南昌大学2014上半年材料热力学重点题(附氧势.doc

部分答案不全，部分答案有错；不全的自行脑补，有错的自行更正，学长只能帮你们到这了solution:Solution：,exothermic reaction For the reaction : Solution: (a) When the equilibrium is reached, T = 500C = 773K(a) at T=300C=573K, Although the equilibrium PO2 is very low, kinetically the reaction is not favoured and reaction speed is very slow. So 300C is not suitable at At T=800C=1073K, lnPO2 =-22.2, PO2 =2.2810-10 atm. At 800C, if the equilibrium is reached, nitrogen can be of high purity level. However, at this high temperature , particles of Cu will weld together to reduce effective work surface. So it is not suitable to use this high temperature in purification either.(c ) The equilibrium oxygen pressure remains the same when the total pressure increases, which means a higher purity level of N2 .Solution: N2 =2N, H2 = 2H ， For N2 dissolving : For H2 dissolving：（a）For dissolving N2, PN2 = 1 atm, N=35cm3/100g melt, similarly: H =24.75cm3/100g melttotal gas : HN = 49.5 cm3/100g melt(b) H =24.75 cm3/100g melt (c ) HN = N(0.33)1/2 /1+H(0.33)1/2 /1=20.10+20.10 = 40.2cm3/100g meltSolution：（1）0.2 （2） （3）Solution:(a) (b)(c) Solution:(b) (c)答案更正为：TemperaturePhaseCompositionFraction1300Liquid6061.5838.59901000+Liquid7050.8949.29801000-Liquid_0763.79836.3Solution: SolutionSolution：SolutionSolution:solution: Solution: Solution: (a) At 0C, DG =0, TmDS = DH (b) At 0C, DG =0 a reversible process can be designed as follows to do the calculation: Ice, 0Cwater, 0Cwater, -5Cice, -5C（1）（2）（3）（4） （d） Solution: (a) (b) No, diamond is not thermodynamically stable relative to graphite at 298K.(c ) (c ) Assuming N atm , DG = 0, reversible processes as following can be designed to realize this,graphite, 298K,1atm（1）（4）（2）graphite, 298K, N atmdiamond, 298K, N atmdiamond, 298K,1atm(3)Solution: (a) Ag2O = 1/2O2 + 2Ag when Ag2O begins to decompose, (a) in pure oxygen at 1 atm, RTlnPO2 = 030514-66.044T = 0T = 462K(b) in air at Ptotal = =1 atm , PO2 =0.21ie. 30514- 66.044T + RTln0.21 = 0 T = 386K Solution: (a) Plot .At T=1000K, lnKa =8.01, Ka = 3010 (b)So the atmosphere will oxidize Ni.Solution: Solution:(1)(2)(3)(4)(5)c.d.e.Solution:ThestandardGibbsfreeenergychangeforreactionI:a.b.c. ;Niisstableunderthiscondition,andNiOisnotstable;d.e。fromthecalculation,wefoundthatat1000C.Soat1000C,whenthe oxygenpressureislessthan 3.461058Pa,Niisstableandcannotbeoxidized,andNiOwillbereducedtoNiunderthiscondi