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Byju's Answer
Standard XII
Chemistry
Hess' Law
From the foll...
Question
From the following data at
25
∘
C
, The standard enthalpy of formation of FeO(s) is X, then 0.3-X is:
Reaction
Δ
r
H
∘
( kJ / mole )
F
e
2
O
3
(
s
)
+
3
C
(
g
r
a
p
h
i
t
e
)
→
2
F
e
(
s
)
+
3
C
O
(
g
)
492.6
F
e
O
(
s
)
+
C
(
g
r
a
p
h
i
t
e
)
→
F
e
(
s
)
+
C
O
(
g
)
155.8
C
(
g
r
a
p
h
i
t
e
)
+
O
2
(
g
)
→
C
O
2
(
g
)
−
393.51
C
O
(
g
)
+
1
/
2
O
2
(
g
)
→
C
O
2
(
g
)
−
282.98
Open in App
Solution
F
e
O
(
s
)
+
C
(
g
r
a
p
h
i
t
e
)
⟶
F
e
(
s
)
+
C
O
(
g
)
,
155.8
C
O
(
g
)
+
1
2
O
2
(
g
)
⟶
C
O
2
(
g
)
,
−
282.98
+
F
e
O
(
s
)
+
C
(
g
r
a
p
h
i
t
e
)
+
1
2
O
2
(
g
)
⟶
F
e
(
s
)
+
C
O
2
(
g
)
,
△
H
=
−
127.18
C
+
O
2
⟶
C
O
2
,
−
393.51
-
F
e
O
−
1
2
O
2
⟶
F
e
,
266.33
⇒
F
e
+
1
2
O
2
⟶
F
e
O
,
△
H
=
−
266.33
0.3
−
(
266.33
)
=
266.63
≈
267
Suggest Corrections
0
Similar questions
Q.
From the following data at 25C, Calculate the standard enthalpy of formation of FeO(s) and of
F
e
2
O
3
(
s
)
.
Reaction
Δ
r
H
(
K
J
/
m
o
l
e
)
(1)
F
e
2
O
3
(
s
)
+
3
C
(
g
r
a
p
h
i
t
e
)
→
2
F
e
(
s
)
+
C
O
(
g
)
492
(2)
F
e
O
(
s
)
+
C
(
g
r
a
p
h
i
t
e
)
→
F
e
(
s
)
+
C
O
(
g
)
155
(3)
C
(
g
r
a
p
h
i
t
e
)
+
O
2
(
g
)
→
C
O
2
(
g
)
-393
(4)
C
O
(
g
)
+
1
/
2
O
2
(
g
)
→
C
O
2
(
g
)
-282
Q.
From the data at
25
o
C
:
F
e
2
O
3
(
s
)
+
3
C
g
r
a
p
h
i
t
e
⟶
2
F
e
(
s
)
+
3
C
O
(
g
)
;
Δ
H
o
=
492
k
J
/
m
o
l
F
e
O
(
s
)
+
C
g
r
a
p
h
i
t
e
⟶
F
e
(
s
)
+
C
O
(
g
)
;
Δ
H
o
=
155.8
k
J
/
m
o
l
C
g
r
a
p
h
i
t
e
+
O
2
(
g
)
⟶
C
O
2
(
g
)
;
Δ
H
o
=
−
393.51
k
J
/
m
o
l
C
O
(
g
)
+
1
2
O
2
(
g
)
⟶
C
O
2
(
g
)
;
Δ
H
o
=
−
282.98
k
J
/
m
o
l
Calculate standard heats of formation of
F
e
O
(
s
)
and
F
e
2
O
3
(
s
)
.
Q.
The following two reactions are known
F
e
2
O
3
(
s
)
+
3
C
O
(
g
)
→
2
F
e
(
s
)
+
3
C
O
2
(
g
)
;
Δ
H
=
−
26.8
k
J
F
e
O
(
s
)
+
C
O
(
g
)
→
F
e
(
s
)
+
C
O
2
(
g
)
Δ
H
=
−
16.5
k
J
The value of
Δ
H
for the following reaction is:
F
e
2
O
3
(
s
)
+
C
O
(
g
)
→
2
F
e
O
(
s
)
+
C
O
2
(
g
)
Q.
Calculate the standard enthalpy of formation of
C
H
3
O
H
(
l
)
from the following data.
C
H
3
O
H
(
l
)
+
3
2
O
2
(
g
)
→
C
O
2
(
g
)
+
2
H
2
O
(
l
)
;
Δ
H
o
=
−
726
kJ
m
o
l
−
1
C(graphite)
+
O
2
(
g
)
→
C
O
2
(
g
)
;
Δ
c
H
0
=
−
393
kJ
m
o
l
−
1
H
2
(
g
)
+
1
2
O
2
(
g
)
→
H
2
O
(
l
)
;
Δ
t
H
o
=
−
286
kJ
m
o
l
−
1
.
Q.
Given the following data :
Determine at what temperature the following reaction is spontaneous ?
F
e
O
(
s
)
+
C
(
g
r
a
p
h
i
t
e
)
⟶
F
e
(
s
)
+
C
O
(
g
)
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