Process and Solution Thermodynamics (Archived) Flashcards by Patrick G.

Sublimation temperature of dry ice (solid CO2) is
___°C.

-78

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The equation relating E, P, V, and T which is true for all substances under all conditions is given by (𝜕E/𝜕V)T = T(𝜕P/𝜕T)H - P. This equation is called the ____.
a. Maxwell Equation
b. Thermodynamic Equation of State
c. Equation of State
d. Redlich-Kwong Equation of State

Thermodynamic Equation of State

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Henry’s law is closely obeyed by a gas, when its ____ is extremely high.
a. Pressure
b. Solubility
c. Temperature
d. None of these

d. None of these

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If an ideal solution is formed by mixing two pure liquids in any proportion, then the ____ of mixing is zero.
a. Enthalpy
b. Volume
c. Both A and B
d. Neither A nor B

Both A and B

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The ammonia synthesis reaction represented by N2 + 3 H2 ↔ 2 NH3; ∆H = −22.4 kcal is
a. Endothermic
b. Exothermic
c. Isothermal
d. Adiabatic

Exothermic

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

Faster than Y

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Which of the following has the minimum value of COP for a given refrigeration effect?
a. Reverse Carnot Cycle
b. Ordinary Vapour-Compression Cycle
c. Vapor-compression process with a reversible
expansion engine
d. Air refrigeration cycle

Air refrigeration cycle

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No work is done by the system, when a reaction occurs at constant
a. Volume
b. Temperature
c. Pressure
d. None of these

Volume

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In the reaction, H2 + I2 ↔ 2HI, addition of an inert gas will

Not affect the equilibrium conditions

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The work done in isothermal compression compared to that in adiabatic compression will be

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What happens in a reversible adiabatic expansion process?

Cooling takes place

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Which of the following is affected by the temperature?
a. Fugacity
b. Activity coefficient
c. Free energy
d. All of the above

All of the above

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Which is an example of closed system?
a. Air compressor
b. Liquid cooling system of an automobile
c. Boiler
d. None of these

Liquid cooling system of an automobile

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Entropy of an ideal gas depends upon its
a. Pressure
b. Temperature
c. Both A and B
d. Neither A nor B

Both A and B

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At equilibrium condition, the chemical potential of a material in different phases in contact with each other is equal. The chemical potential for a real gas (µ) is given by (where, µ° = standard chemical potential at unit fugacity (f° = 1 atm) and the gas behaves ideally).
a. µ° + RT ln f
b. µ° + R ln f
c. µ° + T ln f
d. µ° + (R/T) ln f

µ° + RT ln f

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Partial molal quantities are important in the study of
a. Ideal gases
b. Ideal solutions
c. Non-ideal mixtures
d. A pure component

Non-ideal mixtures

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For organic compounds, group condition method can be used for the estimation of
a. Critical properties
b. Specific gravity
c. Specific volume
d. Thermal conductivity

Critical properties

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The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2 (where, T1>T2) is given by (T1-T2)/T1. The coefficient of performance (COP) of a Carnot heat pump operating between T1 and T2 is given by
a. T1/(T1-T2)
b. T2/(T1-T2)
c. T1/T2
d. T2/T1

T1/(T1-T2)

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Internal energy of an element at 1 atm and 25°C is ____ kcal/kg-mole.

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At the critical point of a substance
a. The surface tension vanishes
b. Liquid and vapour have the same density
c. There is no distinction between liquid and vapour phases
d. All of the above

All of the above

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In a P-V diagram (for an ideal gas), an isothermal curve will coincide with an adiabatic curve (through a point), when
a. Cp < Cv
b. Cp = Cv
c. Cp > Cv
d. Cp ≥ Cv

Cp = Cv

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The shape of T-S diagram for Carnot Cycle is a
a. Rectangle
b. Rhombus
c. Trapezoid
d. Circle

Rectangle

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With increase in compression ratio, the efficiency of
the otto engine
a. Increases
b. Decreases
c. Remains constant
d. Increases linearly

Increases

η = 1 - 1/r^(k-1)

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What is the degree of freedom for a system comprising liquid water equilibrium with its vapour?

df = N (component) - π (phase) - r (reaction) + 2

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____ functions are exemplified by heat and work. a. Path b. Point c. State d. None of these

Path

A two stage compressor is used to compress an ideal gas. The gas is cooled to the initial temperature after each stage. The intermediate pressure for the minimum total work requirement should be equal to the ____ mean of the P1 and P2 (where, P1 and P2 are initial and final pressures respectively. a. Logarithmic b. Arithmetic c. Geometric d. Harmonic

geometric

Helmholtz free energy (A) is defined as a. A = H − TS b. A = E − TS c. A = H + TS d. None of these

A = E - TS | E is usually U (internal energy)

Gibbs free energy (F) is defined as a. F = E − TS b. F = H − TS c. F = H + TS d. F = E + TS

F = H - TS | F is usually G (Gibbs energy)

A system is said to be at equilibrium if the entropy of the system has reached ____ value.

Maximum

In the reaction, C + O2 → CO2; ∆H = −94 kcal. What is the heat content (enthalpy) of O2?

Zero

The Maxwell relation derived from the differential expression for the Helmholtz free energy (dA) is a. (∂T/∂V)S = - (∂P/∂S)V b. (∂S/∂P)T = - (∂V/∂T)P c. (∂V/∂S)P = (∂T/∂P)S d. (∂S/∂V)T = (∂P/∂T)V

(∂S/∂V)T = (∂P/∂T)V

Which of the following processes can not be made reversible even under ideal condition of operation? a. Free expansion of a gas b. Compression of air in a compressor c. Expansion of steam in a turbine d. All of the above

Free expansion of a gas

Heat is added at constant pressure in an ideal ____ cycle. a. Stirling b. Brayton c. Rankine d. Both B and C

Both B and C

Heat is added at constant temperature in an ideal ____ cycle. a. Stirling b. Brayton c. Rankine d. Both B and C

Stirling

The standard state of a gas (at a given temperature) is the state in which fugacity is equal to a. Unity b. Activity c. Both A and B d. Neither A nor B

Both A and B

For a constant volume process ____ by the system is used only to increase the internal energy. a. Heat absorbed b. Work done c. Both A and B d. Neither A nor B

Heat absorbed

Which of the following is not a common refrigerant? a. Freon-12 b. Ethylene c. Ammonia d. Carbon Dioxide

Ethylene

Which of the following is not a reversible process? a. Expansion of an ideal gas against constant pressure b. Atmospheric pressure vaporization of water at 100°C c. Solution of NaCl in water at 50°C d. None of these

Solution of NaCl in water at 50°C

For spontaneous changes in an isolated system (S = entropy) a. Ds = 0 b. Ds < 0 c. Ds > 0 d. Ds = constant

dS > 0

A gas performs the maximum work, when it expands a. Non-uniformly b. Adiabatically c. Isobarically d. Isothermally

Isobarically

Degree of freedom of a system consisting of a gaseous mixture of H2 and NH3 will be

3 | df = N - π - r + 2

A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system a. Its internal energy (U) decreases and its entropy (S) increases b. U and S both decreases c. U decreases but S is constant d. U is constant but S decreases

U and S both decreases

The expression for entropy change given by, ∆S = −nR ln P2/P1, holds good for a. Expansion of a real gas b. Reversible isothermal volume change c. Heating of an ideal gas d. Cooling of a real gas

Reversible isothermal volume change

For any system, what is the minimum number of degrees of freedom?

Which of the following is not a unit of the equilibrium constant Kp? (where, ∆x = number of moles of products - number of moles of reactants) a. (atm)^∆x, when ∆x is negative b. (atm)^∆x, when ∆x is positive c. Dimensionless, when ∆x = 0 d. (atm)^∆(x²), when ∆x > 0

(atm)^∆(x²), when ∆x > 0

Equilibrium constant of a reaction varies with the a. Initial concentration of the reactant b. Pressure c. Temperature d. None of these

Temperature

Which of the following will increase the volume of a real gas by four times? a. Doubling the absolute temperature as well as pressure of the gas b. Reducing pressure to one fourth at constant temperature c. Reducing temperature to one fourth at constant pressure d. Reducing the temperature to half and doubling the pressure

Reducing pressure to one fourth at constant temperature

The eccentric factor of a material, ‘ω’ is defined as ω = − log10(Pr^sat)Tr^-1 − 1 = 0.7, where Pr^sat = reduced vapor pressure, Tr = reduced temperature. The value of accentric factor is always

< 1

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

1 | df = N - π - r + 2

“A solute distributes itself between two non-miscible solvents in contact with each other in such a way that, at a constant temperature, the ratio of its concentrations in two layers is constant, irrespective of its amount.” This is

the distribution law

What is the number of degrees of freedom for liquid water in equilibrium with a mixture of nitrogen and water vapor?

2 | df = N - π - r + 2

The first law of thermodynamics is a restatement of the law of conservation of

Energy

Entropy of the system decreases, when a. Snow melts into water b. A gas expands spontaneously from high pressure to low pressure c. Water is converted into ice d. Both B and C

Both B and C

The second law of thermodynamics states that a. The energy change of a system undergoing any reversible process is zero. b. It is not possible to transfer heat from a lower temperature to a higher temperature. c. The total energy of a system and surrounding remains the same. d. None of the above.

None of the above.

If we increase the pressure on a substance (which is at its triple point), then the triple point

Remains unchanged

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

Isothermal

The fusion of a crystalline solid at its melting point to form a liquid at the same temperature is accompanied by a. Decrease in enthalpy corresponding to evolution of heat b. Decrease of entropy c. Increase in enthalpy corresponding to absorption of heat d. No change in enthalpy

Increase in enthalpy corresponding to absorption of heat

The minimum number of phases that can exist in a system is

Extensive properties of a thermodynamic system can depend upon the ____ of the system.

mass

Van Laar equation deals with the activity coefficients in

binary solutions

1m3 of an ideal gas at 500K and 1000 kPa expands reversibly to 5 times its initial volume in an insulated container. If the specific heat capacity (at constant pressure) of the gas is 21 J/mol-K, the final temperature will be

274 K

When pressure is applied on the system, ice ↔ water, then a. Equilibrium can not be established b. More ice will be formed c. More water will be formed d. Evaporation of water will take place

More water will be formed

If different processes are used to bring about the same chemical reaction, the enthalpy change is same for all of them. This is ____ law.

Hess's

If the atmospheric temperature and dew point are nearly equal, then the relative humidity is

Almost 100%

First law of thermodynamics deals with the

Direction of energy transfer

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

same

COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about

3.5

The number of degree of freedom for an azeotropic mixture of ethanol and water in vapour-liquid equilibrium, is

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

minus infinity

Out of the following refrigeration cycles, which one has the minimum COP (Coefficient of Performance)? a. Air cycle b. Carnot cycle c. Ordinary vapour compression cycle d. Vapour compression with a reversible expansion engine

Air cycle

At absolute zero temperature, all substances have the same a. Heat capacity b. Crystalline structure c. Entropy d. None of these

Heat capacity

The expression, ∆G = nRT ln P2/P1, gives the free energy change a. With pressure changes at constant temperature b. Under reversible isothermal volume change c. During heating of an ideal gas d. During cooling of an ideal gas

With pressure changes at constant temperature

The thermodynamic law, PV^γ = 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

Free expansion of an ideal gas

Entropy change of the reaction, H2O (liquid) → H2O (gas), is termed as the enthalpy of

vaporisation

Specific ____ does not change during a phase change (e.g., sublimation, melting, vaporization etc.).

Gibbs free energy

For an ideal gas, the activity coefficient is

unity at all pressure

For an isothermal process, the internal energy of a gas

remains unchanged

If two gases have same reduced temperature and reduced pressure, then they will have the same a. Volume b. Mass c. Critical temperature d. None of these

None of these | accentric factor could be different

Gibbs phase rules finds application when heat transfer occurs by

condensation

There is a change in ____ during the phase transition. a. Volume b. Pressure c. Temperature d. All of the above

Volume

At a given temperature, the volume of a gas dissolved in a solvent ____ with increase in pressure.

remain unchanged

Chemical engineering thermodynamics is concerned with the ____ in/of chemical processes.

energy transformation from one form to the another

A gas can be liquified by pressure alone only when its temperature is ____ its critical temperature.

less than or equal to

In case of a close thermodynamic system, there is ____ across the boundaries.

no mass transfer but heat transfer

Clausius – Clayperon equation is applicable to ____ equilibrium processes. a. Solid-vapor b. Solid-liquid c. Liquid-vapor d. All of the above

All of the above | However, SLE is not applicable due to small volume changes.

In any spontaneous process, the ____ free energy decreases.

Both Helmholtz and Gibbs

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

below

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

Second

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

Zeroth

A refrigerator works on the principle of ____ law of thermodynamics.

Second

Near their critical temperature, all gases occupy volumes ____ that of the ideal gas

less than

An isolated system can exchange ____ with its surroundings.

neither matter nor energy

The coefficient 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

None of these

Domestic refrigerators usually work on the ____ refrigeration cycle.

absorption

At absolute zero temperature, the ____ of the gas is zero.

volume

The melting point of paraffin wax (which contracts on solidification) ____ with pressure rise.

increases

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

Simultaneous heating and expansion of an ideal gas

On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (𝜕P/𝜕V)S and the slope of the reversible isothermal line (𝜕P/𝜕V)T are related as (where, γ = Cp/Cv). a. (𝜕P/𝜕V)S = (𝜕P/𝜕V)T b. (𝜕P/𝜕V)S = [ (𝜕P/𝜕V)T ]^γ c. (𝜕P/𝜕V)S = γ (𝜕P/𝜕V)T d. (𝜕P/𝜕V)S = (1/γ) (𝜕P/𝜕V)T

(𝜕P/𝜕V)S = γ (𝜕P/𝜕V)T

Trouton’s ratio is given by (where λb = molal heat of vaporization of a substance at its normal boiling point, kcal/kmol Tb = normal boiling point, °K.) a. λb/Tb b. Tb/λb c. √(λb/Tb) d. √(Tb/λb)

λb/Tb

Isentropic process means a constant ____ process.

Entropy

Process and Solution Thermodynamics (Archived) Flashcards

(This deck is archived.) Concepts and calculation techniques necessary for thermodynamic analyses of processes and mixtures; physical chemistry concepts are also included.