Enthalpy Definitions Flashcards
Enthalpy change of Reaction
The enthalpy change when the reaction occurs in the molar quantities shown in the chemical equation , under standard conditions and states
Enthalpy change of Combustion
The enthalpy change when 1 mol of element or compound reacts completely with oxygen under standard conditions and states
Enthalpy change of Neutralisation
The enthalpy change associated with forming 1 mole of water from a neutralisation reaction, under standard conditions
Enthalpy change of Formation
Enthalpy change due to 1 mole of compound forming from its constituent elements, under standard conditions
=> (exo- or endo- thermic)
Enthalpy change of Atomisation
Enthalpy change by forming 1 mol of atoms (g) from elements, in standard states and conditions
=> (endothermic)
Lattice Enthalpy
Enthalpy change due to forming 1 mole of ionic lattice from ions (g)
=> (exothermic)
Lattice dissociation enthalpy
Enthalpy change when 1 mol of solid ionic compound separates into ions (g
=> (endothermic)
First ionisation energy
Enthalpy change required to remove 1 electron from each atom in 1 mole of atoms (g) to form 1 mole of +1 ions (g)
Second ionisation energy
Enthalpy change required to remove 1 electron from each ion in 1 mole of +1 ions (g) to form +2 ions (g)
First electron affinity
Enthalpy change when an electron is added to each atom in 1 mol of atoms (g) to form 1 mole of -1 ions (g)
=> exothermic
Second electron affinity
Enthalpy change when an electron is added to each ion in -1 ions (g) to form -2 ions (g)
=> endothermic
Mean bond enthalpy
Enthalpy change when 1 mol of molecules (g) each breaks acovalent bond to form 2 free radicals, averaged over a range of compounds
=> endothermic
Enthalpy of hydration
Enthalpy change when ions (g) are dissolved in water to form 1 mole of ions (aq)
=> exothermic
Enthalpy of solution
Enthalpy change when 1 mole of solute dissolves completely in a solvent
=> exo- or endo- thermic
