CHEMICAL AND BIO-THERMODYNAMICS Question Papers (Supple, 2007 Nov, RR)

SET :1

1. A gas is confined in a cylinder by a piston, 2 in. in diameter, on which rests a “weight”. The mass of the piston and weight together is 8 lbm. The local acceleration of gravity is 32.00 ft/sec2. Assume standard atmospheric pressure.
(a) What is the force exerted on the gas by the atmosphere, the piston, and the weight in pounds force, assuming no friction between the piston and cylinder?
(b) What is the pressure of the gas in pounds force per square inch?
(c) If the gas in the cylinder is heated, it will expand, pushing the piston and weight upward. Assuming that enough heat is supplied to raise the piston and weight 8 in., calculate the work done by the gas in raising the piston and weight. What is the change in potential energy of the piston and weight? Give your answers in foot-pounds force. [4+4+8]

2. A power-plant cycle is an follows:
(a) Saturated liquid water from the condenser at 5 psig in pumped into a boiler operating at 175 psia. [8]
(b) The steam leaves the boiler superheated 1500F.
i. Assuming the condenser and boiler pressures are constant, calculate the maximum efficiency of the cycle (i.e. for a reversible adiabatic turbine).
ii. For comparison calculate the efficiency of a Carnot cycle operating between the saturation temperature at the boiler and the condenser pressures. Make the same calculation for the Carnot engine absorbing heat at the temperature of the steam leaving the boiler and discarding heat at the saturation temperature in the condenser.
iii. Calculate the efficiency of the cycle if the turbine operates adiabatically but irreversably in such a way that the actual ΔH is 0.9 of the isentropic ΔH. [2+3+3]

3. Water at 450C and 10 kPa enters an adiabatic pump and is discharged at a pressure of 8600 kPa. Assume the pump efficiency to be 75%. Calculate the work of the pump, the temperature change of the water and the entropy change of the water. Saturated liquid water properties at 450C are : V = 1, 010cm3kg−1, β = 425x10−6K−1and CP = 4.178kJkg−1K−1 [4+12]

4. (a) Write Gibbs / Duhem equation.
(b) A laboratory needs to use 2,000 cm3 of an antifreeze consisting of 30 mole percent solution of methanol in water. What volumes of pure methanol and pure water at 25 0C must be mixed to form 2,000 cm3 of antifreeze, also at 250C? Partial molar volumes for methanol and water in 30 mole percent methanol solution at 250C are: for methanol 38.632 cm3mol−1 and for water
17.765 cm3mol−1. For pure species the volumes are: 40.727cm3mol−1 for methanol and 18.068cm3mol−1 for water. [8+8]

5. Explain in detail about Raoult?s law. [6+10]

6. Consider a vessel which initially contains only n0 mol of water vapour .If decom-
position occurs according to the reaction.
H2O → H2 + 1/2O2
Find expression which relate the number of moles and the mole fraction of each chemical species to the reaction co-ordinate ε [4+12]

7. Discuss in detail about product formation. [4+12]

8. How Degree of reduction of substrate,biomass and product can be calculated. [5+5+6]


SET :2

1. Explain the formulation of the first law of Thermodynamics and illustrate any two
examples. [8+8]

2. A refrigeration machine requires 1 kw of power per ton of refrigeration.
(a) What is the co-efficient of performance?
(b) How much heat is rejected to the condenser?
(c) If the condenser operates at 600F, what is the lowest temperature the refrigerator could possibly maintain, assuming that the heat load is always 200 Btu/min? [5+5+6]

3. With help of Maxwell’s equation prove that the specific heats of ideal gases are functions of temperature only. [6+10]

4. (a) Define chemical potential and write the general equation for Gibbs energy interms of temperature pressure and chemical potential.
(b) By definition, the partial molar volume is: Vi= [∂(nV)/∂ni]P,T, nj. What physical interpretation can be given to this equation? [8+8]

5. Explain Formulation of vapour liquid equilibrium. [4+12]

6. Consider a vessel which initially contains only n0 mol of water vapour .If decomposition occurs according to the reaction.
H2O ! H2 + 1/2O2
Find expression which relate the number of moles and the mole fraction of each chemical species to the reaction co-ordinate ε [4+12]

7. (a) Explain the Gaden classification from stoichiometric point of view the product formation in fermentation processes.
(b) The following stoichiometric equation describes penicillin systhesis

1.5Glucose+H2SO4+2NH3 + phenyl acetate ----> Pencillium G + CO2+8H2O

the theoretical yield of pencillium is 1.2g/(gram of glucose). Find out the molecular weight of pencillium G. [8+8]

8. (a) Define the “Yield Coefficient”and explain its significance in the growth of cells by substrate utilization
(b) The following is the stoichiometric equation for combustion of the cell Pseudomonas fluorescens growing in glucose medium.

CH1.66N0.2O0.27 + 1.28O2 ! CO2 + 0.1N2 + 0.83H2O

Assuming the heat of combustion of 104 kcal per moleO2, calculate the heat released by combustion of bacteria in k cal/gram. [8+8]


SET :3

1. Explain the formulation of the first law of Thermodynamics and illustrate any two
examples. [8+8]

2. A power-plant cycle is an follows:
(a) Saturated liquid water from the condenser at 5 psig in pumped into a boiler
operating at 175 psia. [8]
(b) The steam leaves the boiler superheated 1500F.
i. Assuming the condenser and boiler pressures are constant, calculate the maximum efficiency of the cycle (i.e. for a reversible adiabatic turbine).
ii. For comparison calculate the efficiency of a Carnot cycle operating between the saturation temperature at the boiler and the condenser pressures. Make the same calculation for the Carnot engine absorbing heat at the temperature of the steam leaving the boiler and discarding heat at the saturation temperature in the condenser.
iii. Calculate the efficiency of the cycle if the turbine operates adiabatically but irreversibly in such a way that the actual ΔH is 0.9 of the isenotropic ΔH. [2+3+3]

3. Water at 450C and 10 kPa enters an adiabatic pump and is discharged at a pressure of 8600 kPa. Assume the pump efficiency to be 75%. Calculate the work of the pump, the temperature change of the water and the entropy change of the water. Saturated liquid water properties at 450C are : V = 1, 010cm3kg−1, β = 425x10−6K−1and CP = 4.178kJkg−1K−1 [4+12]

4. (a) Describe the important characteristics of an ideal gas mixture and write Gibb’s theorem.
(b) Derive the property equations describing the ideal gas behavior of mixtures. [8+8]

5. Discuss in detail about Solid/liquid Equilibrium. [8+8]

6. Determine the number of degrees of freedom F for each of the following systems.
(a) A system of two miscible Non reacting species which exists as an azeotrope in vapour/liquid equilibrium.
(b) A system prepared by partially decomposing CaCo3 into an evacuated space.
(c) A system prepared by partially decomposing NH4Cl into an evacuated space.
(d) A system consisting of the gases CO, CO2, H2, H2O, and CH4 in chemical equilibrium. [4+4+4+4]

7. (a) Explain the Gaden classification from stoichiometric point of view the product
formation in fermentation processes.
(b) The following stoichiometric equation describes penicillin systhesis

1.5Glucose+H2SO4+2NH3 + phenyl acetate→ Pencillium G + CO2+8H2O

the theoretical yield of pencillium is 1.2g/(gram of glucose). Find out the molecular weight of pencillium G. [8+8]

8. Discuss in detail that electrons in the organic substrate is transferred to oxygen. [4+12]


SET :4
1. (a) Write about the thermodynamic state and state functions.
(b) Write about the steady - state flow process. [8+8]
2. A vapor-compression refrigeration machine is to be used in an oil refinery to cool a solvent stream to 400F. The cycle will be conventional expect that a counter-current heat exchanger will be installed to sub cool the liquid from the condenser with the vapor stream from the refrigerator coils. Ammonia is to be the refrigerant, and the heat load in the refrigerator coils is 200,000 Btu/min. The refrigerant is to evaporate at 320F and liquefy in the condenser at 900F. The compressor will be adiabatic in its operation and be 80 percent efficient compared with isentropic operation. The minimum temperature difference that can be attained in the exchanger is 100F. What is the power requirement of the compressor? How does this result compare with the power of a conventional vapor-compression machine without the exchanger? Also compare the circulation rates for the two cases. [5+11]

3. (a) Write fundamental property relationships for U, H, A (Helmholtz energy) and G
(b) Write the Maxwell’s equations. [8+8]

4. Estimate the fugacity of the Cyclopentane at 1100C and 275 bar. At 1100c the vapor pressure of cyclopentane is 5.267 bar. [16]

5. Explain in detail about Raoult?s law. [6+10]

6. Consider a vessel which initially contains only n0 mol of water vapour .If decomposition occurs according to the reaction.
H2O ---> H2 + 1/2O2
Find expression which relate the number of moles and the mole fraction of each chemical species to the reaction co-ordinate ε [4+12]

7. How EMP pathway related to cell wall components. [6+10]

8. Discuss theoretical predictions of yield coeffiecients. [6+10]