1表1-18求K的有关数据w [C] /%T/K项目0.20.40.60.81.0726Pio/Peoz107.4241.2396.6566.4K27081833537603661726lgk;2.732.782.822. 852.86Po/peo2170.2373.2600876.21202Ks9331202193385110001095.3leki2.933. 042.9733. 08pon/pco2565.2929.4267.6K1338141315492033Igk:3.133.153. 19-以lgK-w【C],关系作图(图1-10),由图中直线得到各温度的lgx,如表1-19所示。表1-19各温度的lgk1833T/K19332033(1/T)×1045.465. 174.92Igks2. 702.903. 09再用回归分析法处理,可得3.22033K7192Igke+ 6. 63T1933K3.0而S1833K71922.8A,C(2)= -RTInk=-19.147T1g(+ 6. 632.65137705127TJ-mol-0.20.40.60.810w[Cy%故AG=166550-171T-(137705127T)图1-10IgKi-w[C】图28845-44TJ·mol-l1-1-22试计算下列反应的A,G及IgK的温度关系式:CO,+[C]一2CO;(FeO)[Fe]+[O];[Ti] +[C]=--TiIC(s)。解(1)-2COA,G(1)CO,+C(石)-AGec(石) [C]CO, +[C]2COA,G=A.G(1)-AGA,C=2A,C(CO)-A,C(CO,)-AGe=2×(-114400-85.77T)-(-3953500.54T)-(22590-42.26T)=143960-128.74TJ·mol-!143960128.747519Igke = -+ 6.7219.147T19.147T· 16 :
(2)FeO(1) Fe(1) +-A,G(FeO)FeO(1) —(FeO)AGroFe(1) [Fe]AGPeAGO20,—(0)A,C(FeO)[Fe] +[0]A,C =-A,(FeO) - ACeo + ACF + AC=-(-256060+53.68T)-0+0+(-1171502.89T)=138910 56.57T J·mol-56.571389107257Igkm+ 2.9819.147T+19.1472(3)Ti(s)+ C(石)TiC(s)A,G(TiC)ACHTi(s) —[Ti]ACec(石)一[c]A,Ge[Ti] +[C] -TiC(s)A,G=A,G(TiC)-AG-AGe=-184800+12.55T-(25100-44.98T)-(22590-42.26T)=~232490 +99.79T J·mol23249099.79=121425.21Igk19.147T19.147T1-1-23在1873K时,铁液中【Si]为0,氧化:【Si]+0,一SiO,(s),铁液中硅的x[Si]=0.2,s=0.03,Po=100kPa。试计算硅氧化反应的A,G。硅的标准态分别为:(1)纯液硅;(2)假想纯液硅;(3)质量1%溶液。%=0.0013。解[Si] + 0, -sio,(s)A.G, = A,C - RTlnasiPo.当【Si]采用不同标准态时,4,G和as有不同的数值。为计算4,G.,需要先计算出各标准态的A,G及其相应的as。反应的A,C由下列反应组合求出A,G(Si02,s)Si(1) + 0, Si0,(s)AGSsi(1) [Si][Si] + 0, Sio,(s)A,C-A,G(Si02,5)-AC而A,C(SiO,,5)=-946350+197.64TJ·mol-(1)纯液硅标准态:as(R)=0.2×0.03= 0.006,AC%= 0A,G=A,G-RTInast=[A,C(SiO,,s)-AG] -RTnas=[-946350+197.64T-0]-19.147TIg0.006= 946350 +(197.64T+42.54)×1873=-946350+449857=-496492J·mol-17
(2)质量1%溶液标准态:55.85(108 28 0. 003) = 231asi(%)=asitAG=-131500-17.61TA,G。=[946350+197.64T-(-131500-17.61T)】 -19.147TIg231=-814850+215.25T45.26T=814850+(215.25-45.26)×1873=-496458J-mol-1(3)假想纯液硅标准态:s(R) - 6 ×10-4.62s(8) =-0.0013而AGs = RTIny = RTIn0. 00134,G=[946350+197.64T(19.147TIg0.0013)]19.147TIg4.62=-946350+(197.64+55.26)T-12.72T= 946350 + 240. 18 × 1873 = 496493J·mol-由上述计算可知,组分活度的标准态不同,则,G不同,但由此不同标准态计算的A,G则是相同的。1.2增补习题及解答1-2-1利用下列固体电解池电池:Pr-Rh|Fe(s), FeO-Al,O,(s),Al,O,(s) /ZrO, +(CaO)/Mo0,(s), Mo(s) iPt-Rh31280测得反应:Fe(s)+-0,+Al,O,(s)Fe0.Al,0,(s)的lgpo,+10.00(1373T1700K)。试求:(1)复合化合物Fe0·Al,0,(s)的4,G;(2)1600K,上述固体电解池电池的电动势。解(1)A,G(FeO·Al,Os,s)Fe(s) + -电池反应:0, + Al,0,(s) Fe0.Al,0,(s)则A,G(Fe0.Al,O,s) = A,G+A,G(Al,0,,s)而) = 19. 147 ×0.57(~ 31280 + 10. 00)A,C =-RTIn(=-299459+95.74TJ·mol-又A,G(Al,O,8) = -1687200+323.24T J-mol-故A,G(Fe0·Al,0,,s)=-299459+95.74T+(-1687200+323.24T)-1986656+418.98TJ·mol-1(2)1600K电池的电动势。电极及电池的反应:Mo0(8)+2eMo(s) + 02正极:2-18
负极:Fe(s)+Al,0,(s)+02-Fe0-Al,0, +2e→Mo(s) +FeO.Al,O,(s)电池反应:Fe(s)+Al,0,(s)+Moo,而A,C=-2EF即2EF=-A,G=-[A,G(FeOAl,0,,s)-A,G(Al,O,,s)--A,C(Mo0,,s))=1986656-418.98T+(-1687200+323.24T)+ 578200 + 166. 5T)=10356 +12.49TE -1036 1348×1600= 0.172V故2×965001-2-2钒溶于铁液中形成正规溶液。试求w[V]=30%,P=100kPa及温度为1600℃时,反应的4,G(VN,s,1873K)。溶解钒的%%=0.1,钒的标准态为(1)纯物质;(2)质量1%溶液。[V] +解VN(s)形成反应为-VN (s)-N.A,C=-RTInK-RTIn(!-), Px, = 1A,C - -RTIn (1/vx [V])纯物质标准态:质量1%溶液标准态:A,G=-RTIn(1/f[V])。因此,计算反应的A,C,在于求出两种标准态的活度系数:及fv。v:由于Fe-V系是正规溶液模型,由下式Inyv = a(I -x[ vl)?RT式中,α为正规溶液的混合能参量,是与温度及浓度无关的常数。可得RTInyyRTInyα(I -x[VJ)1当×[V]-0时,In—In%,故品=lnyRT而Inyy = ln(1 - a[vi)?w[V]/My又w[V] = 30% , x[V] =w[V],/M,+(100 - m(V].)/M,30/5130/51 +(10030) = 0.319故In = 1ny(1 - x[V])2 = - 2. 30 × (1 - 0.319) = ~ 1. 067所以v= 0.344=-0.344又= 3.440. 1Yv(1)纯物质标准态的A,G%A,G=-RTIn= - 19. 147 × 1873g[-34415J·mol-YxV0.344x.0.319.19
(2)质量1%溶液标准态的A,GA,Ge=-RTIn=-19.147×18731g=72215J·mol-.44×30fwlVi.1-2-3钛在铁液(1600℃)中的r=0.011。试求同样温度下,以质量1%溶液为标准态的钛的活度系数fn。解这是两种标准态活度系数的转换关系:YT =YnfhfrY故YT为此,需求出%。由Mr.MeACg = RTIn 00M.=RTIny+RTIn100M而Ti(s)=[Ti]:AG=-40580-37.03T55.8540580 37.03 ×1873 =19.147 ×1873g% +19.147 ×187314-109737=358621g-693661g% = -109737 + 69366= - 1. 1235862%= 0.0770.011故= 0.143fr.=0.0771-2-4铁液中w[V]=0.08%,求反应:2[V】+1.50,-V,0,(s)在1873K的平衡常数K及po=100kPa的△,G,及平衡氧分压。已知%=0.1。解(1)[V]以纯物质为标准态:上述反应的A,C和反应2V(s)+1.50,—V,0(s)的4,G相同,故可用此反应的A,G进行相关的计算。1) k:2V(s) +1. 50, —V,0,(s);A,C=-1202900+237.531202900237.53= 21.137Igk=19.147×187319.147K = 1.37 × 102lav,o2) ,G :A,G. = A,c + 19. 147TIgaupo,式中ave,V,0,(s)为纯固相,以纯物质为标准态时,ave=1;钒在铁液中溶解度很低,属稀溶液浓度范围,以纯物质为标准态时,=%=ay0.1。0. 08 //0. 08100-0.08)又x[V] = 8. 77 × 10 **515155.85故ay = %x[V] = 0. 1 ×8. 77 ×10~ = 8. 77 ×10~5- 20