Question

Calculate the heat of formation of n butane from the followinf data:
a. `2C_(4)H_(10)(g) +13O_(2)(g) rarr 8CO_(2)(g) +10H_(2)O(l), DeltaH = - 5757.2 kJ`
b. `C(s) +O_(2) (g)rarrCO_(2)(g), DeltaH =- 405.4 kJ`
c. `2H_(2)(g) +O_(2)(g) rarr 2H_(2)O(l), DeltaH =- 572.4 kJ`

Answer 1

To calculate `DeltaH` of the following reaction
`4C(s) +5H_(2)(g) rarr C_(4)H_(10)(g) DeltaH = ?`
`DeltaH = 4DeltaH_(2) +(5)/(2) DeltaH_(3) -(1)/(2)DeltaH_(1)`
`= 4 xx (-405.4) +(5)/(2) xx (-572.4) -(1)/(2) (-5757.2)`
`=- 1621.6 - 1431 +2878.6`
`=- 3052.6 +2878.6`
`=- 174 kJ mol^(-1)`