Bonn-Haber definitions Flashcards
(20 cards)
What is the definition of Enthalpy of Formation (ΔH_f)?
Enthalpy change when one mole of a substance is formed from its constituent elements with all substances in their standard states
Is Enthalpy of Formation (ΔH_f) exothermic or endothermic?
Exothermic (-ve) for most substances
What is the definition of Enthalpy of Combustion (ΔH_c)?
Enthalpy change when one mole of a substance undergoes complete combustion in oxygen with all substances in standard states
Is Enthalpy of Combustion (ΔH_c) exothermic or endothermic?
Exothermic (-ve)
What is the definition of Ionisation Enthalpy (ΔH_i)?
The first ionisation energy is the enthalpy change when one mole of gaseous atoms loses one electron per atom to produce gaseous 1+ ions. The second ionisation energy is when one mole of gaseous 2+ ions is produced from one mole of 1+ ions.
Is Ionisation Enthalpy (ΔH_i) exothermic or endothermic?
Endothermic (+ve)
What is the definition of Electron Affinity (ΔH_ea)?
The first electron affinity is the enthalpy change when one mole of gaseous atoms gains one electron per atom to produce gaseous 1- ions. The second electron affinity is the enthalpy change when one mole of gaseous 1- ions gains one electron per ion to produce gaseous 2- ions.
Is Electron Affinity (ΔH_ea) exothermic or endothermic?
Exothermic (-ve) for many non-metals; Endothermic (+ve) for the second electron affinity
What is the definition of Enthalpy of Atomisation (ΔH_a)?
Enthalpy change when one mole of gaseous atoms is produced from an element in its normal state.
Is Enthalpy of Atomisation (ΔH_a) exothermic or endothermic?
Endothermic (+ve)
What is the definition of Hydration Enthalpy (ΔH_hyd)?
Enthalpy change when one mole of gaseous ions becomes hydrated (dissolved in water).
Is Hydration Enthalpy (ΔH_hyd) exothermic or endothermic?
Exothermic (-ve)
What is the definition of Enthalpy of Solution (ΔH_sol)?
Enthalpy change when one mole of an ionic solid dissolves in an amount of water large enough so that the dissolved ions are well separated and do not interact with each other.
Is Enthalpy of Solution (ΔH_sol) exothermic or endothermic?
Varies
What is the definition of Bond Dissociation Enthalpy (ΔH_b)?
Enthalpy change when one mole of covalent bonds is broken in the gaseous state.
Is Bond Dissociation Enthalpy (ΔH_b) exothermic or endothermic?
Endothermic (+ve)
What is the definition of Lattice Enthalpy of Formation (ΔH_L)?
Enthalpy change when one mole of a solid ionic compound is formed from its constituent ions in the gas phase.
Is Lattice Enthalpy of Formation (ΔH_L) exothermic or endothermic?
Exothermic (-ve)
What is the definition of Lattice Enthalpy of Dissociation (ΔH_L)?
Enthalpy change when one mole of a solid ionic compound is broken up into its constituent ions in the gas phase.
Is Lattice Enthalpy of Dissociation (ΔH_L) exothermic or endothermic?
Endothermic (+ve)
