7-8 8 a Problem 3 Pure plutonium forma six different equilibrium solids at atmospheric pressure. The room tem. perature equilibrium phase, 8, is monoclinic. Transition (phase 1 + phase 2) A7 (Caly 7pm ("C) mole B 0.8 122 B 0.15 205 0.13 318 0.02 451 liquid 0.44 476 The standard enthalpy of formation (ie, the zero of the enthalpy scale of Pu at STP) is HT = 298K, P = latm) = 0 and the entropy at STP is 3(T = 298K, P = latm) = 13.2cal/"mole. The molar heat capacities are given by plase of Pu C (cal/"mole) temperature range (*K) 5.91 +5.8 x 10-T 298-395 5.21 + 7.05 x 10-T395-480 7 2.98 +11.1 x 10T 480-588 8 588-753 8.4 753-913 liquid 8 913-The (a) Calculate the molar enthalpy of the most stable phase of Pu and plot it as a function of temperature from T = 298K to T = 1000K. (b) Calculate the molar entropy of the most stable phase of Pu and plot it as a function of temperature from T = 298K to T = 1000K. (c) Calculate the molar Gibbs free energy of all phases of Pu and plot it as a function of temperature from T = 298K to T = 1000K. (d) Plot the molar Gibbs free energy of all phases as a function of the molar enthalpy for temperatures from T = 298K to T - 1000K 9.0 e 3