A study of the system, n-pentane (1) and propionaldehyde (2) at 40 degree C has

Question

A study of the system, n-pentane (1) and propionaldehyde (2) at 40 degree C has shown that gamma_1^infinity = 3.848 and that gamma_2^infinity = 3.979. At 40 degree C, the vapor pressure for n-pentane is 1.1541 bars and that for propionaldehyde is 0.7609 bars. This study also determined that the Margules equations for the activity coefficient do an adequate job of correlating the experimental data. Determine the total pressure and the vapor composition, y_1, above a liquid solution of 40 mole % n-pentane.

Explanation / Answer

Given Y1infinity= 3.848

lnY1(infinity )= 1.35 =A12 and lnY2(infinity)= 1.38 =A21

For Margules   equation, activity coefficients can be written as

lnY1= x22[A21x1+ 2(A21-A12)x1 ]

for x1=0.4 and x2= 1-x1= 0.6

lnY1= (0.6)2 [ 1.38*0.4 + 2*(1.38-1.35)*0.4]=0.207

Y1= 1.23

lnY2= x12[A21+ 2(A12-A21)x2 ] = (0.4)2[ 1.38+2*(1.35-1.38)*0.6]=0.00576

Y2= 1.005

P= x1Y1p1sat +x2Y2P2sat= 0.4*1.23*1.1541+0.6*0.761*1.005=1.027 bar

And y1= X1Y1P1sat/ P= 0.4*1.23*1.154/1.027=0.553

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.