Determine the standard enthalpy of formation of FeO(s) and `Fe_(2)(O_(3)(s)` from the following data :
`3C("graphite",s) +Fe_(2)O_(3)(s) to 2 Fe(s)+3CO(g), Delta H^(0)= 492.6 kJ`
`C("graphite",s)+FeO(s) to Fe(s)+CO(g), Delta H^(0)= 155.8 kJ`
`C( "graphite",s)+O_(2)(g) to CO_(2)(g),Delta H^(0)= -393.51 kJ`
`CO(g)+(1)/(2)O_(2)(s) to CO_(2)(g), Delta H^(0)= -282.98 kJ`

Explanation

`2 xx eq. [3]-2 xx eq.[4] - 2xx eq.[2]`, we have , `2Fe(s)+O_(2)(g) to 2FeO(s), Delta H^(0)= [2(-393.51)-2(-282.98)-2 (155.8)] kJ= -532.66 kJ`
`therefore Fe(s)+(1)/(2)O_(2)(g) to FeO(s), Delta H= - (1)/(2)xx532.66= - 266.33 kJ`
`3xx eq. (3)-3xxeq. (4)-1xxeq(1)`, we have, `2Fe(s)+(3)/(2)O_(2)(g) to 2Fe_(2)O_(3)(s)`
`Delta H^(0)= [ 3(-393.51)-3 (-282.98)- 492.6] kJ = -824.2 kJ`