Diamond and graphite are two crystalline forms of carbon. At 1 atm and 25°C, diamond changes to graphite so slowly that the enthalpy change of the process must be obtained indirectly. Determine ΔHrxn for
C(diamond) → C(graphite)
with equations from the following list:
(1) C(diamond) + O2(g) → CO2(g) ΔH = −395.4 kJ
(2) 2 CO2(g) → 2 CO(g) + O2(g) ΔH = 566.0 kJ
(3) C(graphite) + O2(g) → CO2(g) ΔH = −393.5 kJ
(4) 2 CO(g) → C(graphite) + CO2(g) ΔH = −172.5 kJ