Question

Define the following terms, using BaO as an example Write equations to represent each term and state whether the process is exothermic or endothermic (include states) Standard enthalpy of formation Standard lattice enthalpy Standard enthalpy of sublimation for metal and non-metal Standard enthalpy of 1 onisation Standard enthalpy of 2nd ionisation Standard 1t electron affinity Standard 2nd electron affinity a. (0) (n) (u) (Iv) (v) (vi) (vin) (14)

Answer 1

Date ......... Standard enthalpy of formation : The enthalky change that takes place when one mole of substance is formed from its constituents elements in their most stable state of agrregation. Ego- Bacs) + 1021g) - Bao (5) AfH = -55305kI/mol - (exothermic) 1) Standard lattice enthalpy :- The amount of energy required to one mole of ionic solid into acone lituent gaseoul ions. | e9 - 8aO (2) - > Ba(g) +0 g) Tiendothermic) 00 for Standard enthalby of sublimation metal and non-metal : - The enthalky change taking place when Lone mole of solid sublimes at constant temperature and pressure a for Bacs I 8 Bacs) . Ba (9 AH = 180.0kJ/mol It is an endothermic process,

Date ..... iv) Standard enthalpy of ionisation (ast) of The amount lone electron it's gaseous ugy required to from isolated alom ground state release from Lego Ba : [xe7 65² IL (56) Ist excited state :- Bat : - Exe] 65! - DiH, = 503 kJ mol? Energy is required to remove an electron Hence endothermic. v) Standard enthalpy of and lonisation con The amount of en ugy required to remove Land electron from I a monopositive isolated Com. D ego - Bat : [Xe] 651 Ba 2t : [Xe] 65° BiH = 965 KJ molt (Endothermic)

Date I Standard est - electron electron allinite allinity i- - The amount of energer released election in outer most shell fatom in gaseous around state- to add of an an isolated ego Ocgo - 1s² 252 264 ét segH 2 -142 KJ moth I (Exothermic) Standard and electron affinity - and Amount election o- ion of to : envigy the required to add outermost shell of Oig te beg) Segh> 844 KJ molt (Endothermic)