Inorganic and foundations definitions Flashcards
Define acid
A speices that releases H+ ions in aqueous solution
Define acid dissociation constant Ka
The equilibrium constant that shows the extent of dissociation of a weak acid.
For weak acid HA Ka=[H+ (aq)] [A-(aq)] / [HA(aq)]
Define acid-base pair
A pair of two species that transform into each other by gain or loss of a proton
Define activation energy
The minimum energy required to start a reaction by the breaking of bonds
Actual yield
The amount of product obtained from a reaction
Addition reaction
A reaction in which a reactant is added to an unsaturated molecule to make one saturated molecule
Define adsorption
The process that occurs when a gas or liquid or solute is held to the surface of a solid
Define alkali
A type of base that dissolves in water forming hydroxide ions
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 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 average bond enthalpy
The average enthalpy change that takes place when breaking by homolytic fission 1 mol of a given type of bond in the molecules of a gaseous species
Define Avogadro constant
The number of atoms per mole of the carbon-12 isotope (6.023*10^23 mol-1)
Define base
A proton acceptor. A compound that neutralises an acid to form a salt
Define 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 buffer solution
A system that minimises pH changes on addition of small amounts of an acid or base
Define catalyst
A substance that increases the rate of a chemical reaction without being used up in the process; a catalyst provides an alternative route for the reaction with lower activation energy
Define cation
A positively charged ion with fewer electrons than protons
Define closed system
A system isolated from its surroundings
Define collision theory
Two reacting particles must collide for a reaction to occur, and must be in the correct orientation and have sufficient energy to overcome the activation energy of the reaction
Define complex ion
A transition metal ion bonded to ligands by coordinate bonds
Define concentration
The amount of solute, in mols dissolved in 1 dm3 of solution
Define conjugate acid
A species that releases a proton to form a conjugate base
Define a conjugate base
A species that accepts a proton to form a conjugate acid
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 coordination number
THe total number of coordinate bonds formed between a central metal ion and ligands
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 desorption
Release of an adsorbed substance from a surface
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 displacement reaction
A reaction in which a more reactive element displaces a less reactive element from an aqueous solution of its ions
Define disproportionation
A redox reaction in which the same element is both oxidised and reduced
Define dynamic equilibrium
The 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 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 electrons in a covalent bond
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 end point
The point in a titration where the indicator changes colour; the endpoint indicated when the reaction is just complete
Define endothermic reaction
A reaction in which the enthalpy of the products is greater than the enthalpy of the reactants, resulting in heat being taken in from the surroundings
Define enthalpy
The heat content that is stored in a chemical system
Define enthalpy change
The difference between the enthalpy of the products and the enthalpy of the reactants
Define enthalpy cycle
A diagram showing alternative routes between reactants and products which allows the indirect determination of an enthalpy change from other known enthalpy changes using Hess’s law
Define entropy
Used to describe the dispersal of energy and disorder within the chemicals making up the chemical system
Define equilibrium constant
A measure of the position of equilibrium; the magnitude of an equilibrium indicates whether there are more reactants or more products in an equilibrium system
Define equivalence point
The point in a titration at which the volume of one solution has reacted exactly with the volume of the second solution
Define exothermic reaction
A reaction in which the enthalpy of the products is smaller than the enthalpy of the reactants resulting in heat loss to the surroundings
Define first electron affinity
The enthalpy change that takes place when one electron is added to each atom in one mole of gaseous atoms to form one mole of gaseous 1- ions
Define first ionisation energy
The energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions
Define free energy change deltaG
The balance between enthalpy, entropy and temperature for a process.
Given by ΔG= ΔH-T ΔS
A process is feasible when ΔG<0
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