Definitions Flashcards
Lattice enthalpy
The enthalpy change when 1 mol of an ionic compound is converted into gaseous ions
Enthalpy of atomisation
The enthalpy change when 1 mol of gaseous atoms is formed from the element in its standard state
First electron affinity
The enthalpy change when 1 mol of gaseous atoms is converted into gaseous ions with a single negative charge
Enthalpy of solution
The enthalpy change when 1 mol of a solute dissolves in water
Enthalpy of hydration
The enthalpy change when 1 mol of gaseous ions is converted to 1 mol of aqueous ions
Feasible
A reaction for which 🔼G less than 0
Delta G less than 0
Entropy
A measure of disorder (randomness)
Free energy
🔼G = 🔼H - T🔼S
Rate of reaction
The change of the concentration of a reactant or product with respect to time
Order of reaction (with respect to a reactant)
The power to which the concentration 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 of a reaction
Brønsted acid
Proton donor
Brønsted base
Proton acceptor
Kw
Kw = [H+][OH-]
Ka
Ka = [H+][A-]
—————
[HA]
pH
pH = -log [H+]
pKw
pKw = -log (Kw)
pKa
pKa = -log (Ka)
Buffer solution
A solution which resists changed in pH on addition of small amounts of acid or alkali
Monobasic acid
Donates one proton per molecule
Asymmetric (chiral) isomer
An atom which has 4 different atoms or groups attached
Optical isomers
Molecules which exist as non-superimpossible mirror images
Optically active
A sample which rotates the plane of plane polarised light
Racemic mixture
A 50:50 mixture of two optical isomers
Monoester
An ester which contains only one Ester group
Transesterification
A reaction where the alkyl group of an ester is exchanged with the alkyl group of an alcohol
Biodiesel
A fuel, similar to diesel, which is made from vegetable sources. Eg from the reaction of rapeseed oil with methanol
Delocalisation
The Pi electrons are spread over several atoms
