Physical A2 definitions Flashcards
Second ionisation energy
Enthalpy change when one mole of electrons are removed from one mole of gaseous +1 ions to form one mole of gaseous +2 ions under standard conditions.
First ionisation energy
Enthalpy change when one mole of electrons are removed from one mole of gaseous atoms to form one mole of gaseous +1 ions under standard conditions.
First electron affinity
Enthalpy change when one mole of electrons are added to one mole of gaseous atoms to form one mole of gaseous ions with a 1- charge under standard conditions.
Second electron affinity
Enthalpy change when one mole of electrons are added to one mole of gaseous 1- ions to form one mole of gaseous ions with a 2- charge under standard conditions.
Lattice enthalpy of dissociation
Enthalpy change when one mole of solid ionic compound dissociates into its gaseous ions under standard conditions.
Lattice enthalpy of formation
Enthalpy change when one mole of solid ionic compound is formed from its gaseous ions, under standard conditions.
Enthalpy of hydration
Enthalpy change when water molecules surround one mole of gaseous ions, under standard conditions
Enthalpy of solution
Enthalpy change when one mole of solute dissolves completely in sufficient solvent to form a solution in which the molecules or ions are far enough apart to not interact with each other, under standard conditions.
Mean bond enthalpy
Enthalpy change required to break one mole of a covalent bond under standard conditions averaged over a range of compounds.
Entropy
Mathematical measure of how random a system is. The more disordered something is, the greater the entropy. (Units Kmol-1K-1)
Order of reaction
The order of reaction is defined as the power dependence of the rate on the concentration of each reactant.
Rate constant
Is the proportionality constant relating the rate of the reaction to the concentrations of reactants
Brønsted–Lowry acid
A substance that donates a proton (H+)
Brønsted–Lowry base
A substance that can accept a proton.
Strong acids
Acids that fully dissociate into H+ in solution. E.g. HCl, H2SO4, HNO3