If the enthalpy of combustion of diamond and graphite are `-395.4 kJ mol^(-1)` and `-393.6 kJ mol^(-1)`, what is enthalpy change for the `C("graphite") rarr C("diamond")`?

Explanation

`C("diamond") +O_(2)(g) rarr CO_(2)(g) DeltaH =- 395.4 kJ mol^(-1)………(i)`
`C("graphite") +O_(2)(g) rarr CO_(2)(g) DeltaH =- 393.6 kJ mol^(-1) …..(ii)`
`C("graphite") rarr C ("diamond")`
Subtracting equation (i) from equation (ii), we get
`C("graphite") rarr C("diamond")`
`DeltaH = -393.6 kJ -(-395.4 kJ)`
`DeltaH = +1.8 kJ mol^(-1)`.