## Transcribed Text

(1) I recommend you do this problem by hand. Vapor pressures of benzene(1) and ethylbenzene(2) are given by:
benzene: ln P1sat(kPa) = 13.8594 - 2773.78/(t + 220.07) ethylbenzene: ln P2sat(kPa) = 14.0045 - 3279.47/(t + 213.20) where t is in centigrade. Assuming Raoult's law, calculate:
(a) (b) (c) (d)
(2)
P and y1 for x1 = 0.6 and t = 80 oC P and x1 for y1 = 0.6 and t = 80 oC t and y1 for x1 = 0.6 and P = 90 kPa t and x1 for y1 = 0.6 and P = 90 kPa
Vapor pressures of ethyl acetate(1) and isopropyl acetate(2) log10 P1sat(torr) = 7.25970 - 1369.41/(t + 235.475)
log10 P2sat(torr) = 7.33395 - 1436.53/(t + 233.665)
where t is in degrees centigrade.
are given by:
(a)
fractions corresponding to x1 = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0 where component 1 is ethyl acetate. Assume Raoult's law is valid.
(b) Plot your results as smooth curves on a T-x-y diagram.
(c) Experimental data for this system (Nishi, J. Chem. Eng. Japan 5, 334, 1972) are given
At a total pressure of 760 torr, calculate the equilibrium temperatures and vapor phase mole
below. Plot these as discrete points on the same paper used for part (b). reasonable for this system?
VLE of ethyl acetate(1) - isopropyl acetate(2) at 760 torr:
x1 y1 t(0C) .000 .000 88.92 .100 .140 87.5 .200 .263 86.1 .300 .380 84.9 .400 .494 83.7 .500 .593 82.6 .600 .673 81.5 .700 .760 80.4 .800 .842 79.3 .900 .927 78.2
1.000 1.000 77.26
Is Raoult's law
Chem Eng Thermo HW #4 Due Thursday, March 2
(3) At 277.59 K, the vapor pressure of ethane is 26.55 bars and the vapor pressure of propylene is 6.65 bars. Calculate pressure and vapor phase mole fractions at 277.59 K for each of the experimental liquid phase compositions x1 given below. Use:
(a) Raoult's law
(b) The ideal solution approximation but not the low pressure assumption:
φiyiP = xiPisatφisat exp(ViLsat[P - Pisat]/RT) Supplemental data at 277.59 K for part (b):
ethane: B = -216 cm3/mol VL propylene: B = -403 cm3/mol VL
(i=1,2)
= 77.2 cm3/mol = 78.0cm3/mol
(c) Plot your calculations as smooth curves on a P-x-y diagram. Use dashed curves for part(a) and solid curves for part(b). Also, plot the experimental data given below for this system as discrete points on the same diagram:
(d) Discuss the ability of each model to represent the experimental data.
Vapor-Liquid equilibria at 277.59 K for ethane(1) - propylene(2) (Sage and Lacey, Am. Petrol. Inst., Project 37, 1955)
x1 y1 0.0 0.0 0.209 0.452 0.390 0.646 0.568 0.775 0.739 0.873 0.896 0.951 1.0 1.0
P(bar) 6.65 10.34 13.79 17.24 20.68 24.13 26.55
(4) At 308.15 K, the vapor pressure of chloroform is 296.6 torr and the vapor pressure of methanol is 209.7 torr.
(a) Assuming Raoult's law is valid, calculate y1 and P at 308.15 K for x1 values of 0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5,0.6, 0.7,0.8, 0.9, 0.95 and 1.0. (1=chloroform, 2=methanol)
(b) Plot your calculated results on a P-x-y diagram as smooth curves.
(c) Experimental data for this system (Kireev et al., Zh. Fiz. Khim. 15, 492, 1941) are given
below. Plot these data as points on the same paper used for part (b). model for this system? Why or why not?
VLE data for chloroform(1) - methanol(2) at 308.15 K
Is Raoult's law a good
x1
y1
.000 .050 .100 .200 .300 .400 .500 .600 .700 .800 .900 .950 1.000
P(torr)
.000 209.7 .143 230.3 .263 253.3 .431 295.6 .539 328.9 .610 350.6 .654 362.5 .684 366.7 .704 368.9 .724 366.5 .776 355.2 .845 340.0 1.000 296.6

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