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What is the correct answer?

4

The expression for entropy change given by, ΔS = nR ln (V2/V1) + nCv ln (T2/T1) is valid for

A. Reversible isothermal volume change

B. Heating of a substance

C. Cooling of a substance

D. Simultaneous heating and expansion of an ideal gas

Correct Answer :

D. Simultaneous heating and expansion of an ideal gas


Related Questions

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4

Ideal refrigeration cycle is

A. Same as Carnot cycle

B. Same as reverse Carnot cycle

C. Dependent on the refrigerant's properties

D. The least efficient of all refrigeration processes

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4

What is the number of degree of freedom for a system of two miscible non-reacting species in vapor-liquid equilibrium forming an azeotrope?

A. 0

B. 2

C. 1

D. 3

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4

The enthalpy change when ammonia gas is dissolved in water is called the heat of

A. Solution

B. Formation

C. Dilution

D. Combustion

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4

In the ammonia synthesis reaction, N2 + 3H2 2NH3 + 22.4 kcal, the formation of NH3 will be favoured by

A. High temperature

B. Low pressure

C. Low temperature only

D. Both low temperature and high pressure

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4

The extensive properties are

A. Volume, mass and number of moles

B. Free energy, entropy and enthalpy

C. Both (A) and (B)

D. None of these

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4

Melting of ice exemplifies a/an

A. Adiabatic process

B. Endothermic reaction

C. Exothermic reaction

D. Process involving a chemical reaction

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4

Which of the following is true for Virial equation of state?

A. Virial co-efficients are universal constants

B. Virial co-efficients 'B' represents three body interactions

C. Virial co-efficients are function of temperature only

D. For some gases, Virial equations and ideal gas equations are the same

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4

Pick out the wrong statement.

A. The conversion for a gas phase reaction increases with decrease in pressure, if there is an increase in volume accompanying the reaction

B. With increase in temperature, the equilibrium constant increases for an exothermic reaction

C. The equilibrium constant of a reaction depends upon temperature only

D. The conversion for a gas phase reaction increases with increase in pressure, if there is a decrease in volume accompanying the reaction

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4

Air-refrigeration cycle

A. Is the most efficient of all refrigeration cycles

B. Has very low efficiency

C. Requires relatively large quantities of air to achieve a significant amount of refrigeration

D. Both (B) and (C)

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4

Internal energy is equal to the heat absorbed in case of a/an __________ process.

A. Constant volume

B. Polytropic

C. Adiabatic

D. Constant pressure

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4

Out of the following refrigeration cycles, which one has the minimum COP (Co-efficient of performance)?

A. Air cycle

B. Carnot cycle

C. Ordinary vapour compression cycle

D. Vapour compression with a reversible expansion engine

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4

Gibbs-Helmholtz equation is

A. ΔF = ΔH + T [∂(ΔF)/∂T]P

B. ΔF = ΔH - TΔT

C. d(E - TS) T, V < 0

D. dP/dT = ΔHvap/T.ΔVvap

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4

Which is not constant for an ideal gas?

A. (∂P/∂V)T

B. (∂V/∂T)P

C. (∂P/∂V)V

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

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4

What is the value of maximum COP in case of absorption refrigeration, if refrigeration provided is at temperature, TR (where, T1 and T2 are source & surrounding temperatures respectively.)?

A. TR/(T2 - TR) × (T1 - T2)/T1

B. TR/(T2 - TR) × T1/(T1 - T2)

C. TR/(T1 - TR) × (T1 - T2)/T1

D. None of these

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4

(∂E/∂T)V is the mathematical expression for

A. CV

B. Enthalpy change

C. Free energy change

D. None of these

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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

Cv is given by

A. (∂E/∂T)V

B. (∂E/∂V)T

C. (∂E/∂P)V

D. (∂V/∂T)P

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4

Isotherm on an enthalpy-concentration diagram, for an ideal solution will be a

A. Straight line

B. Sine curve

C. Parabola

D. Hyperbola

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4

1st law of thermodynamics is nothing but the law of conservation of

A. Momentum

B. Mass

C. Energy

D. None of these

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4

Extensive properties of a thermodynamic system depend upon the __________ of the system.

A. Specific volume

B. Temperature

C. Mass

D. Pressure

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4

The relation connecting the fugacities of various components in a solution with one another and to composition at constant temperature and pressure is called the __________ equation.

A. Gibbs-Duhem

B. Van Laar

C. Gibbs-Helmholtz

D. Margules

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4

A chemical reaction will occur spontaneously at constant pressure and temperature, if the free energy is

A. Zero

B. Positive

C. Negative

D. None of these

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4

Critical solution temperature (or the consolute temperature) for partially miscible liquids (e.g., phenol-water) is the minimum temperature at which

A. A homogeneous solution (say of phenol water) is formed

B. Mutual solubility of the two liquids shows a decreasing trend

C. Two liquids are completely separated into two layers

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

The expression for entropy change given by, ΔS = - nR ln (P2/P1), holds good for

A. Expansion of a real gas

B. Reversible isothermal volume change

C. Heating of an ideal gas

D. Cooling of a real gas

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4

Pick out the wrong statement:

A. The expansion of a gas in vacuum is an irreversible process

B. An isometric process is a constant pressure process

C. Entropy change for a reversible adiabatic process is zero

D. Free energy change for a spontaneous process is negative

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4

Which of the following equations is obtained on combining 1st and 2nd law of thermodynamics, for a system of constant mass?

A. dE = Tds - PdV

B. dQ = CvdT + PdV

C. dQ = CpdT + Vdp

D. Tds = dE - PdV

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4

Which of the following diagrams does not represent an Otto cycle?

A.

B.

C.

D. None of these

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4

Entropy of a substance remains constant during a/an __________ change.

A. Reversible isothermal

B. Irreversible isothermal

C. Reversible adiabatic

D. None of these

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4

The expression for entropy change, ΔS = n Cp . ln (T2/T1), is valid for the __________ of a substance.

A. Simultaneous pressure & temperature change

B. Heating

C. Cooling

D. Both (B) and (C)