Calculate ΔG° for the process: C (diamond) → C (graphite)

Question

a. Calculate ΔG° for the process: C (diamond) → C (graphite)

b. Is the formation of graphite favored? If so, why is it that the diamonds in a diamond ring do not become graphite no matter how long you watch them?

Answer 1

Hello Danny, to answer your question, we can look up the delta G values for diamond = +2.9kJ/mol and graphite = 0 kJ/mol. We would then set the equation as delta G = 0 - 2.9 = -2.9 kJ/mol. A negative change in delta g means that the change from diamond is thermodynamically favored. So why doesn't a diamond turn into graphite? If we look at the atom arrangement of diamonds, we would see a very tight rigid structure. Changing diamond into graphite would require breaking these bonds; however, would take a huge amount of energy to break. This means that the activation energy for this reaction is VERY HIGH. Hope this helps, thank you.