thermodynamics-old question papers- jntu

Code No: R05310803 Set No. 4
III B.Tech I Semester Regular Examinations, November 2007
CHEMICAL ENGINEERING THERMODYNAMICS-II
(Chemical Engineering)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
⋆ ⋆ ⋆ ⋆ ⋆
1. Water and a liquid mixture of propane and butane are admitted into a vaporizer at
50 oC and leave as vapors at 175 oC. The hourly 25 kg water, 350 kg propane and
550 kg of butane are admitted. Estimate the heat requirement in the vaporizer.
Component Latent heat of vaporization Boiling point a b×103 C×106
cal/gm mole at 100oC temp Tc
oC
Propane 5038 96.6 8.41 35.95 -6.97
Butane 6138 151.8 2.25 45.40 -8.83
Water 10388 96.6 7.14 2.64 0.046
Cp =a+bT+cT2 where Cp is in cal/mol.k and T is in K. Mention the assumption
made to solve the problem. [16]
2. (a) 40 kg of ethyl alcohol and 50 kg of acetic acid are charged into a reactor to
yield ethyl acetate as per the reaction,
C2H5OH (l) + CH3COOH (l) = C2H5OOCCH3 + H2O
The reaction is 60% complete. Estimate the heat eect of this process heat of
combustion in cal/mol: C2H5OH = -326700; CH3COOH = - 208300; C2H5OOCCH3
= - 538760, H2O(l)= - 68.3 Kcal/gm mole.
(b) Write short notes on eect of temperate on heat of reaction. [10+6]
3. (a) Estimate Z, HR and SR at 70 oC and 200Kpa for an equimolar vapor mixture
of propane and pentane using virial expansions B11 = -276, B22 = -809, B12
= -466 cm3/mol.
(b) Write and explain fundamental residual property relation. [10+6]
4. For Diethyl ether (1) - Chloroform (2) at 30 oC, γ
1 = 0.71 and γ
2 = 0.57, P1
sat =
33.73 kPa and P2
sat = 86.59 kPa. The system is believed to governed by Margules
type of equations for activity coecients. Prepare a p-x-y diagram for the system
at 30 oC. [16]
5. (a) Explain bubble print and dewprint.
(b) Describe the vapor/ liquid equilibrium calculation procedure for DEW P. Va-
por and liquid phases may be considered as non- ideal. [6+10]
6. Show that the residual Gibbs energy of fluids from Redlich-Kwong equation of state
is GR
RT = Z − 1 − ln(1 − h)Z −
Code No: R05310803 Set No. 4
8. For the gas phase reaction CO2 (g) + 2H2 (g) , CH3OH (g) at 10000 C and at
500 bar pressure,calculate the equilibrium composition using the following data:
K = 0.68 at 10000C; The fugacity coecients at this pressure:
CO2 =0.99; H2 = 1.15; CO = 1.08; H2O = 0.86. [16]