definitions Flashcards
atomisation
1 mole of gaseous atoms formed
combustion
1 mole of substance burned with excess oxygen
hydration
1 mole of gaseous ions dissolved sufficient water to form a very dilute solution
neutralisation
1 mole of water formed from alkali and acid
solution
1 mole of ionic solid dissolved sufficient water to form a very dilute solution
lattice energy
energy change of 1 mole of an ionic compound formed from its gaseous ions
SEP
voltage produced when a standard half-cell (1.00 moldm-3 298K) is connected to standard hydrogen electrode
under sc
SCP
diff between the 2 sep between two specified half cells
kw
equ constant of ionisation of water
ka
the equilibrium constant for the dissociation of a weak acid
adsorption
1st stage in heterogenous catalysis, when reactant molecules make bonds with atoms on the catalyst surface
bidentate ligand
a ligand that forms two coordinate bonds to the central transition metal ion in a complex
bond energy
the energy required to break one mole of a particular covalent bond in the gaseous state
units : kJmol-1
buffer solution
a solution that minimises significant changes in the pH when small amounts of acids and alkalis are added
carbocation
an alkyl group with a single positive charge on one of its carbon atoms, CH3+
catalysis
the increase in rate of a chemical reaction brought about by the addition of particular substance which is not used up by the reaction
desorption
last stage in heterogeneous catalysis
bonds holding the molecular of product to the surface of the catalyst are broken, and the product molecules diffuse away from the surface of the catalyst
diazotisation
the reaction between phenylamine and nitrous acid(HNO2) to give a diazonium salt in the first step in preparing azo dye
electronegativity
the power of a particular atom that is covalently bonded to another atom to attract the bonding pair of electrons towards itself
electrophilic sub
the replacement of an atom by another atom or group of atoms after initial attack by an electron-deficient species
electrophoresis
the separation of ions placed in an electric field between a positive and a negative electron
enantiomers
a pair of optically active molecules whose mirror images cannot be superimposed
enthalpy change
the heat energy transferred during a chemical reaction
entropy
the no. of possible arrangements of the particles an their energy in a given system
Gibbs full name
Gibbs free energy change
ligand
a species with one or more lone pairs of electron that form dative covalent bonds to a central transition metal atom or ion
mobile phase
the solvent used in chromatography, which moves along the paper, thin layer of aluminum oxide or column containing liquid supported on a solid
2nd EA
the enthalpy change when 1 mole of electrons is added to 1 mole gaseous 1- ions to form 1 mole of gaseous 2- ions under sc
ion polarisation
the distortion of the electron cloud of an anion by a neighbouring cation.
distortion greates when cation is small and highly charged
polarising power
the ability of a cation to attract the electron cloud of an anion and distort it
ion-dipole bond
the bond formed between an ion and a polar compound such as water.
The negative end of the dipole with positive ion
positive end of dipole with negative ion
electrolysis
the decomposition of an ionic compound when molten or in aqueous solution by an electric current
nerst formula
E (under non sc) = E (under sc) + 0.059/z log[oxidised/reduced]
at ROOM TEMP 25
if not, then
E (under non sc) = E (under sc) + RT/zF log[oxidised/reduced]
oxidised Fe3+
reduced Fe2+
oxidised is the one thats ALREADY been oxidised
for metal/metal ion electrode
reduced is Metal,
conc of metal does not change so
E (under non sc) = E (under sc) + 0.059/z log[oxidised]
conjugate pair
an acid-base pair on each side of an acid-base equilibrium equation that are related to each other by the difference of a hydrogen ion
solubility product
the product of the concs of each ion in a saturated solution of a sparingly soluble salt at 298k, raised to the power of their relative concs
partition coefficient
the ratio of the conc of a solute in two immiscible solvents in contact with each other when equilibrium is esstablished.
order of reaction
the power to which the conc of the reactant is raised in the rate equation
half life
the time taken for the amount/conc of the limiting reactant in a reaction to decrease to half its initial value
Limiting reactant
the reactant which is not in excess
homogenous catalysis
the type of catalysis in which the catalyst and reactants are in the same phase
heterogenous catalysis
the type of catalysis in which the catalyst and reactants are in the different phase
ggibbs free energy change
the energy change that takes into account both the entropy change of a reactionn and the enthalpy change
coordination no.
the nomber of cooridante bonds formed by ligands with a transition element ion in a complex
electrophoresis
the separation of ions place in an elcetric field between a posivit and a negative electrode
entropy
the number of possible arrangemtnets of the particles and their energy in a given system
complex
a molecule or ion formed by a metal ion surrounded by one or more ligands, dative covalently bonded
kstab
the equilibrium constant for the formation of the
complex ion in a solvent (from its constituent ions or molecules)
