ketone
Fingerprint region
Region between 1000cm3 and 1550cm3 on an infrared spectrum which is unique to a particular compound
First ionisation energy
The energy needed to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous +1 ions
Fractional distillation
Method of separating crude oil fractions using their boiling points
Free radical
A particle with an unpaired electron
Functional group
Group of atoms which is responsible for the characteristic reactions of a molecule
Functional group isomer
A molecule with the same molecular formula as another molecule, but with the atoms arranged into different functional groups
Giant covalent structure
A structure consisting of a huge network of covalently bonded atoms
Giant ionic lattice structure
A regular repeated structure made up of oppositely charged ions and held together by electrostatic attraction
Giant metallic lattice structure
A regular structure consisting of closely packed positive metal ions in a sea of delocalised electrons
Greenhouse effect
The trapping of energy from the sun that has been absorbed and re-emitted by the earth
Halide
Negative ion of a halogen
Halogenoalkane
An alkane with at least one halogen atom in place of a hydrogen atom
Hess’ Law
The total enthalpy change for a reaction is independent of the route taken
