`Fe_(2)O_(2)(s)+(3)/(2)C(s)to(3)/(2)CO_(2)(g)+2Fe(s)`
`DeltaH^(@)=+234.12KJ `
`C(s)+O_(2)(g)toCO_(2)(g) DeltaH^(@)=-393.5KJ`
Use these equations and `DeltaH^(@)` value to calculate `DeltaH^(@)` for this reaction :
`4Fe(s)+3O_(2)(g)to2Fe_(2)O_(3)(s)`

Options

A. `-1648.7kJ`
B. `-1255.3 kJ`
C. `-1021.2kJ`
D. `-129.4kJ`

Answer

A

Explanation

`2Fe(s)+(3)/(2)CO_(2)(g)toFe_(2)O_(3)(s)+(3)/(2)C(s)" "(DeltaH^(@)=-234.1kJ)` . . .(i)
`C(s)+O_(2)(g)toCO_(2)(g)" "(DeltaH^(@)=-393.5kJ)` . . . (ii)
Multiplying eq. (i) by 2 and eq. (ii) by 3 and on adding both equations, we get:
`4Fe(s)+3O_(2)(g)to2Fe_(2)O_(3)(s)," "DeltaH^(@)=(-234.1xx2)+(-3xx393.5)`
`=-1648.7kJ`