chemical engineering thermodynamics for chemical chemical engineering Mcqs
1. Cp Cv = R is valid for ______________ gases?
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A. Very high pressure

B. Very low temperature

C. Ideal

D. All of the above

2. During Joule-Thomson expansion of gases_________________?
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A. Entropy remains constant

B. Temperature remains constant

C. None of these

D. Enthalpy remains constant
3. If two pure liquid constituents are mixed in any proportion to give an ideal solution, there is no change in____________________?
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A. Volume

B. Enthalpy

C. Both A. & B

D. Neither A. nor B

4. In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13C and 37C respectively, the Carnot COP will be________________?
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A. 0.168

B. 5.2

C. 6.2

D. Data insufficient, cant be found out

5. The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition?
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A. Gibbs free energy

B. Enthalpy

C. Internal energy

D. Helmholtz free energy

6. The minimum number of phases that can exist in a system is________________?
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A. 2

B. 1

C. 3

D. 0

7. Fugacity and pressure are numerically not equal for the gases__________________?
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A. At low temperature and high pressure

B. At standard state

C. Both A. and B

D. In ideal state

8. Which of the following is Virial equation of state ?
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A. None of these

B. PV = A + B/V + C/V2 + D/V3 +

C. PV = nRT

D. (p + a/V2)(V b) = nRT

9. The equilibrium constant for a chemical reaction at two different temperatures is given by__________________?
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A. Kp2/Kp1 = (1/R) (1/T2 1/T1)

B. Kp2/Kp1 = (?H/R) (1/T2 1/T1)

C. Kp2/Kp1 = (?H/R) (1/T2 1/T1)

D. Kp2/Kp1 = ?H (1/T2 1/T1)

10. The fugacity of a gas in a mixture is equal to the product of its mole fraction and its fugacity in the pure state at the total pressure of the mixture. This is__________________?
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A. Henrys law

B. The statement as per Gibbs-Helmholtz

C. None of these

D. Called Lewis-Randall rule
11. Solid and liquid phases of a substance are in equilibrium at the____________________?
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A. Critical temperature

B. Melting point

C. Freezing point

D. Both B. and C
12. In an ideal solution, the activity of a component equals its __________________?
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A. Partial pressure

B. Fugacity at the same temperature and pressure

C. None of these

D. Mole fraction
13. Specific ____________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.)?
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A. Entropy

B. Internal energy

C. Enthalpy

D. Gibbs free energy
14. A refrigeration cycle is the same as a _____________ cycle?
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A. Heat engine

B. Turbine

C. None of these

D. Reversed heat engine
15. Troutons ratio of ______________ liquids is calculated using Kistyakowsky equation?
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A. Polar

B. Non-polar

C. Both A. & B

D. Neither A. nor B

16. The expression for entropy change given by, ?S = nR ln (V2/V1) + nCv ln (T2/T1) is valid for ______________________?
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A. Simultaneous heating and expansion of an ideal gas

B. Heating of a substance

C. Reversible isothermal volume change

D. Cooling of a substance

17. The energy of activation of exothermic reaction is_________________?
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A. Negative

B. Not possible to predict

C. Very large compared to that for endothermic reaction

D. Zero

18. The standard Gibbs free energy change of a reaction depends on the equilibrium______________________?
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A. Pressure

B. Temperature

C. All A, B. and C

D. Composition

19. Which of the following is not an extensive property ?
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A. None of these

B. Entropy

C. Free energy

D. Refractive index
20. 1m3 of an ideal gas at 500 K and 1000 kPa expands reversibly to 5 times its initial volume in an insulated container. If the specific heat capacity (at constant pressure) of the gas is 21 J/mole . K, the final temperature will be ?
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A. 154 K

B. 274 K

C. 174 K

D. 35 K

21. For a thermodynamic system containing x chemical species, the maximum number of phases that can co-exist at equilibrium is_________________?
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A. x

B. x + 2

C. x + 1

D. x + 3

22. Which of the following is not a common refrigerant ?
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A. Ammonia

B. Ethylene

C. Freon-12

D. Carbon dioxide

23. Chemical potential (an intensive property) of a substance is a force that drives the chemical system to equilibrium and is equal to its partial molar properties. The ratio of chemical potential to free energy of a pure substance at constant temperature and pressure is________________?
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A. 1

B. ?

C. 0

D. None of these

24. Compressibility factor of a gas is___________________?
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A. Not a function of its temperature

B. Not a function of its pressure

C. Not a function of its nature

D. Unity, if it follows PV = nRT

25. Heat of formation of an element in its standard state is___________________?
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A. 0

B. 0

C. A function of pressure

26. Pick out the correct statement?
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A. Like internal energy and enthalpy, the absolute value of standard entropy for elementary substances is zero

B. The internal energy of an ideal gas depends only on its pressure

C. Maximum work is done under reversible conditions

D. Melting of ice involves increase in enthalpy and a decrease in randomness

27. For spontaneous changes in an isolated system (S = entropy) ___________________?
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A. ds > 0

B. ds = 0

C. ds = Constant

D. ds <0

28. The rate at which a substance reacts is proportional to its active mass and the rate of a chemical reaction is proportional to the product of active masses of the reacting substances. This is the_________________?
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A. Statement of Vant Hoff Equation

B. None of these

C. Lewis-Randall rule

D. Le-Chateliers principle

29. Which of the following is affected by the temperature ?
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A. Free energy

B. All A, B. & C

C. Activity co-efficient

D. Fugacity

30. At a given temperature, the volume of a gas dissolved in a solvent _______________ with increase in pressure?
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A. May increase or decrease; depends on the gas

B. Decreases

C. Remains unchanged

D. Increases

31. The absolute entropy for all crystalline substances at absolute zero temperature is ____________________?
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A. Zero

B. Indeterminate

C. More than zero

D. Negative

32. A refrigerator works on the principle of _____________ law of thermodynamics?
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A. Zeroth

B. First

C. Second

D. Third

33. Enthalpy of a gas depends upon its___________________?
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A. Volume

B. Mass

C. Temperature

D. Pressure

34. A cyclic engine exchanges heat with two reservoirs maintained at 100 and 300C respectively. The maximum work (in J) that can be obtained from 1000 J of heat extracted from the hot reservoir is_________________?
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A. 667

B. 349

C. 651

D. 1000

35. Which of the following is Clausius-Clapeyron Equation for vaporisation of an ideal gas under the condition that the molar volume of liquid is negligible compared to that of the vapor ?
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A. d ln p/dt = RT2/Hvap

B. dp/dt = RT2/Hvap

C. d ln p/dt = Hvap/RT2

D. dp/dt = Hvap/RT2

36. A thermodynamic system is taken from state A to B along ACB and is brought back to A along BDA as shown below in the P-V diagram. The net work done during the complete cycle is given by the area covered by_________________?
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A. ADBB1A1A

B. P1ACBP2P1

C. ACBB1A1A

D. ACBDA
37. Requisites of a reversible process is that the ____________________?
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A. System and surroundings temperature be equal

B. Friction in the system should be absent

C. None of these

D. System and surroundings pressure be equal

38. Gibbs free energy (G) is represented by, G = H TS, whereas Helmholtz free energy, A. is given by, A = E TS. Which of the following is the Gibbs-Helmholtz equation ?
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A. [?(G/T)/?T] = (H/T2)

B. [?(A/T)/?T]V = E/T2

C. Both A. and B.

D. Neither A. nor B.

39. In a homogeneous solution, the fugacity of a component depends upon the __________________?
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A. Pressure

B. Composition

C. All (A), B. and (C)

D. Temperature

40. Chemical engineering thermodynamics is concerned with the ____________ in/of chemical processes?
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A. Calculation of rates

B. None of these

C. Energy transformation from one form to another

D. Reaction mechanism

41. Entropy change for an irreversible process taking system and surrounding together is___________________?
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A. 0

B. None of these

C. > 0

D. < 0

42. At constant temperature and pressure, for one mole of a pure substance, the ratio of the free energy to the chemical potential is____________________?
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A. Negative

B. Zero

C. Infinity

D. One
43. One mole of nitrogen at 8 bar and 600 K is contained in a piston-cylinder arrangement. It is brought to 1 bar isothermally against a resisting pressure of 1 bar. The work done (in Joules) by the gas is_________________?
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A. 4988.4

B. 30554

C. 4364.9

D. 10373
44. Joule-Thomson co-efficient is defined as__________________?
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A. ? = (?P/?T)H

B. ? = (?E/?T)H

C. ? = (?T/?P)H

D. ? = (?E/?P)H

45. Fugacity is most helpful in____________________?
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A. The study of chemical equilibria involving gases at atmospheric pressure

B. Representing actual behaviour of real gases

C. Representing actual behaviour of ideal gases

D. None of these

46. Claudes liquefaction process employs the cooling of gases by__________________?
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A. Expansion in an engine

B. None of these

C. Throttling

D. Following a constant pressure cycle

47. Which of the following is an undesirable characteristic of a refrigerant ?
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A. It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils

B. Its vapor pressure at the condenser temperature should be very high

C. None of these

D. It should be non-explosive

48. Which is an example of closed system ?
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A. Boiler

B. Air compressor

C. None of these

D. Liquid cooling system of an automobile
49. Gibbs free energy (F) is defined as__________________?
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A. F = E TS

B. F = H + TS

C. F = H TS

D. F = E + TS

50. The compressibility factor for an ideal gas is 1. Its value for any other real gas is_______________?
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A. 1

B. 1

C. Either B. or C, depends on the nature of the gas