Lattice Enthalpy and the Born-Haber Cycle Flashcards
Module 5
What is lattice enthalpy?
The enthalpy change required to form 1 mole of an ionic lattice from its gaseous ions.
Give an example of an equation for lattice enthalpy.
Na⁺₍₉₎ + Cl⁻₍₉₎ ➡ NaCl₍ₛ₎
What is the name of the enthalpy cycle used to calculate the lattice enthalpy?
It is known as the Born-Haber cycle.
What direction does the step move if it is endothermic?
Endothermic means that the step move up.
What direction does the step move if it is exothermic?
Exothermic means that the step moves down.
State the standard enthalpy change of formation.
It is the enthalpy change required to form one mole of product from its elements in their standard states under standard conditions.
What is the standard enthalpy change of atomisation?
It is the enthalpy change required to form one mole of gaseous atoms from their standard state.
Give an example of a reaction for the standard enthalpy change of atomisation?
X₍ₛ₎ ➡ X₍₉₎
State the first ionisation energy.
It is the energy required to remove one electron from each atom in one mole of gaseous atoms.
Give an example of a reaction for the first ionisation energy.
X₍₉₎ ➡ X⁺₍₉₎ + e⁻
What is the second ionisation energy?
The enthalpy change when one electron is removed from each ion of one mole of gaseous 1+ ions.
Give an example of the second ionisation energy.
X⁺₍₉₎ ➡ X²⁺₍₉₎ + e⁻
What is the first electron affinity?
The enthalpy change when one electron is added to each one atom of one mole of gaseous atoms.
What is the second electron affinity?
The enthalpy change required to add an electron to each ion in one mole of gaseous ions.
Give an example of the first electron affinity?
Y₍₉₎ + e⁻ ➡ Y⁻₍₉₎
Give an example of the second electron affinity?
Y⁻₍₉₎ + e⁻ ➡ Y
