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4

During Joule-Thomson expansion of gases

A. Enthalpy remains constant

B. Entropy remains constant

C. Temperature remains constant

D. None of these

Correct Answer :

A. Enthalpy remains constant


Related Questions

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4

Free energy changes for two reaction mechanism 'X' and 'Y are respectively - 15 and - 5 units. It implies that X is

A. Slower than Y

B. Faster than Y

C. Three times slower than Y

D. Three times faster than Y

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4

While dissolving a gas into a liquid at a constant temperature, the ratio of the concentration of the gas in the solution phase and in the gaseous phase is

A. Infinity

B. Unity

C. Constant

D. Negative

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4

In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respectively, the Carnot COP will be

A. 5.2

B. 6.2

C. 0.168

D. Data insufficient, can't be found out

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4

In the equation, PVn = constant, if the value of n is in between 1 and y (i.e. Cp/Cv), then it represents a reversible __________ process.

A. Isometric

B. Polytropic

C. Isentropic

D. Isobaric

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4

__________ decreases during adiabatic throttling of a perfect gas.

A. Entropy

B. Temperature

C. Enthalpy

D. Pressure

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4

The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is

A. Less

B. More

C. Same

D. Dependent on climatic conditions

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4

A gas can be liquefied by pressure alone only, when its temperature is __________ its critical temperature.

A. Less than

B. More than

C. Equal to or higher than

D. Less than or equal to

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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

A refrigeration cycle is the same as a __________ cycle,

A. Turbine

B. Heat engine

C. Reversed heat engine

D. None of these

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4

The third law of thermodynamics states that the

A. Heat capacity of a crystalline solid is zero at absolute zero temperature

B. Heat transfer from low temperature to high temperature source is not possible without external work

C. Gases having same reduced properties behaves similarly

D. None of these

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4

The rate at which a substance reacts is proportional to its active mass and the rate of a chemical reaction is proportional to the product of active masses of the reacting substances. This is the

A. Lewis-Randall rule

B. Statement of Van't Hoff Equation

C. Le-Chatelier's principle

D. None of these

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4

With increase in compression ratio, the efficiency of the otto engine

A. Increases

B. Decreases

C. Remain constant

D. Increases linearly

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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

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

In the decomposition of PCl5 represented by, PCl5 PCl3 + Cl2, decrease in the pressure of the system will __________ the degree of dissociation of PCl5.

A. Increase

B. Decrease

C. Not alter

D. None of these

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4

The number of degrees of freedom for a mixture of ice and water (liquid) are

A. 3

B. 2

C. 1

D. 0

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4

Solid and liquid phases of a substance are in equilibrium at the

A. Critical temperature

B. Melting point

C. Freezing point

D. Both (B) and (C)

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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

At __________ point, all the three phases (i.e. solid, liquid and gas) co-exist.

A. Eutectic

B. Triple

C. Plait

D. Critical

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4

A thermodynamic system is taken from state A to B along ACB and is brought back to A along BDA as shown below in the P-V diagram. The net work done during the complete cycle is given by the area covered by

A. P1ACBP2P1

B. ACBB1A1A

C. ACBDA

D. ADBB1A1A

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4

In an isothermal process on an ideal gas, the pressure increases by 0.5 percent. The volume decreases by about __________ percent.

A. 0.25

B. 0.5

C. 0.75

D. 1

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4

In a working refrigerator, the value of COP is always

A. 0

B. < 0

C. < 1

D. > 1

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4

Those solutions in which there is no volume change upon mixing the components in the liquid state and which, when diluted do not undergo any heat change (i.e. heat of dilution is zero), are called __________ solutions.

A. Ideal

B. Real

C. Isotonic

D. None of these

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4

The thermodynamic law, PVy = constant, is not applicable in case of

A. Ideal compression of air

B. Free expansion of an ideal gas

C. Adiabatic expansion of steam in a turbine

D. Adiabatic compression of a perfect gas

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4

Which of the following is not a unit of the equilibrium constant Kp? (where, Δx = number of moles of products number of moles of reactants)

A. (atm)Δx, when Δx is negative

B. (atm)Δx, when Δx is positive

C. Dimensionless, when Δx = 0

D. (atm)Δx2, when Δx > 0

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4

Maximum work that could be secured by expanding the gas over a given pressure range is the __________ work.

A. Isothermal

B. Adiabatic

C. Isentropic

D. None of these

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4

Any substance above its critical temperature exists as

A. Saturated vapour

B. Solid

C. Gas

D. Liquid

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4

The expression, nRT ln(P1/P2), is for the __________of an ideal gas.

A. Compressibility

B. Work done under adiabatic condition

C. Work done under isothermal condition

D. Co-efficient of thermal expansion

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4

Chemical potential is a/an

A. Extensive property

B. Intensive property

C. Force which drives the chemical system to equilibrium

D. Both (B) and (C)

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4

The unit of fugacity is the same as that of the

A. Pressure

B. Temperature

C. Volume

D. Molar concentration