There are two crystalline forms of PbO , one is yellow and the other isred. The standard enthalpies of formation of thesetwoforms are - 217.3 and -219.0 kJ per mole respectively. Calculate the enthalpy change for the solid - solid phase transition. PbO( yellow ) rarrPbO ( red)

There are two crystalline forms of PbO , one is yellow and the other i

1.	There are two crystalline forms of PbO , one is yellow and the other isred. The standard enthalpies of formation of thesetwoforms are - 217.3 and -219.0 kJ per mole respectively. Calculate the enthalpy change for the solid - solid phase transition. PbO( yellow ) rarrPbO ( red)
Answer» Solution :Given `: (i) Pb(s) + (1)/(2) O_(2)(g) rarr PbO ` ( yellow ) , `Delta H = - 217. 3 kJ mol^(-1)` (II) `Pb(s) + (1)/(2) O_(2)(g) rarr PbO(` Red)`, Delta H = - 219 .0 kJ mol^(-1)` Eqn. (ii) - Eqn. (i) GIVES the requiredresult.