Chapter 18.7, Problem 2.1ACP

The decomposition of diamond to graphite [C(diamond) → C(graphite)] is thermodynamically favored, but occurs slowly at room temperature.

1. a. Use Δ_fG° values from Appendix L to calculate Δ_rG° and K_eq for the reaction under standard conditions and 298.15 K.
2. b. Use Δ_fH° and S° values from Appendix L to estimate Δ_rG° and K_eq for the reaction at 1000 K. Assume that enthalpy and entropy values are valid at these temperatures. Does heating shift the equilibrium toward the formation of diamond or graphite?
3. c. Why is the formation of diamond favored at high pressures?
4. d. The phase diagram shows that diamond is thermodynamically favored over graphite at 20,000 atmospheres pressure (about 2 GPa) at room temperature. Why is this conversion actually done at much higher temperatures and pressures?