4

# Gibbs free energy of a pure fluid approaches __________ as the pressure tends to zero at constant temperature.

Infinity

Minus infinity

Zero

None of these

B. Minus infinity

4

No

Any real

Only ideal

Both (B) and (C)

4

270

327

300

540

4

Volume

Temperature

Pressure

None of these

4

Isolated

Open

Insulated

Closed

4

Low T, low P

High T, high P

Low T, high P

High T, low P

4

# Gases are cooled in Joule-Thomson expansion, when it is __________ inversion temperature.

Below

At

Above

Either 'b' or 'c'

4

Superheated

Desuperheated

Non-condensable

None of these

4

Entropy

Temperature

Internal energy

Enthalpy

4

# Pick out the wrong statement.

The values of (∂P/∂V)T and (∂2P/∂V2)T are zero for a real gas at its critical point

Heat transferred is equal to the change in the enthalpy of the system, for a constant pressure, non-flow, mechanically reversible process

Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures

During a reversible adiabatic process, the entropy of a substance remains constant

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.

448

224

22.4

Data insufficient; can't be computed

4

# Standard temperature and pressure (S.T.P.) is

0°C and 750 mm Hg

15°C and 750 mm Hg

0°C and 1 kgf/cm2

15°C and 1 kgf/cm2

4

V1/V2

V2/V1

V1 - V2

V1.V2

4

Isothermal

Isobaric

Polytropic

4

# If two gases have same reduced temperature and reduced pressure, then they will have the same

Volume

Mass

Critical temperature

None of these

4

# High pressure steam is expanded adiabatically and reversibly through a well insulated turbine, which produces some shaft work. If the enthalpy change and entropy change across the turbine are represented by ΔH and ΔS respectively for this process:

Δ H = 0 and ΔS = 0

Δ H ≠ 0 and ΔS = 0

Δ H ≠ 0 and ΔS ≠ 0

Δ H = 0 and ΔS ≠ 0

4

Infinity

Unity

Constant

Negative

4

Zero

Positive

Negative

None of these

4

# Absolute zero temperature signifies the

Minimum temperature attainable

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

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

None of these

4

# Pick out the wrong statement:

The expansion of a gas in vacuum is an irreversible process

An isometric process is a constant pressure process

Entropy change for a reversible adiabatic process is zero

Free energy change for a spontaneous process is negative

4

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

Enhanced COP

Decreased COP

No change in the value of COP

Increased or decreased COP; depending upon the type of refrigerant

4

# Out of the following refrigeration cycles, which one has maximum COP?

Air cycle

Carnot cycle

Ordinary vapor compression cycle

Vapor compression with a reversible expansion engine

4

# Compressibility factor of a gas is

Not a function of its pressure

Not a function of its nature

Not a function of its temperature

Unity, if it follows PV = nRT

4

# Clausius-Clapeyron equation is applicable to __________ equilibrium processes.

Solid-vapor

Solid-liquid

Liquid-vapor

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

4

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

Reversible isothermal volume change

Heating of a substance

Cooling of a substance

Simultaneous heating and expansion of an ideal gas

4

# The standard Gibbs free energy change of a reaction depends on the equilibrium

Pressure

Temperature

Composition

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

4

Oxygen

Nitrogen

Air

Hydrogen

4

Specific volume

Work

Pressure

Temperature

4

# Reduced pressure of a gas is the ratio of its

Pressure to critical pressure

Critical pressure to pressure

Pressure to pseudocritical pressure

Pseudocritical pressure to pressure

4

# Fugacity and pressure are numerically not equal for the gases

At low temperature and high pressure

At standard state

Both (A) and (B)

In ideal state