5HC - Chemical Engineering Thermodynamics - October 1998

Part A (20 x 2 = 40 Marks) Answer All Questions

  1. Define heat capacity. Is it path function?
  2. Write two equation of state for a real fluid
  3. What is the criteria of equilibrium in terms of fugacity?
  4. Write Margules equation and its significance
  5. Explain theoretical flame temperature
  6. Define activity
  7. What is an adiabatic process? Write the expression for work done during reversible adiabatic process
  8. Explain thermodynamic state
  9. Explain excess function
  10. What are the various liquefaction processes?
  11. Explain Hess law of heat summation
  12. Define system and surroundings
  13. What is volumetric efficiency?
  14. What is the effect of inerts on equilibrium conversion?
  15. What is partial molal property?
  16. Define equilibrium constant
  17. State Zeroth law of thermodynamics
  18. Explain maximum boiling azeotropes
  19. Define net value and gross value of heat of combustion
  20. What is Joule-Thomson effect?
  21. Part B (5 x 12 = 60 Marks)

  22. (a) 220 kg of CO2 gas at 27oC and 1 atm is compressed adiabatically to 1/5th of its volume. It is then cooled to its original temperature. Find DQ, DU and W for each step and for the entire process


    (b) Derive Vander Waals equation of state

    (c) Derive an expression for the efficiency of Carnot cycle and show it is independent of the working fluid

  23. (a) Explain with a schematic diagram the working of an absorption refrigeration system

    (b) A triple stage compressor takes air at the rate of 5 kg/min at 150 kPa and 298 K and delivers at a pressure of 6000 kPa. If the index of compression is 1.3, what is the minimum driving power required if the mechanical efficiency is 80%.


    (c) 1 kmol of methane is stored in a container of 0.12 m3 volume. What is the pressure using

    (i) Ideal gas law (ii) Redlich-Kwong equation (iii) Vander Waals equation.

    Given Z = 0.83, Pc = 46 bar, Tc = 190 K

    (d) A Carnot refrigerator is used to maintain a space at 0oC while the outside temperature is 25oC. Find the C.O.P., mass of refrigerant required and power required if the capacity is one ton.

  24. (a) Derive Maxwell Relations


    (b) (i) Write a brief note on prediction of activity coefficients for binary system

    (ii) Prove: ( CP/ P)T = -T( 2V/ T2)P

  25. (a) Derive the Gibbs-Duhem equation from fundamentals

    (b) X-Y form azeotrope at 25oC containing 80% 'X'. Find Van Laar consatants. The vapor pressure of 'X' and 'Y' at 25oC is 700 and 710 mm Hg. Total pressure is 760 mm Hg. What is the composition of a vapor in equilibrium with liquid conatining 30% 'X'.


    (c) How will you use the correlatory methods to check whether the vapor liquid equilibrium data, say, for a binary system determined experimentally are accurate? (8)

    (d) Write a short note on Wilson equation (4)

  26. (a) Write the effect of temperature on equilibrium constant

    (b) For a reaction A Û 2B, the equilibrium constant at 500oC is 0.3. The standard heat of reaction is 500 kCal/kmol. Calculate, making suitable assumptions, the equilibrium constant at 200oC.


    (c) What are the criteria of phase equilibrium

    (d) What are homogeneous and heterogeneous chemical reactions? Explain them with suitable examples.