born haber cycle

Question 1

enthalpy of 1st ionisation energy

Answer 1

the enthalpy change when one mole of a gaseous 1+ ion is formed from one mole of its gaseous atom
Na(g) –> Na+(g) + e-
endothermic : Requires energy

Question 2

enthalpy of 2nd ionisation energy

Answer 2

the enthalpy change when one mole of a gaseous 2+ ion is formed from one mole of its gaseous 1+ ion
Na+(g) –> Na2+(g) + e-
endothermic : Requires energy

Question 3

enthalpy of 1st electron affinity

Answer 3

the enthalpy change when one mole of a gaseous 1- ion is formed from one mole of its gaseous atom
Cl(g) + e- –> Cl-(g)
exothermic : energy is released

Question 4

enthalpy of 2nd electron affinity

Answer 4

the enthalpy change when one mole of a gaseous 2- ion is formed from one mole of its gaseous 1- ion
O-(g) + e- –> O2-(g)
endothermic: Requires energy. The 2nd electron affinity of oxygen is high as the electron is being forced into a small, electron-dense space.

Question 5

enthalpy of atomisation

Answer 5

enthalpy change when one mole of a gaseous atom is formed from elements in their standard states
1.5Cl2(g) –> Cl2(g)
endothermic : Requires energy

Question 6

lattice formation enthalpy

Answer 6

enthalpy change when one mole of a solid ionic compound is formed from its gaseous ions
Na+(g) + Cl-(g) –> NaCl(s)
exothermic : energy is released

Question 7

lattice dissociation enthalpy

Answer 7

enthalpy change when one mole of an ionic compound dissociates into its gaseous ions
NaCl(s) –> Na+(g) + Cl-(g)
endothermic : Requires energy

Question 8

standard enthalpy of hydration

Answer 8

enthalpy change when one mole of a aqueous ions are formed from its gaseous ions
Na+(g) + Cl-(g) –> Na+(aq) + Cl-(aq)
exothermic : energy is released

Question 9

standard enthalpy of solution

Answer 9

enthalpy change when one mole of a solute is dissolved in enough solute that no further enthalpy change occurs on further dilution
KCl(s) –> KCl(aq)
endo/exo