Thermodynamics Part 2 Flashcards

1
Q

Enthalpy ‘H’ is defined as
H = E - PV
H = F - TS
H - E = PV
none of these

A

H - E = PV

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2
Q

One ton of refrigeration is defined as the heat rate corresponding to melting of one ton of ice in one
hour
day
minute
second

A

day

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3
Q

__________ functions are exemplified by heat and work.
Path
Point
State
none of these

A

Path

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4
Q

In an irreversible process
Tds = dE - dW = 0
dE - dW - Tds = 0
Tds - dE + dW< 0
Tds - dT + dW< 0

A

Tds - dE + dW< 0

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5
Q

What is the number of degree of freedom for a system of two miscible non-reacting species in vapor-liquid equilibrium forming an azeotrope ?
3
2
1
0

A

1

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6
Q

The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is
R loge 4
R log10 4
Cv log10 4
Cv loge 4

A

R loge 4

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7
Q

PVgamma = Constant (where, gamma = Cp/Cv) is valid for a/an __________ process.
isothermal
isentropic
isobaric
adiabatic

A

adiabatic

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8
Q

Claude gas liquefaction process employs cooling
at constant pressure.
by throttling.
by expansion in an engine.
none of these.

A

by expansion in an engine.

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9
Q

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

A

Reducing pressure to one fourth at constant temperature.

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10
Q

Pick out the wrong statement.
A refriferation cycle violates the second law of thermadynamics.
Refrigeration cycle is normally represented by a temperature vs. entropy plot.
In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases.
One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW.

A

A refriferation cycle violates the second law of thermadynamics.

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11
Q

The equation, PV = nRT, is best obeyed by gases at
low pressure & high temperature.
high pressure & low temperature.
low pressure & low temperature.
none of these.

A

low pressure & high temperature.

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12
Q

Internal energy of an element at 1 atm and 25 C is __________ kcal/kg.mole.
0
273
25
none of these

A

0

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13
Q

Which of the following liquid metals has the highest thermal conductivity ?
Molten sodium
Molten lead
Mercury
Molten potassium

A

Molten sodium

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14
Q

Which of the following has the least thermal efficiency ?
Steam engine
Carnot engine
Diesel engine
Otto engine

A

Steam engine

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15
Q

Joule-Thomson Co-efficient at any point on the inversion curve is
infinity
+ ve
0
-ve

A

0

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16
Q

Pick out the wrong statement.
The values of (1) 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.

A

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

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17
Q

Number of components (C), phase (P) and degrees of freedom (F) are related by Gibbs phase rule as
P + F - C = 2
C = P - F + 2
F = C - P - 2
P = F - C - 2

A

P + F - C = 2

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18
Q

The value of Cp & Cv respectively for monoatomic gases in Kcal/kg Mole . K are
5 & 3
3.987 & 1.987
1.987 & 0.66
0.66 & 1.987

A

5 & 3

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19
Q

(aT/aP)H is the mathematical expression for (a = partial differential)
specific heat at constant pressure (Cp).
specific heat at constant volume (Cv).
Joule-Thompson co-efficient.
none of these.

A

Joule-Thompson co-efficient.

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20
Q

In case of a close thermodynamic system, there is __________ across the boundaries.
no heat and mass transfer
no mass transfer but heat transfer
mass and energy transfer
none of these

A

no mass transfer but heat transfer

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21
Q

During a reversible isothermal expansion of an ideal gas, the entropy change is
+ve
0
-ve
infinity

A

+ve

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22
Q

As the temperature is lowered towards the absolute zero, the value of (a(delta-F))/aT, then approaches
unity
zero
that of the heat of reaction
infinity

A

zero

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23
Q

Which of the following is not affected by temperature changes ?
Fugacity
Activity co-efficient
Free energy
None of these

A

None of these

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24
Q

For an ideal gas, the activity co-efficient is
directly proportional to pressure.
inversely proportional to pressure.
unity at all pressures.
none of these.

A

unity at all pressures.

ideal activity unity

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25
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. ideal real isotonic none of these
ideal
26
Generation of heat by friction is an example of a/an __________ change. isothermal irreversible adiabatic reversible
irreversible
27
A domestic refrigerator has a/an __________ cooled condenser. water air evaporative gas
air
28
The compressibility factor of a gas is given by (where, V1 = actual volume of the gas V2 = gas volume predicted by ideal gas law ) V1/V2 V2/V1 V1-V2 V1.V2
V1/V2
29
If we increase the pressure on a substance (which is at its triple point), then the triple point increases decreases remains unchanged may increase or decrease ; depends on the substance
remains unchanged
30
In an ideal refrigeration cycle, the change in internal energy of the fluid is +ve -ve 0 either of the above three ; depends on the nature of refrigerant.
0
31
Free energy decreases in all spontaneous (or irreversible) processes. change during a spontaneous process has a negative value. remains unchanged in reversible processes carried at constant temperature and pressure. all of these
all of these
32
"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 Kirchoff's Lavoisier and Laplace none of these
Hess's
33
Fugacity is a measure of the escaping tendencies of the same substance in different phases of a system. relative volatility of a mixture of two miscible liquids. behaviour of ideal gases. none of these.
escaping tendencies of the same substance in different phases of a system.
34
The quantitative effect of temperature on chemical equilibrium is given by the Vant-Hoff equation. Le-Chatelier's principle. Arhenius equation. none of these.
Vant-Hoff equation.
35
For an irreversible process involving only pressure-volume work (dF)T, p <0 (dF)T, p = 0 (dF)T, p > 0 (dA)T, v >0
(dF)T, p <0
36
Ideal refrigeration cycle is same as Carnot cycle. same as reverse Carnot cycle. dependent on the refrigerant's properties. the least efficient of all refrigeration processes.
same as reverse Carnot cycle.
37
The following heat engine produces power of 100000 kW. The heat engine operates between 800 K and 300 K. It has a thermal efficiency equal to 50% of that of the Carnot engine for the same temperature. The rate at which heat is absorbed from the hot reservoir is 100, 000 kW 160, 000 kW 200, 000 kW 320, 000 kW
320, 000 kW
38
The enthalpy change when ammonia gas is dissolved in water is called the heat of solution formation dilution combustion
solution
39
The value of Joule-Thomson co-efficient, in case where cooling occurs after the throttling process is 0 infinity +ve -ve
+ve
40
The specific heat of saturated water vapour at 100 C is infinity -ve 0 +ve
-ve
41
For a multicomponent system, the term chemical potential is equivalent to the molal concentration difference. molar free energy. partial molar free energy. molar free energy change.
partial molar free energy.
42
The change in Gibbs freee energy for vaporisation of a pure substance is positive negative zero may be positive or negative
zero
43
Critical compressibility factor for all substances are more or less constant (vary from 0.2 to 0.3). vary as square of the absolute temperature. vary as square of the absolute pressure. none of these.
are more or less constant (vary from 0.2 to 0.3).
44
What is the degree of freedom for two mis-cible (non-reacting) substances in vapor-liquid equilibrium forming an azeotrope ? 0 1 2 3
2
45
For a given substance at a specified temperature, activity is __________ to fugacity. directly proportional inversely proportional equal none of these
directly proportional
46
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.
enhanced COP.
47
For water at 300 C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm^3 and that in vapour phase in 391.1 cm^3.Fugacity of water (in kPa) at 9000 kPa will be 6738.9 6753.5 7058.3 9000
6753.5
48
As the temperature is lowered towards the absolute zero, the value of the quantity approaches zero unity infinity none of these
zero
49
If the heat of solution of an ideal gas in a liquid is negative, then its solubility at a given partial pressure varies with the temperature as solubility increases as temperature increases. solubility increases as temperature decreases. solubility is independent of temperature. solubility increases or decreases with temperature depending on the Gibbs free energy change of solution.
solubility increases as temperature decreases.
50
In case of a reversible process (following pv^n = constant), work obtained for trebling the volume (v1 = 1 m^3 and v2 3 m^3 ) is max imum, when the value of 'n' is 0 1 y = 1.44 1.66
0
51
The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is less more same dependent on climatic conditions
less
52
The unit of fugacity is the same as that of the pressure temperature volume molar concentration
pressure
53
Filling of gas from a high pressure cylinder into small bottles is an example of a/an __________ process. equilibrium adiabatic steady unsteady
unsteady
54
A large iceberg melts at the base, but not at the top, because of the reason that ice at the base contains impurities which lowers its melting point. due to the high pressure at the base, its melting point reduces. the iceberg remains in a warmer condition at the base. all of these
due to the high pressure at the base, its melting point reduces.
55
At the critical point of a substance the surface tension vanishes. liquid and vapour have the same density. there is no distinction between liquid and vapour phases. all of these
all of these
56
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, delta- S1 and delta- SR are the entropy changes of the system for the irreversible and reversible processes respectively) delta- S1 is always < delta- SR delta- S1 is sometimes > delta- SR delta- S1 is always > delta- SR delta- S1 is always = delta- SR
delta- S1 is always > delta- SR
57
What is the value of Joule-Thomson co-efficient for an ideal gas ? +ve -ve 0 infinity
0
58
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 P1 and P2.(where, P1 and P2 are initial and final pressures respectively) logarithmic arithmetic geometric harmonic
geometric
59
γ = specific heat ratio of an ideal gas is equal to Cp/Cv Cp/(CP-R) 1 + (R/CV) all of these
all of these
60
Consider the process A & B shown in the figure given below (1) In this case, it is possilbe that both the processes are adiabatic. both the processes are isothermal. process A is isothermal while B is adiabatic. process A is adiabatic while B is isothermal.
process A is isothermal while B is adiabatic.
61
Gibbs free energy of a pure fluid approaches __________ as the pressure tends to zero at constant temperature. infinity minus infinity zero none of these
minus infinity
62
As the entropy of the universe is increasing, day by day, the work producing capacity of a heat engine is not changed decreasing increasing data sufficient, can't be predicted
decreasing
63
An irreversible process is the analog of linear frictionless motion in machines. is an idealised visualisation of behaviour of a system. yields the maximum amount of work. yields an amount of work less than that of a reversible process.
yields an amount of work less than that of a reversible process.
64
The expression for the work done for a reversible polytropic process can be used to obtain the expression for work done for all processes, except reversible __________ process. isobaric isothermal adiabatic none of these
isothermal
65
Free energy change of mixing two liquid substances is a function of the concentration of the constituents only. quantities of the constituents only. temperature only. all of these
all of these
66
Pick out the wrong statement. System (of partially miscible liquid pairs), in which the mutual solubility increases with rise in temperature, are said to possess an upper consolute temperature. Systems, in which the mutual solubility increases with decrease in temperature, are said to possess lower consolute temperature. Nicotine-water system shows both an upper as well as a lower consolute temperature, implying that they are partially miscible between these two limiting temperatures. none of these
none of these
67
The total change in the enthalpy of a system is independent of the number of intermediate chemical reactions involved. pressure and temperature. state of combination and aggregation in the beginning and at the end of the reaction. none of these.
number of intermediate chemical reactions involved.
68
Number of phases in a colloidal system are 1 2 3 4
2
69
Free energy changes for two reaction mechanism 'X' and 'Y are respectively - 15 and - 5 units. It implies that X is slower than Y faster than Y three times slower than Y three times faster than Y
faster than Y
70
Vapour which is at a pressure smaller than the saturation pressure for the temperature involved is called a __________ vapour. superheated desuperheated non-condensable none of these
superheated
71
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.) μ + RT ln f μ + R lnf μ + T lnf μ + R/T lnf
μ + RT ln f
72
The kinetic energy of gas molecule is zero at 0 C 273 C 100 C -273 C
-273 C
73
Which of the following is not an intensive property ? Volume Density Temperature Pressure
Volume
74
The necessary and sufficient condition for equilibrium between two phases is the concentration of each component should be same in the two phases. the temperature of each phase should be same. the pressure should be same in the two phases. the chemical potential of each component should be same in the two phases.
the chemical potential of each component should be same in the two phases.
75
Specific volume of an ideal gas is equal to its density. the reciprocal of its density. proportional to pressure. none of these.
the reciprocal of its density.
76
Pick out the extensive property out of the following. Surface tension Free energy Specific heat Refractive index
Free energy
77
Entropy change of the reaction, H2O(liquid) H2O(gas), is termed as the enthalpy of solution vaporisation formation formation
vaporisation
78
Which law of the thermodynamics provids basis for measuring the thermodynamic property ? First law Zeroth law Third law Second law
Zeroth law
79
Gibbs free energy per mole for a pure substance is equal to the latent heat of vaporisation chemical potential molal boiling point heat capacity
chemical potential
80
Gibbs free energy at constant pressure and temperature under equilibrium conditions is infinity 0 maximum minimum
minimum
81
With increase in pressure (above atmospheric pressure), the Cp of a gas increases decreases remains unchanged first decreases and then increases
increases
82
A change in state involving a decrease in entropy can be spontaneous, only if it is exothermic. it is isenthalpic. it takes place isothermally. it takes place at constant volume.
it is exothermic.
83
Joule-Thomson co-efficient which is defined as, n = (aT/aP)H = (1/Cp)(aH/aT)P , changes sign at a temperature known as inversion temperature. The value of Joule-Thomson co-efficient at inversion temperature is 0 infinity +ve -ve
0
84
__________ calorimeter is normally used for measuring the dryness fraction of steam, when it is very low. Bucket Throttling Separating A combination of separating & throttling
A combination of separating & throttling
85
The amount of heat required to decompose a compound into its elements is __________ the heat of formation of that compound from its elements. less than more than same as not related to
same as
86
For a constant volume process dE = CpdT dE = CvdT dQ = dE + pdV dW = pdV
dE = CvdT
87
In case of the decomposition of hydroiodic acid (2HI <~> H2 + I2), addition of H2 (at equilibrium condition) will increase the partial pressure of I2. decrease the partial pressure of HI. diminish the degree of dissociation of HI. none of these.
diminish the degree of dissociation of HI.
88
In any spontaneous process, the __________ free energy decreases. Helmholtz Gibbs both a & b neither 'a' nor 'b'
both a & b
89
The equation DU = Tds - PdV is applicable to infinitesimal changes occuring in an open system of constant composition. a closed system of constant composition. an open system with changes in composition. a closed system with changes in composition.
a closed system with changes in composition.
90
Heat is added at constant temperature in an ideal __________ cycle. Stirling Brayton Rankine none of these
Stirling ## Footnote stirling - heat added at constant temp
91
Pick out the correct equation relating 'F' and 'A'. F = A + PV F = E + A F = A - TS F = A + TS
F = A + PV
92
In a reversible process Tds = dE + dW dE - dW = Tds dW - dE = Tds Tds - dW + dE >0
Tds = dE + dW
93
Cv for an ideal gas does not depend upon temperature. is independent of pressure only. is independent of volume only. is independent of both pressure and volume.
is independent of both pressure and volume.
94
In a homogeneous solution, the activity co-efficient of a component depends upon the pressure composition temperature all of these
all of these
95
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.
An isometric process is a constant pressure process.
96
With increase in compression ratio, the efficiency of the otto engine increases decreases remains constant increases linearly
increases
97
The chemical potential of any constituent of an ideal solution depends on the __________ of the solution. temperature pressure composition all of these
all of these
98
Fugacity and pressure are numerically equal, when the gas is in standard state at high pressure at low temperature in ideal state
in ideal state ## Footnote ideal - equal fugacity and pressure
99
Refrigerants commonly used for domestic refrigerators are ethyl chloride or methyle chloride freon-12 propane NH3 or CO2.
ethyl chloride or methyle chloride
100
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.
temperature of the heat reservoir to which a Carnot engine rejects no heat.
101
Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.). entropy internal energy enthalpy Gibbs free energy
Gibbs free energy
102
Heat of formation of an element in its standard state is 0 < 0 > 0 a function of pressure
0
103
The equation relating E, P, V and T which is true for all substanes under all conditions is given by (∂E/∂V)T = T (∂P/∂T)H - P .This equation is called the Maxwell's equation. thermodynamic equation of state. equation of state. Redlich-Kwong equation of state.
thermodynamic equation of state.
104
For an exothremic reaction only enthalpy change (delta-H) is negative. only internal energy change (delta-E) is negative. both delta-H and delta-E are negative. enthalpy change is zero.
both delta-H and delta-E are negative.
105
Pick out the wrong statement. An ideal liquid or solid solution is defined as one in which each component obeys Raoult's law. If Raoult's law is applied to one component of a binary mixture ; Henry's law or Raoult's law is applied to the other component also. Henry's law is rigorously correct in the limit of infinite dilution. none of these.
none of these.
106
The shape of T-S diagram for Carnot Cycle is a rectangle rhombus trapezoid circle
rectangle
107
For an isothermal process, the internal energy of a gas increases decreases remains unchanged data insufficient, can't be predicted
remains unchanged
108
In the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process. isothermal isobaric polytropic adiabatic
isothermal
109
For the gaseous phase chemical reaction, C2H4(g) + H2O(g) <~> C2H5OH(g), the equilibrium conversion does not depend on the steam to ethylene ratio. temperature. pressure. none of these.
none of these.
110
The first law of thermodynamics is a statement of conservation of heat momentum energy work
energy
111
"Dry ice" is moisture free ice solid helium solid carbon dioxide none of these
solid carbon dioxide
112
Which of the following non-flow reversible compression processes require maximum work ? Adiabatic process Isothermal process Isobaric process All require same work
Adiabatic process
113
Pick out the correct statement. A real gas on expansion in vacuum gets heated up. An ideal gas on expansion in vacuum gets cooled. An ideal gas on expansion in vacuum gets heated up. A real gas on expansion in vacuum cools down whereas ideal gas remains unaffected.
A real gas on expansion in vacuum cools down whereas ideal gas remains unaffected.
114
"When a system in equilibrium is subjected to a change in temperature, pressure or concentration, the equilibrium is displaced in a direction which tends to undo the effect of the change." This is called the Le-Chatelier principle. Kopp's rule. law of corresponding state. Arrehenius hypothesis.
Le-Chatelier principle.
115
Sound waves propagation in air exemplifies an __________ process. adiabatic isothermal isometric none of these
adiabatic
116
For equilibrium process (i.e. reversible) in an isolated system ds = 0 ds < 0 ds > 0 ds = Constant
ds = 0
117
The partial molar enthalpy of a component in an ideal binary gas mixture of composition Z, at a temperature T and pressure P, is a function only of T T and P T, P and Z T and Z
T and P
118
With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure increases decreases remains same decreases linearly
increases
119
For an ideal gas, the enthalpy increases with rise in pressure. decreases with rise in pressure. is independent of pressure. is a path function.
is independent of pressure.
120
Efficiency of a heat engine working on Carnot cycle between two temperature levels depends upon the two temperatures only. pressure of working fluid. mass of the working fluid. mass and pressure both of the working fluid.
two temperatures only.
121
In Joule-Thomson porous plug experiment, the enthalpy does not remain constant. entire apparatus is exposed to surroundings. temperature remains constant. none of these.
enthalpy does not remain constant.
122
A Carnot cycle consists of the following steps : Two isothermals and two isentropics. Two isobarics and two isothermals. Two isochorics and two isobarics. Two isothermals and two isochorics.
Two isothermals and two isentropics.
123
For a cyclic process, a fixed ratio between heat and work always exists may exist never exists is difficult to predict
always exists
124
Which of the following is not a common refrigerant ? Freon-12 Ethylene Ammonia Carbon dioxide
Ethylene
125
The most important application of distribution law is in evaporation liquid extraction drying distillation
liquid extraction
126
Pick out the correct statement. Entropy and enthalpy are path functions. In a closed system, the energy can be exchanged with the surrounding, while. matter can not be exchanged. All the natural processes are reversible in nature. Work is a state function.
All the natural processes are reversible in nature.
127
In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13 C and 37 C respetively, the Carnot COP will be 5.2 6.2 0.168 data insufficient, can't be found out
5.2
128
Gibbs free energy of mixing at constant pressure and temperature is always 0 ∞ +ve -ve
-ve
129
The compressibility factor for an ideal gas is 1. Its value for any other real gas is 1 < 1 > 1 either (b) or (c), depends on the nature of the gas
either (b) or (c), depends on the nature of the gas
130
If two gases have same reduced temperature and reduced pressure, then they will have the same volume mass critical temperature none of these
none of these
131
Which of the following is an extensive property of a system ? Heat capacity Molal heat capacity Pressure Concentration
Heat capacity
132
The reaction A (l) -> R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The number of degrees of freedom are 1 2 3 0
1
133
Cp - Cv = R is valid for __________ gases. ideal all very high pressure very low temperature
ideal
134
At a given temperature, the volume of a gas dissolved in a solvent __________ with increase in pressure. increases decreases remains unchanged may increase or decrease; depends on the gas
remains unchanged
135
Which is an example of closed system ? Air compressor Lquid cooling system of an automobile Boiler None of these
Lquid cooling system of an automobile
136
Melting of wax is accompanied with __________ in entropy. increase decrease no change none of these
increase
137
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. (1) The net work done during the complete cycle is given by the area covered by P1ACBP2P1 ACBB1A1A ACBDA ADBB1A1A
ACBDA
138
Work done in case of free expansion is indeterminate zero negative none of these
zero
139
Chemical potential (an intensive property) of a substance is a force that drives the chemical system to equilibrium and is equal to its partial molar properties. The reatio of chemical potential to free energy of a pure substance at oconstant temperature and pressure is 0 1 infinity none of these
1
140
During adiabatic expansion of gas pressure remains constant. pressure is increased. temperature remains constant. none of these.
none of these.
141
Which of the following has the minimum value of COP for a given refrigeration effect? Reverse Carnot cycle. Ordinary vapour-compression cycle. Vapour-compression process with a reversible expansion engine. Air refrigeration cycle.
Air refrigeration cycle.
142
__________ decreases during adiabatic throttling of a perfect gas. Entropy Temperature Enthalpy Pressure
Pressure ## Footnote adibatic throttling pressure decrease
143
Pick out the wrong statement. Minimum number of degree of freedom of a system is zero. Degree of freedom of a system containing a gaseous mixture of helium, carbon dioxide and hydrogen is 4. For a two phase system in equilibrium made up of four non-reacting chemical species, the number of degrees of freedom is 4. Enthalpy and internal energy change is zero during phase change processes like melting, vaporisation and sublimation.
Enthalpy and internal energy change is zero during phase change processes like melting, vaporisation and sublimation.
144
Tea kept in a thermos flask is vigorously shaken. If the tea is considered as a system, then its temperature will increase decrease remain unchanged first fall and then rise.
increase
145
Change of heat content when one mole of compound is burnt in oxygen at constant pressure is called the calorific value heat of reaction heat of combustion heat of formation
heat of combustion
146
Clausius - Clayperon equation is applicable to __________ equilibrium processes. solid-vapor solid-liquid liquid-vapor all of these
all of these
147
In which of the following reaction equilibria, the value of equilibrium constant Kp will be more than is Kc ? 2HI <~> H2 + I2 N2O4 <~> 2NO2 2SO2 + O2 <~> 2SO3 none of these
N2O4 <~> 2NO2
148
After throttling, gas temperature decreases increases remains same may increase or decrease ; depends on the nature of the gas
decreases
149
The chemical potential for a pure substance is __________ its partial molal free energy. more than less than equal to not related to
equal to
150
When liquid and vapour phase of multi-component system are in equilibrium (at a given temperature and pressure), then chemical potential of each component is same in both the phases. zero in both the phases. more in vapour phase. more in liquid phase.
same in both the phases.
151
COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about 0.5 3.5 4.5 8.5
3.5 ## Footnote 3.5 COPref 1kW
152
The number of degrees of freedom for a mixture of ice and water (liquid) are 2 3 1 0
1
153
On opening the door of an operating refrigerator kept in a closed room, the temperature of the room will increase decrease remain same increase in summer and will decrease in winter
increase
154
Domestic refrigerator usually works on the __________ refrigeration cycle. Carnot air absorption vapour-ejection
absorption
155
Gibbs-Duhem equation states that n1du1 + n2du2 + ....njduj = 0, for a system of definite composition at constant temperature and pressure. applies only to binary systems. finds no application in gas-liquid equilibria involved in distillation. none of these
states that n1du1 + n2du2 + ....njduj = 0, for a system of definite composition at constant temperature and pressure.
156
Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is 1 4 2 3
2
157
The internal energy of a gas obeying P (V - b) RT (where, b is a positive constant and has a constant Cv), depends upon its pressure volume temperature all of these.
temperature
158
"When a gas is expanded from high pressure region to low pressure region ; temper -ature change occurs". This phenomenon is related to the Gibbs-Duhem equation Gibbs-Helmholtz equation Third law of thermodynamics Joule-Thomson effect
Joule-Thomson effect
159
The internal energy of an ideal gas does not change in a reversible __________ process. isothermal adiabatic isobaric isometric
isothermal
160
A/an __________ system is exemplified by a vessel containing a volatile liquid in contact with its vapor. isolated closed open none of these
open
161
In a P-V diagram (for an ideal gas), an isothermal curve will coincide withan adiabatic curve (through a point), when Cp < Cv Cp = Cv Cp > Cv C >= Cv
Cp = Cv
162
For an ideal gas, the chemical potential is given by RT dlnP R dlnP R dlnf none of these
RT dlnP
163
Two substances are in equilibrium in a reversible chemical reaction. If the concentration of each substance is doubled, then the value of the equilibrium constant will be same doubled halved one fourth of its original value
same
164
In the ammonia synthesis reaction, N2 + 3H2 <~> 2NH3 + 22.4 kcal, the formation of NH3 will be favoured by high temperature. low pressure. low temperature only. both low temperature and high pressure.
both low temperature and high pressure.
165
Entropy change for an irreversible isolated system is infinity 0 < 0 > 0
> 0
166
Heat requirement for decomposition of a compound into its elements is __________ that is evolved during the formation of that compound from its elements. the same less than greater than different than
the same
167
The unit of equilibrium constant of a chemical reaction is the same as that of molar concentration temperature internal energy none of these
none of these
168
Which of the following equations is obtained on combining 1st and 2nd law of thermodynamics, for a system of constant mass? dE = Tds - PdV dQ = CvdT + PdV dQ = CpdT + Vdp Tds = dE - PdV
dE = Tds - PdV
169
The Joule-Thomson co-efficient is defined as (aT/aP)H. Its value at the inversion point is infinity 1 0 -ve
0
170
Fugacity of a component in an ideal gas mixture is euqal to the partial pressure of that component in the mixture. The fugacity of each component in a stable homogeneous solution at contant pressure and temperature __________ as its mole fraction increases. decreases decreases exponentially increases remains constant
increases