The Born-Haber process is used to determine the enthalpy of formation of common salts as it is the hardest process to measure. For KBr the enthalpy of formation follows this equation:
2 K(s) + Br2(g) ? 2 KBr(s)
Calculate the standard formation enthalpy of potassium bromide from
the following known standard enthalpies:
K(s) ? K(g) ?Hsub =89kJ
K(g) ? K+(g) + e- ?HI = 419 kJ
Br2(g) ? 2 Br(g) ?HD = 192.8 kJ
Br(g) + e- ? Br-(g) ?HEA = -325 kJ
KBr(s) ? K+(g) + Br-(g) ?HU = 691 kJ