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