definitions Flashcards
Define alicyclic.
Alicyclic - compound containing carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings
Define alicyclic.
Alicyclic - aliphatic compound arranged in non-aromatic rings with/without side chains
Define aromatic.
Aromatic - compound containing a benzene ring
Define cis-trans isomerism.
Cis-trans isomerism - special case of E/Z isomerism in which two of the substituent groups attached to each carbon atom of the C=C group are the same
Define curly arrow.
Curly arrow - movement of a pair of electrons
Define delocalised electrons.
Delocalised electrons - electrons that are shared between more than two atoms
Define electrophile.
Electrophile - electron pair acceptor, attracted to electron-rich region
Define E/Z isomerism.
E/Z isomerism - 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 heterolytic fission.
Heterolytic fission - when a bond breaks & one bonding atom receives both electrons from bonded pair
Define homologous series.
Homologous series - series of organic compounds having the same functional group but with each successive member differing by CH2
Define homolytic fission.
Homolytic fission - when a bond breaks and each bonding atom receives one electron from bonded pair, forming two radicals
Define hydrocarbon.
Hydrocarbon - compound of hydrogen and carbon only
Define nucleophile.
Nucleophile - electron pair donor, attracted to electron-deficient regions
Define optical isomerism.
Optical isomerism - stereoisomerism that are non-superimposable mirror images of each other
Define radical.
Radical - species with an unpaired electron
Define reflux.
Reflux - continual boiling and condensing of a reaction mixture back to original container to ensure that the reaction takes place without the contents of the flask boiling dry
Define saturated.
Saturated - containing single carbon-carbon bonds only
Define stereoisomerism.
Stereoisomerism - compounds have same structural formula but a different arrangement of atoms in space
Define structural isomerism.
Structural isomerism - compounds with same molecular formula but different structural formulae
Define unsaturated.
Unsaturated - presence of multiple carbon-carbon bonds (double/triple/aromatic ring)
Define isotopes.
Isotopes - atoms of same element with different numbers of neutrons and different masses
Define relative atomic mass.
Relative atomic mass - weighted mean mass of an atom compared with 1/12th mass of carbon-12
Define orbital.
Orbital - region around the nucleus that can hold up to two electrons with opposite spins
Define covalent bond.
Covalent bond - strong electrostatic attraction between shared pair of electrons and nuclei of bonded atoms
Define ionic bonding.
Ionic bonding - electrostatic attraction between positive and negative ions
Define metallic bonding.
Metallic bonding - strong electrostatic attraction between cations and delocalised electrons
Define electronegativity.
Electronegativity - ability of an atom to attract the bonding electrons in a covalent bond
Define first ionisation energy.
First ionisation energy - energy required to remove 1 mol of electrons from 1 mol of gaseous atoms to form 1 mol of 1+ ions
Define standard enthalpy change of reaction.
∆rH˚- enthalpy change associated with a stated equation, under standard conditions
Define standard enthalpy change of combustion.
∆cH˚ - enthalpy change when 1 mol of a substance undergoes complete combustion under standard conditions
Define standard enthalpy change of formation.
∆fH˚ - enthalpy change when 1 mol of a compound forms from its elements in their standard states, under standard conditions
Define standard enthalpy change of neutralisation.
∆neutH˚ - enthalpy change when 1 mol of water forms from neutralisation, under standard conditions
Define lattice enthalpy.
∆LEH˚ - enthalpy change that accompanies the formation of 1 mol of ionic lattice from gaseous ions
Define standard enthalpy change of atomisation.
∆atH˚ - enthalpy change that takes place when 1 mol of gaseous atoms forms from the element in its standard state
Define first electron affinity.
∆EA1H˚ - enthalpy change that takes place when one electron is added to each atom in 1 mol of gaseous atoms to form 1 mol of gaseous 1- ions
Define enthalpy change of solution.
∆solH˚ - enthalpy change that takes place when 1 mol of a compound is completely dissolved in water under standard conditions
Define enthalpy change of hydration.
∆hydH˚ - enthalpy change that takes place when 1 mol of isolated gaseous ions is dissolved in water forming 1 mol of aqueous ions under standard conditions
Define entropy.
Entropy - measure of dispersal of energy in a system, greater value means more disordered system
Define rate of reaction.
Rate of reaction - speed at which reactants are being turned into products
Define activation energy.
Ea - minimum energy required for a reaction to take place
Define catalyst.
Catalyst - substance that increases the rate of a chemical reaction without being used up in the process by providing an alternative route for the reaction with lower activation energy
Define half-life.
Half-life - time taken for concentration of a reactant to decrease by half
Define rate-determining step.
Rate-determining step - slowest step in the reaction mechanism of a multi-step reaction, rate equation shows its stoichiometric ratios
Define dynamic equilibrium.
Dynamic equilibrium - equilibrium that exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction and concentrations do not change
Define Brønsted-Lowry acid.
Brønsted-Lowry acid - species that donates a proton
Define Brønsted-Lowry base.
Brønsted-Lowry base - species that accepts a proton
Define alkali.
Alkali - type of base that dissolves in water, forming hydroxide ions
Define buffer.
Buffer - system that minimises pH changes on addition of small amounts of acid or base
Define oxidising agent.
Oxidising agent - species that oxidises (takes electron from) another species
Define reducing agent.
Reducing agent - species that reduces (adds electrons to) another species
Define disproportionation.
Disproportionation - oxidation and reduction of the same element
Define standard electrode potential.
E˚ - electromagnetic field across a half-cell compared with standard hydrogen half-cell measured at standard conditions
Define transition elements.
Transition elements - d-block elements that have an ion with an incomplete d-sub-shell
Define complex ion.
Complex ion - transition metal ion bonded to ligands by coordinate bonds (dative covalent bonds)
Define coordination number.
Coordination number - total number of coordinate bonds formed between a central metal ion and ligands
Define bidentate ligand.
Bidentate ligand - ligand with two lone pairs, both of which can bond to central metal ion
