Calculate the heat of transition for carbon from the following:
`C_("Diamond") +O_(2) rarr CO_(2)(g),DeltaH =- 94.3 kcal`
`C_("Amorphous") +O_(2) rarr CO_(2)(g),DeltaH =- 97.6 kcal`
Also calculate the heat required to change `1g` of `C_("Diamond")` to `C_("Amorphous")`.

Explanation

Given
`{:(C_(D)+O_(2)rarrCO_(2)(g),DeltaH =-94.3 kcal ...(i)),(C_(A)+O_(2)rarrCO_(2)(g),DeltaH =97.6 kcal...(ii)),(ul("- - - + ")):}`
Subtracting equation (ii) from equation (i),
`C_(D) -C_(A) rarr O, DeltaH = +3.3`
or `C_(D) rarr C_(A) , DeltaH =+3.3 kcal`
i.e. heta of transition for `C_(D) rarr C_(A) =+3.3 kcal`
Also `12g C_(D)` changes to `C_(A)` with heat change `=+3.3 kcal`
`:. 1g of C_(D)` change to `C_(A)` with heat change
`= +3.3//12 kcla = 0.275 kcal`