Chemical Engineering Thermodynamics Flashcards
1
Q
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.
2
Q
For a constant pressure reversible process, the enthalpy change (ΔH) of the system is
A
integ Cv.dT
3
Q
The work done in isothermal compression compared to that in adiabatic compression will be
A
more
4
Q
For organic compounds, group contribution method can be used for the estimation of
A
critical properties.
5
Q
A
Gibbs energy
6
Q
When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is
A
same in both the phases.
7
Q
Heat evolved/absorbed during conversion of a substance from one allotropic form to another is termed as the heat of
A
transition
8
Q
What happens in a reversible adiabatic compression ?
A
Heating occurs
9
Q
Sublimation temperature of dry ice (solid CO2) is __________ °C.
A
-78
10
Q
If atmospheric temperature and dew point are nearly equal, then the relative humidity is
A
almost 100%
11
Q
Entropy change in case of reversible adiabatic process is
A
zero
12
Q
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
same
13
Q
The efficiency of an Otto engine compared to that of a diesel engine, for the same compression ratio will be
A
more
14
Q
Mollier chart is a __________ plot.
A
enthalpy vs entropy
15
Q
Variation of equilibrium pressure with temperature for any two phases of a given substances is given by the __________ equation.
A
Clayperon
16
Q
Pick out the undesirable property for a good refrigerant.
A
high viscosity
17
Q
Isotherm on an enthalpy-concentration diagram, for an ideal solution will be a
A
straight line
18
Q
The fusion of a crystalline solid at its melting point to form a liquid at the same temperature is accompanied by
A
increase in enthalpy corresponding to absorption of heat.
19
Q
Melting of ice is an example of an __________ process.
A
isothermal
20
Q
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.
A
448
21
Q
Rotary lime kiln is an example of a/an __________ system.
A
open
22
Q
Heat of reaction is
A
dependent on both pressure and temperature.
23
Q
The expression, , is for the____of an ideal gas.
A
work done under isothermal condition
24
Q
What happens in a reversible adiabatic expansion process ?
A
Cooling takes place.
25
Degree of freedom of a system consisting of a gaseous mixture of H2 and NH3 will be
3
26
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, y = Cp/Cv)
(∂P/∂V)S = y(∂P/∂V)T
27
Pick out the wrong statement.
a. The net change in entropy in any reversible
cycle is always zero.
b. The entropy of the system as a whole in an
irreversible process increases.
c. The entropy of the universe tends to a
maximum.
d. The entropy of a substance does not
remain constant during a reversible
adiabatie change.
The entropy of a substance does not
remain constant during a reversible
adiabatie change.
28
Fugacity co-efficient of a substance is the ratio of its fugacity to
activity co-efficient
29
Dryness fraction of wet steam is defined as the ratio of mass of vapour in the mixture to the mass of mixture __________ calorimeter is not used for measuring the dryness fraction of steam.
Bomb
30
As the time is passing, entropy of the universe
is increasing
31
Which of the following processes can not be made reversible even under ideal condition of operation?
Free expansion of a gas.
32
The relation connecting the fugacities of various components in a solution with one another and to composition at constant temperature and pressure is called the __________ equation.
Gibbs-Duhem
33
Which of the following identities can be most easily used to verify steam table data for superheated steam.
(∂V/∂T)P = -(∂S/∂P)T
34
In the equation PVn = constant, if the value of n = y = Cp/Cv, then it represents a reversible __________ process.
isentropic
35
The ammonia synthesis reaction represented by N2 + 3H2 ⇌ 2NH3 ; ΔH = - 22.4 kcal, is
exothermic
36
With increase in temperature, the atomic heat capacities of all solid elements
increases
37
The temperature at the eutectic point of the system is the __________ temperature that can be attained in the system.
lowest
38
The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapour compression refrigeration system) is
more pronounced
39
Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg . K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is
superheated vapour.
40
An isentropic process is carried out at constant
volume
41
All gases except __________ shows a cooling effect during throttling process at atmospheric temperature and pressure.
hydrogen
42
High pressure steam is expanded adiabati-cally 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.
43
The necessary condition for phase equilibrium in a multiphase system of N components is that the
chemical potentials of a given component should be equal in all phases.
44
Compressibility factor-reduced pressure plot on reduced co-ordinates facilitates
use of only one graph for all gases.
45
Which of the following is not an intensive property ?
Internal energy
46
Pick out the wrong statement.
a. At constant pressure, solubility of a gas in
a liquid diminishes with rise in
temperature.
b. Normally, the gases which are easily liquified,
are more soluble in common solvents.
c. The gases which are capable of forming ions
in aqueous solution, are much more soluble in
water than in other solvents.
d. At constant pressure, solubility of a gas in a
liquid increases with rise in temperature.
At constant pressure, solubility of a gas in a liquid diminishes with rise in temperature.
47
Gibbs phase rule finds application, when heat transfer occurs by
condensation
48
Absorption/evolution of heat during conversion of a substance from one allotropic form to another is termed as the heat of
transition
49
Ideal gas law is applicable at
high T, low P
50
Reduced pressure of a gas is the ratio of its
pressure to critical pressure.
51
For a reversible process involving only pressure-volume work
(dF)T, p = 0
52
Air enters an adiabatic compressor at 300K. The exit temperature for a compression ratio of 3, assuming air to be an ideal gas (Y = Cp/Cv = 7/5) and the process to be reversible, is
300(32/7)
53
Entropy change for an irreversible process taking system and surrounding together is
> 0
54
In a homogeneous solution, the fugacity of a component depends upon the
All
55
For an incompressible fluid, the __________ is a function of both pressure as well as temperature.
enthalpy
56
An ideal monoatomic gas is taken round the cycle ABCDA as shown below in the P-V diagram (1) The work done during the cycle is
PV
57
One ton of refrigeration capacity is equivalent to the heat removal rate of
200 BTU/minute
58
What is the degree of freedom for a system comprising liquid water equilibrium with its vapour ?
1
59
Equilibrium constant of a reaction varies with the
temperature.
60
Third law of thermodynamics is concerned with the
value of absolute entropy.
61
Claude's liquefaction process employs the cooling of gases by
expansion in an engine
62
Gibbs free energy (F) is defined as
F = H - TS
63
The expression for entropy change given by, ΔS = nR ln (V2/V1) + nCv ln (T2/T1) is valid for
simultaneous heating and expansion of an ideal gas.
64
The second law of thermodynamics states that
none of the above.
65
Internal energy of an ideal gas
none of these.
66
A refrigerator works on the principle of __________ law of thermodynamics.
second
67
Pick out the wrong statement.
a. The conversion for a gas phase reaction
increases with decrease in pressure, if there is
an increase in volume accompanying the
reaction.
b. With increase in temperature, the
equilibrium constant increases for an
exothermic reaction.
c. The equilibrium constant of a reaction depends upon temperature only.
d. The conversion for a gas phase reaction
increases with increase in pressure, if there is
a decrease in volume accompanying the
reaction.
With increase in temperature, the equilibrium constant increases for an exothermic reaction.
68
Pick out the wrong statement.
a. Enthalpies of all elements in their standard
states are assumed to be zero.
b. Combustion reactions are never en-dothermic
in nature.
c. Heat of reaction at constant volume is equal to
the change in internal energy.
d. Claussius-clayperon equation is not
applicable to melting process.
Claussius-clayperon equation is not applicable to melting process.
69
Which of the following is affected by the temperature ?
all
70
The molar excess Gibbs free energy, g^E, for a binary liquid mixture at T and P is given by, (g^E/RT) = A . x1. x2, where A is a constant. The corresponding equation for ln y1, where y1 is the activity co-efficient of component 1, is
A . X2^2
71
The adiabatic throttling process of a perfect gas is one of constant enthalpy
which can be performed in a pipe with a constriction.
72
For spontaneous changes in an isolated system (S = entropy)
ds > 0
73
A gas performs the maximum work, when it expands
isobarically
74
There is a change in __________ during the phase transition.
volume
75
Which of the following is Virial equation of state?
PV = A + B/V + C/V^2 + D/V^3 + ...
76
Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is
zero
77
First law of thermodynamics deals with the
direction of energy transfer.
78
Henry's law is closely obeyed by a gas, when its __________ is extremely high.
none of these
79
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 total amount". This is
the distribution law.
80
A solid is transformed into vapour without going to the liquid phase at
triple point
81
A gas mixture of three components is brought in contact with a dispersion of an organic phase in water. The degree of freedom of the system are
3
82
1m^3 of an ideal gas at 500 K 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/mole . K, the final temperature will be
274 K
83
For a thermodynamic system containing 'x' chemical species, the maximum number of phases that can co-exist at equilibrium is
x + 2
84
A reasonably general expression for vapour-liquid phase equilibrium at low to moderate pressure is Φi yi P = Yi xi fi° where, Φ is a vapor fugacity component, Yi is the liquid activity co-efficient and fi° is the fugacity of the pure component i. the Ki value (Yi = Ki xi) is therefore, in general a function of
temperature, pressure and liquid composition xi only.
85
Standard temperature and pressure (S.T.P.) is
0°C and 750 mm Hg
86
Normal temperature and pressure (N.T.P.) corresponds to
20°C and 760 mm Hg.
87
The minimum number of phases that can exist in a system is
1
88
Enthalpy changes over a constant pressure path are always zero for __________ gas.
a perfect
89
The fugacity of a gas in a mixture is equal to the product of its mole fraction and its fugacity in the pure state at the total pressure of the mixture". This is
called Lewis-Randall rule
90
__________ does not change during phase transformation processes like sublimation, melting & vaporisation.
Gibbs free energy
91
Which one is true for a throttling process ?
The inversion temperature is different for different gases.
92
Choose the condition that must be specified in order to liquify CO2 (triple point for CO2 is - 57°C and 5.2 atm).
Pressure and temperature must be kept below 5.2 atm. and - 57°C respectively.
93
One mole of nitrogen at 8 bar and 600 K is contained in a piston-cylinder arrangement. It is brought to 1 bar isothermally against a resisting pressure of 1 bar. The work done (in Joules) by the gas is
10373
94
Lenz's law results from the law of conservation of
energy
95
In the equation, PVn = constant, if the value of n is in between 1 and y (i.e. Cp/Cv), then it represents a reversible __________ process.
polytropic
96
Throttling process is a/an __________ process.
irreversible and constant enthalpy
97
The main feature of Carnot refrigeration cycle is that, it
accomplishes the reverse effect of the heat engine.
98
Charles' law for gases states that
V/2 = Constant
99
If heat contents of CH4, C2H4 and C3H8 are -17.9, 12.5 and -24.8 kcal/mole respectively, than ΔH for the reaction CH4(g) + C2H4(g) C3H8(g) will be __________ Kcal.
-19.4
100
Helmholtz free energy (A) is defined as
A = E - TS
101
As pressure approaches zero, the ratio of fugacity to pressure (f/P) for a gas approaches
unity
102
For any system, what is the minimum number of degrees of freedom?
0
103
At 60° C, vapour pressure of methanol and water are 84.562 kPa and 19.953 kPa respectively. An aqueous solution of methanol at 60° C exerts a pressure of 39.223 kPa; the liquid phase and vapour phase mole fractions of methanol are 0.1686 and 0.5714 respectively. Activity co-efficient of methanol is
1.572
104
The variation of heat of reaction with temperature at constant pressure is given by the __________ law.
Kirchoffs
105
At absolute zero temperature, the __________ of the gas is zero.
volume
106
Which of the following equations is used for the prediction of activity co-efficient from experiments ?
all
107
The equation, , applicable to a binary solution of components. A and B in equilibrium with their vapors at constant temperature and pressure is called the __________ equation.
Gibbs-Duhem-Margules
108
Entropy of a substance remains constant during a/an __________ change.
reversible adiabatic
109
Gases are cooled in Joule-Thomson expansion, when it is __________ inversion temperature.
below
110
PVy = constant, holds good for an isentropic process, which is
reversible and adiabatic.
111
Which of the following behaves most closely like an ideal gas ?
He
112
In the reaction, C + O2 → CO2 ; ΔH = - 94 kcal. What is the heat content (enthalpy)of O2?
zero
113
When a system is in equilibrium for all possible processes, the differential or finite change of entropy is
< 0
114
A system is said to be at equilibrium, if the entropy of the system has reached __________ value.
maximum
115
In the equation, PV^n = constant, if the value of n = ± ∞, then it represents a reversible __________ process.
isometric
116
Degree of freedom of the system ice-water-vapour will be
0
117
A system in which there is exchange of energy but not of mass, is called a/an __________ system.
closed
118
The point at which all the three (solid, liquid and gas) phases co-exist, is known as the __________ point.
triple
119
In an ideal gas mixture, fugacity of a species is equal to its
partial pressure
120
The third law of thermodynamics states that the
heat capacity of a crystalline solid is zero at absolute zero temperature.
121
Consider the reaction, C + O2 ⇌ CO2 ;ΔH = - 94 kcal. What will be the value of ΔH for the reaction CO2 C + O2 ?
+ 94 kcal
122
Which is not a state function ?
Work
123
For an ideal liquid solution, which of the following is unity ?
Activity co-efficient
124
In the decomposition of PCl5 represented by, PCl5 ⇌ PCl3 + Cl2, decrease in the pressure of the system will __________ the degree of dissociation of PCl5.
increase
125
To obtain integrated form of Clausius-Clayperon equation,(1), from the exact Clayperon equafion, it is assumed that the
all
126
In case of an __________ process, the temperature of the system increases.
adiabatic compression
127
Cp of a gas at its critical temperature and pressure
equals 1 kcal/kmol °K.
128
Trouton's ratio is given by (where λb, = molal heat of vaporisation of a substance at its normal boiling point, kcal/kmol Tb = normal boiling point, °K )
λb/Tb
129
Which of the following is true for Virial equation of state ?
Virial co-efficients are function of temperature only.
130
Molar heat capacity of water in equilibrium with ice at constant pressure is __________ Kcal/kg mole . °K
∞
131
A gas can be liquified by pressure alone only, when its temperature is __________ its critical temperature.
less than or equal to
132
For an ideal gas, the internal energy depends upon its __________ only.
temperature
133
Compound having large heat of formation is
more stable.
134
Second law of thermodynamics is concerned with the
direction of energy transfer.
135
Trouton's ratio of __________ liquids is calculated using Kistyakowsky equation.
non-polar
136
The heat capacities for the ideal gas state depend upon the
temperature
137
Refrigeration cycle
involves transfer of heat from low temperature to high temperature.
138
Adiabatic compression of a saturated water vapour makes it
superheated
139
The equation, Cp - Cv = R, is true for __________ gas.
only ideal
140
The internal energy of an incompressible fluid depends upon its
temperature
141
Heat of reaction at constant volume is identified with __________ change.
internal energy
142
The free energy change for a chemical reaction is given by (where, K = equilibrium constant)
-RT lnK
143
Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ____with the increase of reduced temperature.
increases
144
In the reaction, H2 +I2 ⇌ 2HI, addition of an inert gas will
not effect the equilibrium conditions
145
What is the number of degrees of freedom for liquid water in equilibrium with a mixture of nitrogen and water vapor ?
2
146
The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called the __________ temperature.
Boyle
147
If the molar heat capacities (Cp or Cv) of the reactants and products of a chemical reaction are identical, then, with the increase in temperature, the heat of reaction will
remain unaltered
148
All gases above its inversion temperature, in a throttling process will show
a heating effect.
149
First law of thermodynamics is mathematically stated as
dQ = dE + dW
150
Pick out the wrong statement.
a. Surface tension of a substance vanishes at
critical point, as there is no distinction between
liquid and vapour phases at its critical point.
b. Entropy of a system decreases with the
evolution of heat.
c. Change of internal energy is negative for
exothermic reactions.
d. The accentric factor for all materials is
always more than one.
The accentric factor for all materials is always more than one.
151
Translational kinetic energy of molecules of an ideal gas is proportional to (where, T = absolute temperature of the gas )
T
152
Equation which relates pressure, volume and temperature of a gas is called the
equation of state
153
Claussius-Clayperon equation gives accurate result, when the
all of these
154
The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called __________ temperature.
Boyle
155
For a single component two phase mixture, the number of independent variable properties are
one
156
__________ law of thermodynamics ascertains the direction of a particular spontaneous process.
Second
157
At normal boiling point, molar entropy of vaporisation is __________ Joule/K°.mole.
92
158
For an ideal solution, the value of activity co-efficient is
1
159
The expression, nCv(T2 - T1), is for the __________ of an ideal gas.
work done under adiabatic condition
160
Which of the following is a widely used refrigerant in vapour compression refrigeration system (using large centrifugal compressor)?
Freon
161
Internal energy is equal to the heat absorbed in case of a/an __________ process.
constant volume
162
The first law of thermodynamics is a restatement of the law of conservation of
mass
163
Joule-Thomson co-efficient for a perfect gas is
positive
164
In an adiabatic process, the
heat transfer is zero.
165
A nozzle is a device, which
increases kinetic energy and decreases pressure.
166
Duringthe phase transition, __________ changes.
volume
167
The work done in an adiabatic change in a particular gas depends upon changes in the __________ only.
temperature
168
In an isothermal process on an ideal gas, the pressure increases by 0.5 percent. The volume decreases by about __________ percent.
0.5
169
Which of the following is not a unit of the equilibrium constant Kp? (where, Δx = number of moles of products number of moles of reactants)
(atm)Δx2, when Δx > 0
170
Pick out the correct statement.
a. The available energy in an isolated system for
all irreversible (real) processes decreases.
b. The efficiency of a Carnot engine increases, if
the sink temperature is decreased.
c. The reversible work for compression in nonflow process under isothermal condition is the
change in Helmholtz free energy.
d. all (a), (b) and (c)
all
171
Partial molal quantities are important in the study of
non-ideal mixtures
172
Number of degrees of freedom for a three phase system in equilibrium comprising of three non-reacting chemical species is
2
173
Critical solution temperature (or the con-solute temperature) for partially miscible liquids (e.g., phenol-water) is the minimum temperature at which
a homogeneous solution (say of phenol water) is formed.
174
Enthalpy 'H' is defined as
H - E = PV
175
One ton of refrigeration is defined as the heat rate corresponding to melting of one ton of ice in one
day
176
__________ functions are exemplified by heat and work.
Path
177
In an irreversible process
Tds - dE + dW< 0
178
What is the number of degree of freedom for a system of two miscible non-reacting species in vapor-liquid equilibrium forming an azeotrope ?
1
179
The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is
R loge 4
180
PVγ = Constant (where, γ = Cp/Cv) is valid for a/an __________ process.
adiabatic
181
Claude gas liquefaction process employs cooling
by expansion in an engine.
182
Which of the following will increase the volume of a real gas by four times ?
Reducing pressure to one fourth at constant temperature.
183
Pick out the wrong statement.
a. A refriferation cycle violates the second
law of thermadynamics.
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.
A refriferation cycle violates the second law of thermadynamics.
184
The equation, PV = nRT, is best obeyed by gases at
low pressure & high temperature.
185
Internal energy of an element at 1 atm and 25° C is __________ kcal/kg.mole.
0
186
Which of the following liquid metals has the highest thermal conductivity ?
Molten sodium
187
Which of the following has the least thermal efficiency ?
Steam engine
188
Joule-Thomson Co-efficient at any point on the inversion curve is
0
189
Pick out the wrong statement.
a. The values of are zero for a real gas at its critical point.
b. Heat transferred is equal to the change in the
enthalpy of the system, for a constant
pressure, non-flow, mechanically reversible
process.
c. Thermal efficiency of a Carnot engine
depends upon the properties of the
working fluid besides the source & sink
temperatures.
d. During a reversible adiabatic process, the
entropy of a substance remains constant.
Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures.
190
Number of components (C), phase (P) and degrees of freedom (F) are related by Gibbs phase rule as
P + F - C = 2
191
The value of Cp & Cv respectively for monoatomic gases in Kcal/kg Mole . °K are
5 & 3
192
(1) is the mathematical expression for
Joule-Thompson co-efficient.
193
In case of a close thermodynamic system, there is __________ across the boundaries.
no mass transfer but heat transfer
194
During a reversible isothermal expansion of an ideal gas, the entropy change is
+ve
195
As the temperature is lowered towards the absolute zero, the value of (1), then approaches
zero
196
Which of the following is not affected by temperature changes ?
None of these
197
For an ideal gas, the activity co-efficient is
unity at all pressures.
198
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
199
Generation of heat by friction is an example of a/an __________ change.
irreversible
200
A domestic refrigerator has a/an __________ cooled condenser.
air
201
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
202
If we increase the pressure on a substance (which is at its triple point), then the triple point
remains unchanged
203
In an ideal refrigeration cycle, the change in internal energy of the fluid is
0
204
Free energy
all
205
"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
206
Fugacity is a measure of the
escaping tendencies of the same substance in different phases of a system.
207
The quantitative effect of temperature on chemical equilibrium is given by the
Vant-Hoff equation.
208
For an irreversible process involving only pressure-volume work
(dF)T, p <0
209
Ideal refrigeration cycle is
same as reverse Carnot cycle.
210
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
320, 000 kW
211
The enthalpy change when ammonia gas is dissolved in water is called the heat of
solution
212
The value of Joule-Thomson co-efficient, in case where cooling occurs after the throttling process is
+ve
213
The specific heat of saturated water vapour at 100°C is
-ve
214
For a multicomponent system, the term chemical potential is equivalent to the
partial molar free energy.
215
The change in Gibbs freee energy for vaporisation of a pure substance is
zero
216
Critical compressibility factor for all substances
are more or less constant (vary from 0.2 to 0.3).
217
What is the degree of freedom for two mis-cible (non-reacting) substances in vapor-liquid equilibrium forming an azeotrope ?
2
218
For a given substance at a specified temperature, activity is __________ to fugacity.
directly proportional
219
In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in
enhanced COP.
220
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
6753.5
221
As the temperature is lowered towards the absolute zero, the value of the quantity approaches
zero
222
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 decreases.
223
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
224
The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is
less
225
The unit of fugacity is the same as that of the
pressure
226
Filling of gas from a high pressure cylinder into small bottles is an example of a/an __________ process.
unsteady
227
A large iceberg melts at the base, but not at the top, because of the reason that
due to the high pressure at the base, its melting point reduces.
228
At the critical point of a substance
all
229
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)
Δ S1 is always > Δ SR
230
What is the value of Joule-Thomson co-efficient for an ideal gas ?
0
231
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)
geometric
232
y = specific heat ratio of an ideal gas is equal to
all
233
Consider the process A & B shown in the figure given below (1) In this case, it is possilbe that
process A is isothermal while B is adiabatic.
234
Gibbs free energy of a pure fluid approaches __________ as the pressure tends to zero at constant temperature.
minus infinity
235
As the entropy of the universe is increasing, day by day, the work producing capacity of a heat engine is
decreasing
236
An irreversible process
yields an amount of work less than that of a reversible process.
237
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.
isothermal
238
Free energy change of mixing two liquid substances is a function of the
all
239
Pick out the wrong statement.
a. System (of partially miscible liquid pairs), in
which the mutual solubility increases with rise
in temperature, are said to possess an upper
consolute temperature.
b. Systems, in which the mutual solubility
increases with decrease in temperature, are
said to possess lower consolute temperature.
c. 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.
d. none of these
none of these
240
The total change in the enthalpy of a system is independent of the
number of intermediate chemical reactions involved.
241
Number of phases in a colloidal system are
2
242
Free energy changes for two reaction mechanism 'X' and 'Y are respectively - 15 and - 5 units. It implies that X is
faster than Y
243
Vapour which is at a pressure smaller than the saturation pressure for the temperature involved is called a __________ vapour.
superheated
244
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
245
The kinetic energy of gas molecule is zero at
-273°C
246
Which of the following is not an intensive property ?
Volume
247
The necessary and sufficient condition for equilibrium between two phases is
the chemical potential of each component should be same in the two phases.
248
Specific volume of an ideal gas is
the reciprocal of its density.
249
Pick out the extensive property out of the following.
Free energy
250
Entropy change of the reaction, H2O(liquid) H2O(gas), is termed as the enthalpy of
vaporisation
251
Which law of the thermodynamics provids basis for measuring the thermodynamic property ?
Zeroth law
252
Gibbs free energy per mole for a pure substance is equal to the
chemical potential
253
Gibbs free energy at constant pressure and temperature under equilibrium conditions is
minimum
254
With increase in pressure (above atmospheric pressure), the Cp of a gas
increases
255
A change in state involving a decrease in entropy can be spontaneous, only if
it is exothermic.
256
Joule-Thomson co-efficient which is defined as, (1) , changes sign at a temperature known as inversion temperature. The value of Joule-Thomson co-efficient at inversion temperature is
0
257
__________ calorimeter is normally used for measuring the dryness fraction of steam, when it is very low.
A combination of separating & throttling
258
The amount of heat required to decompose a compound into its elements is __________ the heat of formation of that compound from its elements.
same as
259
For a constant volume process
dE = CvdT
260
In case of the decomposition of hydroiodic acid (2HI ⇌ H2 + I2), addition of H2 (at equilibrium condition) will
diminish the degree of dissociation of HI.
261
In any spontaneous process, the __________ free energy decreases.
Helmholtz, Gibbs
262
The equation DU = Tds - PdV is applicable to infinitesimal changes occuring in
a closed system with changes in composition.
263
Heat is added at constant temperature in an ideal __________ cycle.
Stirling
264
Pick out the correct equation relating 'F' and 'A'.
F = A + PV
265
In a reversible process
Tds = dE + dW
266
Cv for an ideal gas
is independent of both pressure and volume.
267
In a homogeneous solution, the activity co-efficient of a component depends upon the
all
268
Pick out the wrong statement:
a. The expansion of a gas in vacuum is an
irreversible process.
b. An isometric process is a constant
pressure process.
c. Entropy change for a reversible adiabatic
process is zero.
d. Free energy change for a spontaneous
process is negative
An isometric process is a constant pressure process.
269
With increase in compression ratio, the efficiency of the otto engine
increases
270
The chemical potential of any constituent of an ideal solution depends on the __________ of the solution.
all
271
Fugacity and pressure are numerically equal, when the gas is
in ideal state
272
Refrigerants commonly used for domestic refrigerators are
ethyl chloride or methyle chloride
273
Absolute zero temperature signifies the
temperature of the heat reservoir to which a Carnot engine rejects no heat.
274
Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.).
Gibbs free energy
275
Heat of formation of an element in its standard state is
0
276
The equation relating E, P, V and T which is true for all substanes under all conditions is given by (1) .This equation is called the
thermodynamic equation of state.
277
For an exothremic reaction
both ΔH and ΔE are negative.
278
Pick out the wrong statement.
a. An ideal liquid or solid solution is defined as
one in which each component obeys Raoult’s
law.
b. 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.
c. Henry’s law is rigorously correct in the limit of
infinite dilution.
d. none of these.
none of these.
279
The shape of T-S diagram for Carnot Cycle is a
rectangle
280
For an isothermal process, the internal energy of a gas
remains unchanged
281
In the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process.
isothermal
282
For the gaseous phase chemical reaction, C2H4(g) + H2O(g) ⇌ C2H5OH(g), the equilibrium conversion does not depend on the
none of these.
283
The first law of thermodynamics is a statement of conservation of
energy
284
"Dry ice" is
solid carbon dioxide
285
Which of the following non-flow reversible compression processes require maximum work ?
Adiabatic process
286
Pick out the correct statement.
a. A real gas on expansion in vacuum gets
heated up.
b. An ideal gas on expansion in vacuum gets
cooled.
c. An ideal gas on expansion in vacuum gets
heated up.
d. 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.
287
"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.
288
Sound waves propagation in air exemplifies an __________ process.
adiabatic
289
For equilibrium process (i.e. reversible) in an isolated system
ds = 0
290
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 and P
291
With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure
increases
292
For an ideal gas, the enthalpy
is independent of pressure.
293
Efficiency of a heat engine working on Carnot cycle between two temperature levels depends upon the
two temperatures only.
294
In Joule-Thomson porous plug experiment, the
enthalpy does not remain constant.
295
A Carnot cycle consists of the following steps :
Two isothermals and two isentropics.
296
For a cyclic process, a fixed ratio between heat and work
always exists
297
Which of the following is not a common refrigerant ?
Ethylene
298
The most important application of distribution law is in
liquid extraction
299
Pick out the correct statement.
a. Entropy and enthalpy are path functions.
b. In a closed system, the energy can be
exchanged with the surrounding, while. matter
can not be exchanged.
c. All the natural processes are reversible in
nature.
d. Work is a state function.
All the natural processes are reversible in nature.
300
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
301
Gibbs free energy of mixing at constant pressure and temperature is always
- ve
302
The compressibility factor for an ideal gas is 1. Its value for any other real gas is
either <1 or >1, depends on the nature of the gas
303
If two gases have same reduced temperature and reduced pressure, then they will have the same
none of these
304
Which of the following is an extensive property of a system ?
Heat capacity
305
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
306
Cp - Cv = R is valid for __________ gases.
ideal
307
At a given temperature, the volume of a gas dissolved in a solvent __________ with increase in pressure.
remains unchanged
308
Which is an example of closed system ?
Lquid cooling system of an automobile
309
Melting of wax is accompanied with __________ in entropy.
increase
310
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
ACBDA
311
Work done in case of free expansion is
zero
312
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
1
313
During adiabatic expansion of gas
none of these.
314
Which of the following has the minimum value of COP for a given refrigeration effect?
Air refrigeration cycle.
315
__________ decreases during adiabatic throttling of a perfect gas.
Pressure
316
Pick out the wrong statement.
a. Minimum number of degree of freedom of a
system is zero.
b. Degree of freedom of a system containing a
gaseous mixture of helium, carbon dioxide and
hydrogen is 4.
c. For a two phase system in equilibrium made
up of four non-reacting chemical species, the
number of degrees of freedom is 4.
d. 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.
317
Tea kept in a thermos flask is vigorously shaken. If the tea is considered as a system, then its temperature will
increase
318
Change of heat content when one mole of compound is burnt in oxygen at constant pressure is called the
heat of combustion
319
Clausius - Clayperon equation is applicable to __________ equilibrium processes.
All
320
In which of the following reaction equilibria, the value of equilibrium constant Kp will be more than is Kc ?
N2O4 ⇌ 2NO2
321
After throttling, gas temperature
decreases
322
The chemical potential for a pure substance is __________ its partial molal free energy.
equal to
323
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.
324
COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about
3.5
325
The number of degrees of freedom for a mixture of ice and water (liquid) are
1
326
On opening the door of an operating refrigerator kept in a closed room, the temperature of the room will
increase
327
Domestic refrigerator usually works on the __________ refrigeration cycle.
absorption
328
Gibbs-Duhem equation
states that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure.
329
Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is
2
330
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
temperature
331
"When a gas is expanded from high pressure region to low pressure region ; temper -ature change occurs". This phenomenon is related to the
Joule-Thomson effect
332
The internal energy of an ideal gas does not change in a reversible __________ process.
isothermal
333
A/an __________ system is exemplified by a vessel containing a volatile liquid in contact with its vapor.
open
334
In a P-V diagram (for an ideal gas), an isothermal curve will coincide withan adiabatic curve (through a point), when
Cp = Cv
335
For an ideal gas, the chemical potential is given by
RT dlnP
336
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
337
In the ammonia synthesis reaction, N2 + 3H2 ⇌ 2NH3 + 22.4 kcal, the formation of NH3 will be favoured by
both low temperature and high pressure.
338
Entropy change for an irreversible isolated system is
> 0
339
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
340
The unit of equilibrium constant of a chemical reaction is the same as that of
none of these
341
Which of the following equations is obtained on combining 1st and 2nd law of thermodynamics, for a system of constant mass?
dE = Tds - PdV
342
The Joule-Thomson co-efficient is defined as (∂T/∂P)H. Its value at the inversion point is
0
343
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.
increases
344
Entropy is a/an
none of these
345
At triple point (for one component system), vapour pressure of solid as compared to that of liquid will be
same
346
4 kg moles of an ideal gas expands in vacuum spontaneously. The work done is
0
347
Which of the following is not correct for a reversible adiabatic process ?
none of these
348
The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2 (when, T1 > T2) is given by (T1 - T2)/T1. The co-efficient of performance (C.O.P.) of a Carnot heat pump operating between T1 and T2 is given by
T1/(T1-T2)
349
Throttling (Joule-Thomson effect) process is a constant __________ process.
enthalpy
350
Boiling of liquid is accompanied with increase in the
vapor pressure.
351
Change of state namely evaportation condensation, freezing and melting is an __________ process.
isothermal
352
Which of the following is not an equation of state?
Clausius Clayperon equation
353
A gas shows deviation from ideal behaviour at
low temperature and high pressure.
354
The difference between isothermal compressibility and adiabatic compressibility for an ideal gas is
+ve
355
The expression for entropy change given by, ΔS = - nR ln (P2/P1), holds good for
reversible isothermal volume change.
356
With increase in temperature, the internal energy of a substance
increases
357
The temperature at which both liquid and gas phases are identical, is called the __________ point.
critical
358
What is the value of ln y (where y = activity co-efficient) for ideal gases ?
Zero
359
A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system
U and S both decreases
360
Which is not a refrigerant ?
C2H4Cl2
361
The partial pressure of each constituent present in an alloy is __________ the total vapor pressure exerted by the alloy.
less than
362
The four properties of a system viz. P, V, T, S are related by __________ equation.
Maxwell's
363
If the pressure on 100 c.c. of air is halved, then its volume (at the same temperature) would be __________ c.c.
200
364
Pick out the wrong statement.
a. Cp of monoatomic gases such as metallic
vapor is about 5 kcal/kg.atom.
b. The heat capacity of solid inorganic
substance is exactly equal to the heat
capacity of the substance in the molten
state.
c. There is an increase in entropy, when a
spontaneous change occurs in an isolated
system.
d. At absolute zero temperature, the heat
capacity for many pure crystalline substances
is zero.
The heat capacity of solid inorganic substance is exactly equal to the heat capacity of the substance in the molten state.
365
The number of degrees of freedom for an azeotropic mixture in a two component vapour-liquid equilibria is/are
one
366
Any substance above its critical temperature exists as
gas
367
Which of the following decreases with increase in pressure ?
Melting point of ice
368
Isentropic process means a constant __________ process.
entropy .
369
(1) is the mathematical expression
co-efficient of thermal expansion.
370
In case of steady flow compression polytropic process (PVn = constant), the work done on air is the lowest, when
n = 1
371
A liquid under pressure greater than its vapour pressure for the temperature involved is called a __________ liquid.
subcooled
372
For a real gas, the chemical potential is given by
RT dlnf
373
At absolute zero temperature, all substances have the same
heat capacity
374
Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in
increased COP.
375
Pick out the correct statement.
a. If an insoluble gas is passed through a volatile
liquid placed in a perfectly insulated container,
the temperature of the liquid will increase.
b. A process is irreversible as long as Δ S for the
system is greater than zero.
c. The mechanical work done by a system is
always equal to P.dV.
d. The heat of formation of a compound is
defined as the heat of reaction leading to
the formation of the compound from its
reactants.
The heat of formation of a compound is defined as the heat of reaction leading to the formation of the compound from its reactants.
376
Grams of butane (C4H10) formed by the liquefaction of 448 litres of the gas (measured at (STP) would be
1160
377
The thermodynamic law, PVy = constant, is not applicable in case of
free expansion of an ideal gas.
378
Mollier diagram is a plot of
entropy vs. enthalpy
379
is the mathematical expression for
none of these
380
The activity of an ideal gas is numerically __________ its pressure.
equal to
381
Specific heat of a gas for a reversible adiabatic process is
zero
382
When a gas in a vessel expands, its internal energy decreases. The process involved is
reversible
383
A system is said to be isopiestic, if there is no __________ change.
pressure
384
In a turbine, the fluid expands almost
adiabatically
385
The unity of Planck's constant 'h' in the equation, E = hv is
J.S
386
Specific/molar Gibbs free energy for a pure substance does not change during
either
387
Refrigeration capacity of a household refrigerator may be round about __________ tons.
0.15
388
(1) is the mathematical expression for
none of these
389
An ideal gas is taken around the cycle ABCA as shown in P-V diagram below :The work done by the gas during the cycle is equal to
3 P1V1
390
In polytropic process (PVn = constant), if n = 1; it means a/an __________ process.
isothermal
391
The melting point of paraffin wax (which contracts on solidification) __________ with pressure rise.
increases
392
Co-efficient of Performance (COP) of a refrigerator is the ratio of the
refrigeration obtained to the work required.
393
A solid metallic block weighing 5 kg has an initial temperature of 500°C. 40 kg of water initially at 25°C is contained in a perfectly insulated tank. The metallic block is brought into contact with water. Both of them come to equilibrium. Specific heat of block material is 0.4 kJ.kg^-1. K^-1. Ignoring the effect of expansion and contraction and also the heat capacity to tank, the total entropy change in kJ.kg^-1 , K^-1 is
0
394
dW and dq are not the exact differential, because q and W are
path functions
395
Activity co-efficient is a measure of the
departure from ideal solution behaviour.
396
While dissolving a gas into a liquid at a constant temperature, the ratio of the concentration of the gas in the solution phase and in the gaseous phase is
constant
397
Which of the following units is not present in both the vapor compression refrigeration system and absorption refrigeration system ?
Compressor
398
For an isothermal reversible compression of an ideal gas
ΔE = ΔH = 0
399
Melting of ice exemplifies a/an
endothermic reaction.
400
A refrigeration cycle is the same as a __________ cycle,
reversed heat engine
401
At __________ point, all the three phases (i.e.solid, liquid and gas) co-exist.
triple
402
Kopp's rule is used to calculate the heat capacity of
solids
403
__________ explains the equilibrium constant for any chemical reaction.
Law of mass action
404
Which of the following is not a reversible process ?
Solution of NaCl in water at 50°C.
405
Pick out the wrong statement.
a. A closed system does not permit exchange of
mass with its surroundings but may permit
exchange of energy.
b. An open system permits exchange of both
mass and energy with its surroundings.
c. The term microstate is used to characterise an
individual, whereas macro-state is used to
designate a group of micro-states with
common characteristics.
d. none of the above.
none of the above.
406
Which of the following exemplifies an adiabatic process ?
Sudden bursting of a cycle tube.
407
Entropy, which is a measure of the disorder of a system is
zero at absolute zero temperature for a perfect crystalline substance.
408
Critical temperature is defined as the temperature above which a gas will
never liquify however high the pressure may be.
409
The standard Gibbs free energy change of a reaction depends on the equilibrium
temperature
410
Gibbs-Duhem equation relates composition in liquid phase and the __________ at constant temperature & pressure.
all
411
In an ideal solution, the activity of a component equals its
mole fraction.
412
A gas has a volume of 27.3 c.c. at 0°C. Its volume at 10°C (if pressure remains unchanged) will be __________ c.c.
28.3
413
Clayperon equation deals with the
rate of change of vapour pressure with temperature.
414
Which of the following is an undesirable characteristics of a refrigerant ?
It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils.
415
"The rate at which a substance reacts is proportional to its active mass and the rate of a chemical reaction is proportional to the product of active masses of the reacting substances". This is the
none of these.
416
What is the ratio of adiabatic compressibility to isothermal compressibility ?
< 1
417
The absolute entropy for all crystalline substances at absolute zero temperature is
zero
418
Pick out the wrong statement.
a. Phase rule variables are intensive properties.
b. Heat and work are both state function.
c. The work done by expansion of a gas in
vacuum is zero.
d. CP and CV are state function.
Heat and work are both state function.
419
Compressibility factor of a gas is
unity, if it follows PV = nRT.
420
Which of the following is not an extensive property ?
Refractive index
421
Forward reaction will be favoured for the exothermic reaction, represented by CO + H2O ⇌ CO2 + H2, by
low temperature and high pressure.
422
Enthalpy of a gas depends upon its
temperature
423
When dilute aqueous solutions of two salts are mixed, the process is associated with
increase in temperature.
424
Pick out the correct statement.
a. Like internal energy and enthalphy, the
absolute value of standard entropy for
elementary substances is zero.
b. Melting of ice involves increase in enthalpy
and a decrease in randomness.
c. The internal energy of an ideal gas depends
only on its pressure.
d. Maximum work is done under reversible
conditions.
Maximum work is done under reversible conditions.
425
Chemical engineering thermodynamics is concerned with the __________ in/of chemical processes.
energy transformation from one form to the another
426
An isolated system can exchange __________ with its surroundings.
neither matter nor energy
427
Requisites of a reversible process is that the
friction in the system should be absent.
428
Fugacity is most helpful in
representing actual behaviour of real gases.
429
The energy of activation of exothermic reaction is
not possible to predict.
430
Pick out the wrong statement.
a. The chemical potential of a pure substance
depends upon the temperature and pressure.
b. The chemical potential of a component in a
system is directly proportional to the escaping
tendency of that component.
c. The chemical potential of ith species (μi) in
an ideal gas mixture approaches zero as
the pressure or mole fraction (xi) tends to
be zero at constant temperature.
d. The chemical potential of species 'i' in the
mixture (μi) is mathematically represented
as where, n, ni and nj respectively denote the total
number of moles, moles of ith species and all
mole numbers except ith species. 'G' is Gibbs
molar free energy.
The chemical potential of ith species (μi) in an ideal gas mixture approaches zero as the pressure or mole fraction (xi) tends to be zero at constant temperature.
431
In the reaction; N2 + O2 (1) 2NO, increasing the pressure will result in
no change in equilibrium condition.
432
A cyclic engine exchanges heat with two reservoirs maintained at 100 and 300°C respectively. The maximum work (in J) that can be obtained from 1000 J of heat extracted from the hot reservoir is
349
433
Pick out the wrong statement.
a. Trouton's ratio of non-polar liquids is
calculated using Kistyakowasky equation.
b. Thermal efficiency of a Carnot engine is
always less than 1.
c. An equation relating pressure, volume and
temperature of a gas is called ideal gas
equation.
d. none of these.
An equation relating pressure, volume and temperature of a gas is called ideal gas equation.
434
When a gas is subjected to adiabatic expansion, it gets cooled due to
energy spent in doing work.
435
Joule-Thomson effect i.e., a throttling process is a constant __________ process.
enthalpy
436
In the equation, PV^n = Constant, if the value of n = 0, then it represents a reversible __________ process.
isobaric
437
Work done in an adiabatic process between two states depends on the
end states only
438
The number of degree of freedom for an azeotropic mixture of ethanol and water in vapour-liquid equilibrium, is
1
439
The internal energy of an ideal gas is a function of its __________ only.
temperature
440
At constant temperature and pressure, for one mole of a pure substance, the ratio of the free energy to the chemical potential is
one
441
The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition.
Gibbs free energy
442
Work done is a
path function
443
Extensive properties of a thermodynamic system depend upon the __________ of the system.
mass
444
Near their critical temperatures, all gases occupy volumes __________ that of the ideal gas.
less than
445
Maximum work that could be secured by expanding the gas over a given pressure range is the __________ work.
isothermal
446
Internal energy change of a system over one complete cycle in a cyclic process is
zero
447
Heating of water under atmospheric pressure is an __________ process.
isobaric
448
Van Laar equation deals with the activity co-efficients in
binary solutions
449
High __________ is an undesirable property for a good refrigerant.
viscosity
450
Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the
low pressure and low temperature.
451
Entropy is a measure of the __________ of a system.
disorder
452
A chemical reaction will occur spontaneously at constant pressure and temperature, if the free energy is
negative
453
Fundamental principle of refrigeration is based on the __________ law of thermodynamics.
second
454
For a spontaneous process, free energy
decreases whereas the entropy increases
455
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 ?
Carnot refrigeration cycle.
456
In a working refrigerator, the value of COP is always
> 1
457
A refrigerator may be termed as a
heat pump
458
For a stable phase at constant pressure and temperature, the fugacity of each component in a binary system __________ as its mole fraction increases.
increases
459
Which of the following is not an intensive property ?
Heat capacity
460
Out of the following refrigration cycles, which one has the minimum COP (Co-efficient of performance)?
Air cycle
461
Measurement of thermodynamic property of temperature is facilitated by __________ law of thermodynamics.
zeroth
462
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
-RT ln 0.5
463
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.
327
464
Isobaric process means a constant process.
pressure
465
No work is done by the system, when a reaction occurs at constant
volume
466
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
Clayperon-Claussius equation
467
The freezing point of a liquid decreases when the pressure is increased, if the liquid __________ while freezing.
contracts
468
"At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero". This follows from the
third law of thermodynamics
469
During Joule-Thomson expansion of gases
enthalpy remains constant.
470
The accentric factor of a materical, 'ω', is defined as ω = -log10(Pr^sat)Tr^-1 = 0.7, where, Pr^sat = reduced vapor pressure, Tr = reduced temperature. The value of accentric factor is always
< 1
471
Degress of freedom at triple point will be
0
472
"Law of corresponding states" says that
, two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same.
473
Linde gas liquefaction process employs cooling
by throttling
474
Pick out the wrong statement pertaining to the decomposition of PCl5 represented by, PCl5 ⇌ PCl3 + Cl2.Degree of dissociation of PCl5 will
none of these
475
Boyle's law for gases states that
(1) , when temperature & mass of the gas remain constant.
476
1st law of thermodynamics is nothing but the law of conservation of
energy
477
In a reversible chemical reaction (where, Δx = number of moles of products-number of moles of reactants )
all
478
Out of the following refrigeration cycles, which one has maximum COP ?
Carnot cycle
479
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.
Under reversible conditions, the adiabatic work is less than isothermal work.
480
In any spontaneous process,
both F and A decreases
481
Which of the following is a thermodynamic property of a system ?
Entropy
482
Equilibrium constant decreases as the temperature
increases, for an exothermic reaction.
483
The expression, (1) , gives the free energy change
with pressure changes at constant temperature.
484
All gases during throttling process at atmospheric temperature and pressure show a cooling effect except
H2
485
Compressibility factor for almost all the gases are approximately same at the same
reduced pressure and reduced temperature.
486
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.
The fugacity co-efficient is zero for an ideal gas.
487
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.
none of these
488
The chemical potential of a component (μi) of a phase is the amount by which its capacity for doing all work, barring work of expansion is increased per unit amount of sustance added for an infinitesimal addition at constant temperature and pressure. It is given by
all
489
In jet refrigerators, the refrigerating fluid is practically always
water
490
Water on heating from 1 to 4°C
contracts
491
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.
Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio.
492
When pressure is applied on the system, ice<---->water, then
more water will be formed.
493
Partial molar free energy of an element A in solution is same as its
chemical potential
494
Free energy change at equilibrium is
zero
