Chemical Engineering Thermodynamics

51. Air-refrigeration cycle

1. Is the most efficient of all refrigeration cycles
2. Has very low efficiency
3. Requires relatively large quantities of air to achieve a significant amount of refrigeration
4. Both (B) and (C)

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52. All gases above its inversion temperature, in a throttling process will show

1. A heating effect
2. No change in temperature
3. A cooling effect
4. Either (A) or (C)

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53. All gases during throttling process at atmospheric temperature and pressure show a cooling effect except

1. CO₂
2. H₂
3. O₂
4. N₂

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54. All gases except _________ shows a cooling effect during throttling process at atmospheric temperature and pressure.

1. Oxygen
2. Nitrogen
3. Air
4. Hydrogen

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55. An ideal liquid refrigerant should

1. Not have a sub-atmospheric vapour pressure at the temperature in the refrigerator coils
2. Not have unduly high vapour pressure at the condenser temperature
3. Both (A) and (B)
4. Have low specific heat

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56. An irreversible process

1. Is the analog of linear frictionless motion in machines
2. Is an idealised visualisation of behaviour of a system
3. Yields the maximum amount of work
4. Yields an amount of work less than that of a reversible process

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57. An isentropic process is carried out at constant

1. Volume
2. Pressure
3. Temperature
4. All (A), (B) and (C)

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58. An isolated system can exchange _________ with its surroundings.

1. Matter
2. Energy
3. Neither matter nor energy
4. Both matter and energy

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59. Any substance above its critical temperature exists as

1. Saturated vapour
2. Solid
3. Gas
4. Liquid

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60. As pressure approaches zero, the ratio of fugacity to pressure (f/P) for a gas approaches

1. Zero
2. Unity
3. Infinity
4. An indeterminate value

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