19. The metal tin undergoes a transition from a gray phase to a white phase at 286 K and atmospheric pressure. Given that the enthalpy change of this transition is 2090 J/mol and that the volume change of this transition is -4.35 cm/mol, estimate the temperature at which this transition occurs at 100 bar. 20. The following data are available for thermodynamic properties of graphite and diamond: Property Graphite Diamond G(T=298 K, latm), J/mol 2900 S(T=298 K), J/mol K 5.74 2.377 Density, kg/m 2220 3510 Assuming that the entropies and densities are approximately independent of temperature and pressure, (a) determine the pressure at which diamonds can be produced from graphite at 298 K and 350 K. (b) What is the minimum pressure at which diamonds can be produced from graphite?