Physical Chemistry Chapter 10 Nonideal Solutions
Chapter 10 Nonideal Solutions Physical Chemistry
Physical Chemistry Nonideal Solutions Models for Nonelectrolyte Activity Coefficients Simple solution RTInyiB =Wxc, RTInylc =WxB,(10.31 w depends on Tand p but not on the mole fractions let z be the number of nearest neighbors of each molecule in the array. The intermolecular-interaction energy is approximated as the sum of nearest-neighbor interactions If &BB, Eco, and aBc are the interaction energies for adjacent B-B, C-C, and B-c pairs, respectively The energy of mixing mixu=2Nalebc 2 BB+EcC/nBnc/(ng+ nc)=WnBnc/(nB+nc
Simple Solution Models for Nonelectrolyte Activity Coefficients Nonideal Solutions W depends on T and P but not on the mole fractions. let z be the number of nearest neighbors of each molecule in the array. The intermolecular-interaction energy is approximated as the sum of nearest-neighbor interactions. ( ) ] /( ) /( ) 2 1 [ mix A B C B B CC nB nC nB nC WnB nC nB nC U = zN − + + + ln , ln , 2 , 2 R T I,B = WxC R T I C = WxB (10.31) If BB, CC, and BC are the interaction energies for adjacent B-B, C-C, and B-C pairs, respectively. The energy of mixing Physical Chemistry
Physical Chemistry Nonideal Solutions Models for Nonelectrolyte Activity Coefficients where W=ENAEBC-(EBB+Ecc) For two liquids b and c whose molecules have similar sizes and shapes △ma≈0,SO△mH=△m2U E SOSE=△S-△ nUX mIX G=H-TS≈H=△AH=△U ux GE=nB CW(T P n+n
Nonideal Solutions where For two liquids B and C whose molecules have similar sizes and shapes, mixV 0, so mixH = mixU ( )] 2 1 [ A BC BB CC W zN − + , = − = 0 i d mix mix i d E mixS mixS so S S S G H TS H mixH mixU E E E E = − = = W (T, P) n n n n G B C E B C + = Models for Nonelectrolyte Activity Coefficients Physical Chemistry
Physical Chemistry Nonideal Solutions Models for Nonelectrolyte Activity Coefficients G C-W(T,P) PStn aGE RT yii an, )T,P, lj# (Problem 10.4 simple solution model RTInyig=Wxc, RTInyic=WxB,(10.31 Redlich-Kister equation Margules equation) G n+n =xBxCRT[A4+A2(x2-xc)+A3(x2-xc)2+…+A(x2-xc)" (103)
Nonideal Solutions T P n j i i E I i n G RT = , , , ln simple solution model (10.32) (Problem 10.4) W (T, P) n n n n G B C E B C + = Models for Nonelectrolyte Activity Coefficients [ ( ) ( ) ( ) ] 2 1 1 2 3 − = + − + − + + − + n B C B C B C n B C B C E E m x x RT A A x x A x x A x x n n G G Redlich-Kister equation (Margules equation) Physical Chemistry ln , ln , 2 , 2 R T I,B = WxC R T I C = WxB (10.31)
Physical Chemistry Nonideal Solutions Models for Nonelectrolyte Activity Coefficients Redlich-Kister equation Margules equation) E G E n+r x3xR0+A1(x1-x)+4(x2-xc)2+…+41(x2-x)y (10.32 B C w(T, P) simple solution model n+n
Nonideal Solutions simple solution model (10.32) Models for Nonelectrolyte Activity Coefficients [ ( ) ( ) ( ) ] 2 1 1 2 3 − = + − + − + + − + n B C B C B C n B C B C E E m x x RT A A x x A x x A x x n n G G Redlich-Kister equation (Margules equation) W (T, P) n n n n G B C E B C + = Physical Chemistry