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4

Number of components (C), phase (P) and degrees of freedom (F) are related by Gibbs phase rule as

A. P + F - C = 2

B. C = P - F + 2

C. F = C - P - 2

D. P = F - C - 2

Correct Answer :

A. P + F - C = 2


Related Questions

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4

A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect?

A. Vapor compression cycle using expansion valve

B. Air refrigeration cycle

C. Vapor compression cycle using expansion engine

D. Carnot refrigeration cycle

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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

At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero. This follows from the

A. Third law of thermodynamics

B. Second law of thermodynamics

C. Nernst heat theorem

D. Maxwell's relations

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4

The internal energy of an incompressible fluid depends upon its

A. Pressure

B. Temperature

C. Both (A) & (B)

D. Neither (A) nor (B)

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4

Melting of ice is an example of an __________ process.

A. Adiabatic

B. Isothermal

C. Isometric

D. None of these

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4

Enthalpy changes over a constant pressure path are always zero for __________ gas.

A. Any

B. A perfect

C. An easily liquefiable

D. A real

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4

The value of Cp & Cv respectively for monatomic gases in Kcal/kg Mole.°K are

A. 5 & 3

B. 3.987 & 1.987

C. 1.987 & 0.66

D. 0.66 & 1.987

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4

Charles' law for gases states that

A. V/T = Constant

B. V ∝ 1/T

C. V ∝ 1/P

D. PV/T = Constant

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4

For a spontaneous process, free energy

A. Is zero

B. Increases

C. Decreases whereas the entropy increases

D. And entropy both decrease

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4

When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is

A. More in vapour phase

B. More in liquid phase

C. Same in both the phases

D. Replaced by chemical potential which is more in vapour phase

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4

PVy = constant, holds good for an isentropic process, which is

A. Reversible and isothermal

B. Isothermal and irreversible

C. Reversible and adiabatic

D. Adiabatic and irreversible

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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

Cp of a gas at its critical temperature and pressure

A. Becomes zero

B. Becomes infinity

C. Equals 1 kcal/kmol °K

D. Equals 0.24 kcal/kmol °K

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4

One ton of refrigeration is defined as the heat rate corresponding to melting of one ton of ice in one

A. Hour

B. Day

C. Minute

D. Second

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4

The partial pressure of each constituent present in an alloy is __________ the total vapor pressure exerted by the alloy.

A. Less than

B. Equal to

C. More than

D. Either (B) or (C); depends on the type of alloy

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4

Absolute zero temperature signifies the

A. Minimum temperature attainable

B. Temperature of the heat reservoir to which a Carnot engine rejects all the heat that is taken in

C. Temperature of the heat reservoir to which a Carnot engine rejects no heat

D. None of these

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4

Pick out the wrong statement.

A. Activity co-efficient is dimensionless.

B. In case of an ideal gas, the fugacity is equal to its pressure.

C. In a mixture of ideal gases, the fugacity of a component is equal to the partial pressure of the component.

D. The fugacity co-efficient is zero for an ideal gas

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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

In reactions involving solids and liquids (where change in volume is negligible), the heat of reaction at constant pressure as compared to that at constant volume is

A. More

B. Less

C. Same

D. Unpredictable; depends on the particular reaction

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4

In an ideal gas mixture, fugacity of a species is equal to its

A. Vapor pressure

B. Partial pressure

C. Chemical potential

D. None of these

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4

Efficiency of a heat engine working on Carnot cycle between two temperature levels depends upon the

A. Two temperatures only

B. Pressure of working fluid

C. Mass of the working fluid

D. Mass and pressure both of the working fluid

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4

The number of degrees of freedom for an azeotropic mixture in a two component vapour-liquid equilibria is/are

A. Zero

B. One

C. Two

D. Three

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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

Internal energy of an ideal gas

A. Increases with increase in pressure

B. Decreases with increase in temperature

C. Is independent of temperature

D. None of these

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4

Entropy change for an irreversible process taking system and surrounding together is

A. 0

B. > 0

C. < 0

D. None of these

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4

Third law of thermodynamics is concerned with the

A. Value of absolute entropy

B. Energy transfer

C. Direction of energy transfer

D. None of these

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4

Which of the following is Virial equation of state?

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

B. PV = nRT

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

D. None of these

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4

Pick out the wrong statement

A. Phase rule variables are intensive properties

B. Heat and work are both state function

C. The work done by expansion of a gas in vacuum is zero

D. CP and CV are state function

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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

Pick out the correct statement.

A. Like internal energy and enthalpy, the absolute value of standard entropy for elementary substances is zero

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

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

D. Maximum work is done under reversible conditions