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What is the correct answer?

4

It is desired to bring about a certain change in the state of a system by performing work on the system under adiabatic conditions.

A. The amount of work needed is path dependent

B. Work alone cannot bring out such a change of state

C. The amount of work needed is independent of path

D. More information is needed to conclude anything about the path dependence or otherwise of the work needed

Correct Answer :

A. The amount of work needed is path dependent


Related Questions

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4

In case of the decomposition of hydroiodic acid (2HI H2 + I2), addition of H2 (at equilibrium condition) will

A. Increase the partial pressure of I2

B. Decrease the partial pressure of HI

C. Diminish the degree of dissociation of HI

D. None of these

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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

Free energy change at equilibrium is

A. Zero

B. Positive

C. Negative

D. Indeterminate

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4

A system undergoes a change from a given initial state to a given final state either by an irreversible process or by a reversible process, then (where, Δ S1 and Δ SR are the entropy changes of the system for the irreversible and reversible processes respectively)

A. Δ S1 is always < Δ SR

B. Δ S1 is sometimes > Δ SR

C. Δ S1 is always > Δ SR

D. Δ S1 is always = Δ SR

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4

For an ideal gas, the enthalpy

A. Increases with rise in pressure

B. Decreases with rise in pressure

C. Is independent of pressure

D. Is a path function

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4

All gases except __________ shows a cooling effect during throttling process at atmospheric temperature and pressure.

A. Oxygen

B. Nitrogen

C. Air

D. Hydrogen

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4

When a gas is subjected to adiabatic expansion, it gets cooled due to

A. Decrease in velocity

B. Decrease in temperature

C. Decrease in kinetic energy

D. Energy spent in doing work

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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

All gases above its inversion temperature, in a throttling process will show

A. A heating effect

B. No change in temperature

C. A cooling effect

D. Either (A) or (C)

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4

Pick out the correct equation relating 'F' and 'A'.

A. F = A + PV

B. F = E + A

C. F = A - TS

D. F = A + TS

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4

A refrigerator may be termed as a

A. Heat pump

B. Heat engine

C. Carnot engine

D. None of these

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4

As the temperature is lowered towards the absolute zero, the value of ∂(ΔF)/∂T, then approaches

A. Unity

B. Zero

C. That of the heat of reaction

D. Infinity

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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

__________ 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

In Joule-Thomson porous plug experiment, the

A. Enthalpy does not remain constant

B. Entire apparatus is exposed to surroundings

C. Temperature remains constant

D. None of these

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4

During a reversible isothermal expansion of an ideal gas, the entropy change is

A. +ve

B. 0

C. -ve

D.

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4

Gibbs free energy (G) is represented by, G = H - TS, whereas Helmholtz free energy, (A) is given by, A = E - TS. Which of the following is the Gibbs-Helmholtz equation?

A. [∂(G/T)/∂T] = - (H/T2)

B. [∂(A/T)/∂T]V = - E/T2

C. Both (A) and (B)

D. Neither (A) nor (B)

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4

The adiabatic throttling process of a perfect gas is one of constant enthalpy

A. In which there is a temperature drop

B. Which is exemplified by a non-steady flow expansion

C. Which can be performed in a pipe with a constriction

D. In which there is an increase in temperature

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4

Work done may be calculated by the expression ∫ p dA for __________ processes.

A. Non-flow reversible

B. Adiabatic

C. Both (A) and (B)

D. Neither (A) nor (B)

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4

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

A. Increased COP

B. Same COP

C. Decreased COP

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

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4

Internal energy change of a system over one complete cycle in a cyclic process is

A. Zero

B. +ve

C. -ve

D. Dependent on the path

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4

For a constant pressure reversible process, the enthalpy change (ΔH) of the system is

A. Cv.dT

B. Cp.dT

C. ∫ Cp.dT

D. ∫ Cv.dT

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4

Pick out the wrong statement.

A. A refrigeration cycle violates the second law of thermodynamics

B. Refrigeration cycle is normally represented by a temperature vs. entropy plot

C. In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases

D. One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW

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4

As the time is passing, entropy of the universe

A. Is increasing

B. Is decreasing

C. Remain constant

D. Data insufficient, can't be predicted

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4

The four properties of a system viz. P, V, T, S are related by __________ equation.

A. Gibbs-Duhem

B. Gibbs-Helmholtz

C. Maxwell's

D. None of these

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4

Which of the following behaves most closely like an ideal gas?

A. He

B. N2

C. O2

D. H2

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4

For an ideal liquid solution, which of the following is unity?

A. Activity

B. Fugacity

C. Activity co-efficient

D. Fugacity co-efficient

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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

Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the

A. Low pressure and high temperature

B. Low pressure and low temperature

C. High pressure and low temperature

D. High pressure and high temperature

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4

Refrigerants commonly used for domestic refrigerators are

A. Ethyl chloride or methyl chloride

B. Freon-12

C. Propane

D. NH3 or CO2