1. Oct 21, 2008

coso21

(a) Find the dew temperature and composition for a mixture of y1 = 0.55 at 3.954 bar. (Answers. 371 K and x1 = 0.58)
(b) Find the bubble temperature and composition for a mixture of x1 = 0.50 at 3.954 bar.
(Answers. 371 K and y1 = 0.49)
(c) Using the Wilson equation and the constants listed, find the bubble pressure and vapour composition for a mixture of 30 mol% methyl acetate at 90C.
(Answers. 3.1 bar and y1 = 0.36)

Vc zcPc, bar Tc, K
Methyl acetate (1) 46.3 506.8 0.324 228.0 cc/mol 0.254
Methanol (2) 79.9 512.6 0.559 118.0 cc/mol 0.224

Antoine Constants (P is in torr)
CA B C Range,
Methyl acetate (1) 7.41791 1386.510 247.853 57 - 205
Methanol (2) 7.97010 1521.230 233.970 65 - 214

Constants A12 A21
Margules’ 0.8427 0.4043
Van Laar 0.8914 0.4718
Wilson 336.148 350.841

Vapour-Liquid Equilibrium Data at 3.954 bar Total Pressure,
Methyl acetate – Methanol
C x1Temperature, y1
104.40 0.0000 0.0000
100.50 0.0880 0.1540
98.60 0.1980 0.2730
97.30 0.2960 0.3680
97.20 0.3980 0.4370
97.10 0.5150 05220
97.00 0.5380 0.5380
97.30 0.6260 0.5980
98.10 0.7320 0.6840
98.90 0.7970 0.7500
99.60 0.8340 0.7950
101.30 0.9130 0.8950
103.80 1.0000 1.0000

How would i solve each question? I can't get the right answer.
I used Raoult's Law for the first two and didnt get close, is that right?

I need to use the antoine equation to find P1sat and P2sat right? But I don't know what value for Temperature I am meant to put in the equation (T is in celsius).

What do I use after I have worked that out?