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Chemical Engineering Thermodynamics MCQ Questions & Answers

Chemical Engineering Thermodynamics MCQs : This section focuses on the "Chemical Engineering Thermodynamics". These Multiple Choice Questions (MCQs) should be practiced to improve the Chemical Engineering Thermodynamics skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.




Question 1

"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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Question 2

In jet refrigerators, the refrigerating fluid is practically always

A. water
B. ammonia
C. freon
D. brine

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Question 3

Boyle's law for gases states that

A. , when temperature is constant.
B. , when temperature & mass of the gas remain constant.
C. P ∝ V, at constant temperature & mass of the gas.
D. Err:509

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Question 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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Question 5

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

A. Air cycle
B. Carnot cycle
C. Ordinary vapor compression cycle
D. Vapor compression with a reversible expansion engine

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Question 6

The accentric factor of a materical, 'ω', is defined as ω = -log10(Prsat)Tr-1 = 0.7, where, Prsat = reduced vapor pressure, Tr = reduced temperature. The value of accentric factor is always

A. > 2
B. < 1
C. > 1
D. < 3

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Question 7

Equilibrium constant decreases as the temperature

A. increases, for an exothermic reaction.
B. decreases, for an exothermic reaction.
C. increases, for an endothermic reaction.
D. none of these.

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Question 8

Entropy is a measure of the __________ of a system.

A. disorder
B. orderly behaviour
C. temperature changes only
D. none of these

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Question 9

Compressibility factor for almost all the gases are approximately same at the same

A. pressure and temperature.
B. reduced pressure and reduced temperature.
C. critical pressure and critical temperature.
D. none of these.

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Question 10

In a working refrigerator, the value of COP is always

A. 0
B. < 0
C. < 1
D. > 1

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Question 11

In a reversible chemical reaction (where, Δx = number of moles of products-number of moles of reactants )

A. addition of inert gas favours the forward reaction, when Δx is positive.
B. pressure has no effect on equilibrium, when Δn = 0.
C. addition of inert gas has no effect on the equilibrium constant at constant volume for any value of Δx (+ ve, - ve) or zero).
D. all 'a', 'b' & 'c'.

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Question 12

Out of the following refrigration 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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Question 13

High __________ is an undesirable property for a good refrigerant.

A. specific heat
B. latent heat of vaporisation
C. viscosity
D. specific vapor volume

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Question 14

For a stable phase at constant pressure and temperature, the fugacity of each component in a binary system __________ as its mole fraction increases.

A. decreases
B. increases
C. remains same
D. decreases linearly

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Question 15

Which of the following is not an intensive property ?

A. Chemical potential
B. Surface tension
C. Heat capacity
D. None of these

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Question 16

The freezing point of a liquid decreases when the pressure is increased, if the liquid __________ while freezing.

A. contracts
B. expands
C. does not change in volume
D. either (a), (b) or (c)

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Question 17

In any spontaneous process,

A. only F decreases
B. only A decreases
C. both F and A decreases
D. both F and A increase

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Question 18

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

A. zero
B. #NAME?
C. #NAME?
D. dependent on the path

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Question 19

The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.

A. kinematic viscosity
B. work
C. temperature
D. none of these

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Question 20

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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Question 21

__________ increases with increase in pressure.

A. The melting point of wax
B. The boiling point of a liquid
C. both (a) and (b)
D. neither (a) nor (b)

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Question 22

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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Question 23

No work is done by the system, when a reaction occurs at constant

A. volume
B. temperature
C. pressure
D. none of these

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Question 24

Fundamental principle of refrigeration is based on the __________ law of thermodynamics.

A. zeroth
B. first
C. second
D. third

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Question 25

Joule-Thomson experiment is

A. isobaric
B. adiabatic
C. isenthalpic
D. both(b) & (c)

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Question 26

Water on heating from 1 to 4°C

A. contracts
B. expands
C. has same volume
D. may contract or expand

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Question 27

Isobaric process means a constant process.

A. temperature
B. pressure
C. volume
D. entropy

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Question 28

Heating of water under atmospheric pressure is an __________ process.

A. isochoric
B. isobaric
C. adiabatic
D. isothermal

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Question 29

The theoretical minimum work required to separate one mole of a liquid mixture at 1 atm, containing 50 mole % each of n- heptane and n- octane into pure compounds each at 1 atm is

A. -2 RT ln 0.5
B. -RT ln 0.5
C. 0.5 RT
D. 2 RT

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Question 30

If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the

A. Maxwell's equation
B. Clayperon-Claussius equation
C. Van Laar equation
D. Nernst Heat Theorem

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Question 31

During Joule-Thomson expansion of gases

A. enthalpy remains constant.
B. entropy remains constant.
C. temperature remains constant.
D. none of these.

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Question 32

Degress of freedom at triple point will be

A. 0
B. 1
C. 2
D. 3

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Question 33

Pick out the wrong statement.

A. Activity co-efficient is dimensionless.
B. In case of an ideal gas, the fagacity 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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Question 34

"Law of corresponding states" says that

A. , two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same.
B. the surface of separation (i. e. the meniscus) between liquid and vapour phase disappears at the critical temperature.
C. no gas can be liquified above the critical temperature, howsoever high the pressure may be.
D. the molar heat of energy of gas at constant volume should be nearly constant (about 3 calories).

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Question 35

Measurement of thermodynamic property of temperature is facilitated by __________ law of thermodynamics.

A. 1st
B. zeroth
C. 3rd
D. none of these

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Question 36

All gases during throttling process at atmospheric temperature and pressure show a cooling effect except

A. CO2
B. H2
C. O2
D. N2

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Question 37

Pick out the correct statement.

A. Compression ratio of an Otto engine is comparatively higher than a diesel engine.
B. Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio.
C. Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat.
D. Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work.

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Question 38

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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Question 39

A refrigerator may be termed as a

A. heat pump
B. heat engine
C. Carnot engine
D. none of these

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Question 40

Van Laar equation deals with the activity co-efficients in

A. binary solutions
B. ternary solutions
C. azeotropic mixture only
D. none of these

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Question 41

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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Question 42

Keeping the pressure constant, to double the volume of a given mass of an ideal gas at 27°C, the temperature should be raised to __________ °C.

A. 270
B. 327
C. 300
D. 540

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Question 43

Entropy of an ideal gas depends upon its

A. pressure
B. temperature
C. both (a) & (b)
D. neither (a) nor (b)

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Question 44

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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Question 45

Which of the following is a thermodynamic property of a system ?

A. Concentration
B. Mass
C. Temperature
D. Entropy

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Question 46

Pick out the correct statement:

A. In an isothermal system, irreversible work is more than reversible work.
B. Under reversible conditions, the adiabatic work is less than isothermal work.
C. Heat, work, enthalpy and entropy are all 'state functions'.
D. Matter and energy can not be exchanged with the surroundings in a closed system.

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Question 47

Linde gas liquefaction process employs cooling

A. by throttling
B. by expansion in an engine
C. at constant pressure
D. none of these

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