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VLE please help

  1. Oct 21, 2008 #1
    (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?
     
  2. jcsd
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