Unit 4 Definitions Flashcards
Enthalpy of atomisation
The enthalpy change when one mole of gaseous atoms is formed from the element in its standard state
Electron affinity
The enthalpy change when one mole of gaseous ions is converted into gaseous ions with a single negative charge
Enthalpy of solution
The enthalpy change when one mole of a solute dissolves in water
Enthalpy of hydration
The enthalpy change when one mole of gaseous ions is converted into one mole of aqueous ions
Feasible
A reaction in which delta G =
Entropy
A measure of disorder (randomness)
Order of reactants (with respect to a reactant)
The power to which the concentrations of a reactant is raised in the rate equation
Order of reaction (overall)
The sum of the powers to which the concentration terms are raised in the rate equation
Rate constant
The proportionality constant which links the rate of the reaction to the concentrations in the rate equation
Rate determining step
The slowest step in the mechanism
Mole fraction of a gas
Number of moles of a particular gas/ total number of moles of gas
Concentration
Number of moles/volume
Partial pressure
Mole fraction X total pressure
Partition Coefficient
Concentration in upper layer at equilibrium/ concentration in power layer at equilibrium
Brønsted acid
Proton donor
Brønsted Base
Proton acceptor
Strong acid or base
Fully dissociates
Weak base or acid
Partially dissociates
Kw
[H+][OH-]
Ka
[A-][H+] / [HA]
pH
-log[H+]
Buffer solution
A solution which resists changes in pH on addition of small amounts of acid or alkali
Monobasic acid
Donates one proton per molecule
Asymmetric centre
A carbon which has four different atoms of groups attached
Optical isomers
Molecules which exist as non-superimposable mirror images
Optically active
A sample which rotates the plane of plane of polarised light
Iodine value
The mass of iodine in g required to completely saturate 100g of a fat or oil
Saponification value
The mass of KOH in mg required to completely hydrolyse 1.0g of a fat or oil
Polulyunsaturated
Contains two or more C=C bonds
Amphoteric oxide
Reacts with both acids and bases
Receamic
A 50:50 mixture of optical isomers
Lattice enthalpy
The enthalpy change when one mole of an ionic compound is converted to gaseous ions
