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Free energy

A. Decreases in all spontaneous (or irreversible) processes

B. Change during a spontaneous process has a negative value

C. Remains unchanged in reversible processes carried at constant temperature and pressure

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

Correct Answer :

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


Related Questions

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Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ____with the increase of reduced temperature.

A. Decreases

B. Increases

C. Remains constant

D. Decreases logarithmically

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4

The work done in isothermal compression compared to that in adiabatic compression will be

A. Less

B. More

C. Same

D. More or less depending upon the extent of work done

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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

If two pure liquid constituents are mixed in any proportion to give an ideal solution, there is no change in

A. Volume

B. Enthalpy

C. Both (A) & (B)

D. Neither (A) nor (B)

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4

A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system

A. its internal energy (U) decreases and its entropy (S) increases

B. U and S both decreases

C. U decreases but S is constant

D. U is constant but S decreases

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4

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

A. 349

B. 651

C. 667

D. 1000

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4

__________ functions are exemplified by heat and work.

A. Path

B. Point

C. State

D. None of these

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4

Specific volume of an ideal gas is

A. Equal to its density

B. The reciprocal of its density

C. Proportional to pressure

D. None of these

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4

The temperature at which both liquid and gas phases are identical, is called the __________ point.

A. Critical

B. Triple

C. Freezing

D. Boiling

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4

Degree of freedom of the system ice-watervapour will be

A. 0

B. 1

C. 2

D. 3

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4

In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in

A. Enhanced COP

B. Decreased COP

C. No change in the value of COP

D. Increased or decreased COP; depending upon the type of refrigerant

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4

The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition.

A. Internal energy

B. Enthalpy

C. Gibbs free energy

D. Helmholtz free energy

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4

Air enters an adiabatic compressor at 300K. The exit temperature for a compression ratio of 3, assuming air to be an ideal gas (Y = Cp/Cv = 7/5) and the process to be reversible, is

A. 300 × (32/7)

B. 300 × (33/5)

C. 300 × (333/7)

D. 300 × (35/7)

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4

Van Laar equation deals with the activity coefficients in

A. Binary solutions

B. Ternary solutions

C. Azeotropic mixture only

D. None of these

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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

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

Filling of gas from a high pressure cylinder into small bottles is an example of a/an __________ process.

A. Equilibrium

B. Adiabatic

C. Steady

D. Unsteady

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4

The equation relating E, P, V and T which is true for all substances under all conditions is given by (∂E/∂V)T = T(∂P/∂T)H - P. This equation is called the

A. Maxwell's equation

B. Thermodynamic equation of state

C. Equation of state

D. Redlich-Kwong equation of state

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4

A Carnot cycle consists of the following steps:

A. Two isothermal and two isentropic

B. Two isobaric and two isothermal

C. Two isochoric and two isobaric

D. Two isothermals and two isochoric

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4

At equilibrium condition, the chemical potential of a material in different phases in contact with each other is equal. The chemical potential for a real gas (μ) is given by (where, μ = standard chemical potential at unit fugacity (f° = 1 atm.) and the gas behaves ideally.)

A. μ° + RT ln f

B. μ°+ R ln f

C. μ° + T ln f

D. μ° + R/T ln f

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4

First law of thermodynamics deals with the

A. Direction of energy transfer

B. Reversible processes only

C. Irreversible processes only

D. None of these

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4

Cp - Cv = R is valid for __________ gases.

A. Ideal

B. Very high pressure

C. Very low temperature

D. All of the above

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4

Which law of the thermodynamics provides basis for measuring the thermodynamic property?

A. First law

B. Zeroth law

C. Third law

D. Second law

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4

Ideal gas law is applicable at

A. Low T, low P

B. High T, high P

C. Low T, high P

D. High T, low P

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4

__________ calorimeter is normally used for measuring the dryness fraction of steam, when it is very low.

A. Bucket

B. Throttling

C. Separating

D. A combination of separating & throttling

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4

The principle applied in liquefaction of gases is

A. Adiabatic expansion

B. Joule-Thomson effect

C. Both (A) and (B)

D. Neither (A) nor (B)

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4

Cv for an ideal gas

A. Does not depend upon temperature

B. Is independent of pressure only

C. Is independent of volume only

D. Is independent of both pressure and volume

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4

Which of the following is not correct for a reversible adiabatic process?

A. TVγ-1 = constant

B. p1-γ.TY = constant

C. PVγ = constant

D. None of these

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4

Which one is true for a throttling process?

A. A gas may have more than one inversion temperatures

B. The inversion temperature is different for different gases

C. The inversion temperature is same for all gases

D. The inversion temperature is the temperature at which Joule-Thomson co-efficient is infinity

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4

A cylinder contains 640 gm of liquid oxygen. The volume occupied (in litres) by the oxygen, when it is released and brought to standard conditions (0°C, 760 mm Hg) will be __________ litres.

A. 448

B. 224

C. 22.4

D. Data insufficient; can't be computed