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4

Isentropic process means a constant __________ process.

A. Enthalpy

B. Pressure

C. Entropy

D. None of these

Correct Answer :

C. Entropy


Related Questions

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4

Which of the following is not a reversible process?

A. Expansion of an ideal gas against constant pressure

B. Atmospheric pressure vaporisation of water at 100°C

C. Solution of NaCl in water at 50°C

D. None of these

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4

A system is said to be at equilibrium, if the entropy of the system has reached __________ value.

A. Minimum

B. Zero

C. Maximum

D. None of these

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4

When a gas is expanded from high pressure region to low pressure region; temperature change occurs. This phenomenon is related to the

A. Gibbs-Duhem equation

B. Gibbs-Helmholtz equation

C. Third law of thermodynamics

D. Joule-Thomson effect

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4

If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the

A. Maxwell's equation

B. Clausius-Clapeyron Equation

C. Van Laar equation

D. Nernst Heat Theorem

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4

Specific/molar Gibbs free energy for a pure substance does not change during

A. Sublimation

B. Vaporisation

C. Melting

D. Either (A), (B) or (C)

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4

Pick out the wrong statement.

A. Enthalpies of all elements in their standard states are assumed to be zero

B. Combustion reactions are never endothermic in nature

C. Heat of reaction at constant volume is equal to the change in internal energy

D. Clausius-Clapeyron equation is not applicable to melting process

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4

When pressure is applied on the system, ice ↔ water, then

A. Equilibrium cannot be established

B. More ice will be formed

C. More water will be formed

D. Evaporation of water will take place

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4

The kinetic energy of gas molecule is zero at

A. 0°C

B. 273°C

C. 100°C

D. -273°C

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4

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

A. 30554

B. 10373

C. 4988.4

D. 4364.9

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4

In case of a close thermodynamic system, there is __________ across the boundaries.

A. No heat and mass transfer

B. No mass transfer but heat transfer

C. Mass and energy transfer

D. None of these

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4

If heat contents of CH4, C2H4 and C3H8 are -17.9, 12.5 and -24.8 kcal/mole respectively, than ΔH for the reaction CH4(g) + C2H4(g) C3H8(g) will be __________ Kcal.

A. -19.4

B. -30.2

C. 55.2

D. -55.2

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4

Enthalpy 'H' is defined as

A. H = E - PV

B. H = F - TS

C. H - E = PV

D. None of these

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4

For a given substance at a specified temperature, activity is __________ to fugacity.

A. Directly proportional

B. Inversely proportional

C. Equal

D. None of these

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4

__________ does not change during phase transformation processes like sublimation, melting & vaporisation.

A. Entropy

B. Gibbs free energy

C. Internal energy

D. All (A), (B) & (C)

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4

Degree of freedom of a system consisting of a gaseous mixture of H2 and NH3 will be

A. 0

B. 1

C. 2

D. 3

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4

Pick out the correct statement.

A. The available energy in an isolated system for all irreversible (real) processes decreases

B. The efficiency of a Carnot engine increases, if the sink temperature is decreased

C. The reversible work for compression in non-flow process under isothermal condition is the change in Helmholtz free energy

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

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4

Heat evolved/absorbed during conversion of a substance from one allotropic form to another is termed as the heat of

A. Fusion

B. Vaporisation

C. Transition

D. None of these

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4

The main feature of Carnot refrigeration cycle is that, it

A. Does not need the addition of external work for its functioning

B. Transfers heat from high temperature to low temperature

C. Accomplishes the reverse effect of the heat engine

D. None of these

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4

Compressibility factor-reduced pressure plot on reduced co-ordinates facilitates

A. Use of only one graph for all gases

B. Covering of wide range

C. Easier plotting

D. More accurate plotting

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4

A refrigerator may be termed as a

A. Heat pump

B. Heat engine

C. Carnot engine

D. None of these

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4

Pick out the undesirable property for a good refrigerant.

A. High thermal conductivity

B. Low freezing point

C. Large latent heat of vaporisation

D. High viscosity

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4

A large iceberg melts at the base, but not at the top, because of the reason that

A. Ice at the base contains impurities which lowers its melting point

B. Due to the high pressure at the base, its melting point reduces

C. The iceberg remains in a warmer condition at the base

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

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4

Sound waves propagation in air exemplifies an __________ process.

A. Adiabatic

B. Isothermal

C. Isometric

D. None of these

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4

A solid is transformed into vapour without going to the liquid phase at

A. Triple point

B. Boiling point

C. Below triple point

D. Always

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4

Joule-Thomson Co-efficient at any point on the inversion curve is

A.

B. +ve

C. 0

D. -ve

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4

Which of the following is not a common refrigerant?

A. Freon-12

B. Ethylene

C. Ammonia

D. Carbon dioxide

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4

Which of the following is an extensive property of a system?

A. Heat capacity

B. Molal heat capacity

C. Pressure

D. Concentration

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4

At a given temperature, the volume of a gas dissolved in a solvent __________ with increase in pressure.

A. Increases

B. Decreases

C. Remains unchanged

D. May increase or decrease; depends on the gas

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4

One ton of refrigeration capacity is equivalent to the heat removal rate of

A. 50 kcal/hr

B. 200 BTU/hr

C. 200 BTU/minute

D. 200 BTU/day

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4

Internal energy of an element at 1 atm and 25° C is __________ kcal/kg.mole.

A. 0

B. 273

C. 25

D. None of these