Calculate the standard enthalpy of formation of CH,OH() from the following
data:
3
CH,OH (1) +
2
0,(g) → CO(g) + 2H,O(): A Hº = -726 kJ mol
C(graphite) + 0,(g) → CO,(g) : AH = -393 kJ mol
H,(g) +
2
0,(g) → H,0(l): 4, Hº = -286 kJ mol'.
Answers
Answer:
Answer
By Hess Law,
For finding the standard enthalpy of formation of FeO(s)
Fe(s)+CO(g)→C(graphite)+FeO(s) −155
(graphite)+O
2
(g)→CO
2
(g) −393
CO
2
(g)→CO(g)+
2
1
O
2
(g) 282
∴△H
r
(For the formation of FeO)(S)
i.e. for Fe(S)+
2
1
O
2
(g)→FeO(S)
=−155−393+282=−266
By Hess law, For finding the standard enthalpy of formation of Fe
2
O
3
(S)
2Fe(S)+3CO(g),→3c(graphite)+Fe
2
O
3
(S) −492
3c(graphite)+3O
2
(g)→3CO
2
(g) −3×393
3CO
2
(g)→
2
3
O
2
(g)+3CO(g) 3×282
2Fe(S)+
2
3
O
2
(g)→2CO(g)+Fe
2
O
3
(S)
△H
r
=−492+(−3×393)+(3×282)
=−825