Thermodynamics Flashcards
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. Chemical potential
b. Surface tension
c. Heat capacity
d. None of these
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
"Law of corresponding states" says that
, two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same.
28
Linde gas liquefaction process employs cooling
by throttling
29
Pick out the wrong statement pertaining to the decomposition of PCl5 represented by, PCl5 ⇌ PCl3 + Cl2.Degree of dissociation of PCl5 will
a. decrease on addition of Cl2.
b. increase on addition of an inert gas at constant pressure.
c. decrease on increasing the pressure of the system.
d. none of these
none of these
30
Degress of freedom at triple point will be
0
31
1st law of thermodynamics is nothing but the law of conservation of
energy
32
In a reversible chemical reaction (where, Δx = number of moles of products-number of moles of reactants )
a. addition of inert gas favours the forward reaction, when Δx is positive.
b. pressure has no effect on equilibrium, when Δn = 0.
c. addition of inert gas has no effect on the equilibrium constant at constant volume for any value of Δx (+ ve, - ve) or zero).
d. all 'a', 'b' & 'c'.
all of these
33
Out of the following refrigeration cycles, which one has maximum COP ?
Carnot cycle
34
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.
35
In any spontaneous process,
both F and A decreases
36
Which of the following is a thermodynamic property of a system ?
a. Concentration
b. Mass
c. Temperature
d. Entropy
Entropy
37
Equilibrium constant decreases as the temperature
increases, for an exothermic reaction.
38
All gases during throttling process at atmospheric temperature and pressure show a cooling effect except
H2
39
Compressibility factor for almost all the gases are approximately same at the same
reduced pressure and reduced temperature.
40
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.
41
The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.
a. kinematic viscosity
b. work
c. temperature
d. none of these
none of these
42
In jet refrigerators, the refrigerating fluid is practically always
water
43
Water on heating from 1 to 4°C
contracts
44
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.
45
When pressure is applied on the system, ice<---->water, then
more water will be formed.
46
Partial molar free energy of an element A in solution is same as its
chemical potential
47
Free energy change at equilibrium is
zero
48
The temperature at which both liquid and gas phases are identical, is called the __________ point.
critical
49
What is the value of ln y (where y = activity co-efficient) for ideal gases ?
Zero
50
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
51
Which is not a refrigerant ?
a. SO2
b. NH3
c. CCl2F2
d. C2H4Cl2
C2H4Cl2
52
The partial pressure of each constituent present in an alloy is __________ the total vapor pressure exerted by the alloy.
less than
53
The four properties of a system viz. P, V, T, S are related by __________ equation.
Maxwell's
54
If the pressure on 100 c.c. of air is halved, then its volume (at the same temperature) would be __________ c.c.
200
55
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.
56
The number of degrees of freedom for an azeotropic mixture in a two component vapour-liquid equilibria is/are
one
57
Any substance above its critical temperature exists as
gas
58
Which of the following decreases with increase in pressure ?
a. Melting point of ice
b. Melting point of wax
c. Boiling point of liquids
d. none of these
Melting point of ice
59
Isentropic process means a constant __________ process.
entropy .
60
The number of degrees of freedom for an azeotropic mixture in a two component vapour-liquid equilibria is/are
one
61
In case of steady flow compression polytropic process (PVn = constant), the work done on air is the lowest, when
n = 1
62
A liquid under pressure greater than its vapour pressure for the temperature involved is called a __________ liquid.
subcooled
63
For a real gas, the chemical potential is given by
RT dlnf
64
At absolute zero temperature, all substances have the same
heat capacity
65
Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in
increased COP.
66
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.
67
Grams of butane (C4H10) formed by the liquefaction of 448 litres of the gas (measured at (STP) would be
1160
68
The thermodynamic law, PVy = constant, is not applicable in case of
free expansion of an ideal gas.
69
Mollier diagram is a plot of
entropy vs. enthalpy
70
The activity of an ideal gas is numerically __________ its pressure.
equal to
71
Specific heat of a gas for a reversible adiabatic process is
zero
72
When a gas in a vessel expands, its internal energy decreases. The process involved is
reversible
73
A system is said to be isopiestic, if there is no __________ change.
pressure
74
In a turbine, the fluid expands almost
adiabatically
75
The unity of Planck's constant 'h' in the equation, E = hv is
J.S
76
Specific/molar Gibbs free energy for a pure substance does not change during
a. sublimation
b. vaporisation
c. melting
d. either (a), (b) or (c)
either (a), (b) or (c)
77
Refrigeration capacity of a household refrigerator may be round about __________ tons.
0.15
78
In polytropic process (PVn = constant), if n = 1; it means a/an __________ process.
isothermal
79
The melting point of paraffin wax (which contracts on solidification) __________ with pressure rise.
increases
80
Co-efficient of Performance (COP) of a refrigerator is the ratio of the
refrigeration obtained to the work required.
81
dW and dq are not the exact differential, because q and W are
path functions
82
Activity co-efficient is a measure of the
departure from ideal solution behaviour.
83
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
84
Which of the following units is not present in both the vapor compression refrigeration system and absorption refrigeration system ?
a. Expansion valve
b. Condenser
c. Refrigerator
d. Compressor
Compressor
85
For an isothermal reversible compression of an ideal gas
ΔE = ΔH = 0
86
Melting of ice exemplifies a/an
endothermic reaction.
87
A refrigeration cycle is the same as a __________ cycle,
reversed heat engine
88
At __________ point, all the three phases (i.e.solid, liquid and gas) co-exist.
triple
89
Kopp's rule is used to calculate the heat capacity of
solids
90
__________ explains the equilibrium constant for any chemical reaction.
Law of mass action
91
Which of the following is not a reversible process ?
a. Expansion of an ideal gas against constant pressure.
b. Atmospheric pressure vaporisation of water at 100°C.
c. Solution of NaCl in water at 50°C.
d. None of these.
Solution of NaCl in water at 50°C.
92
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.
93
Which of the following exemplifies an adiabatic process ?
a. Melting of ice.
b. Condensation of alcohol vapor.
c. Sudden bursting of a cycle tube.
d. Evaporation of water.
Sudden bursting of a cycle tube.
94
Entropy, which is a measure of the disorder of a system is
zero at absolute zero temperature for a perfect crystalline substance.
95
Critical temperature is defined as the temperature above which a gas will
never liquify however high the pressure may be.
96
The standard Gibbs free energy change of a reaction depends on the equilibrium
temperature
97
Gibbs-Duhem equation relates composition in liquid phase and the __________ at constant temperature & pressure.
a. fugacity
b. partial pressure
c. activity co-efficient
d. (a), (b), and (c)
(a), (b), and (c)
98
In an ideal solution, the activity of a component equals its
mole fraction.
99
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
100
Clayperon equation deals with the
rate of change of vapour pressure with temperature.
101
Which of the following is an undesirable characteristics of a refrigerant ?
a. It should be non-explosive.
b. It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils.
c. Its vapor pressure at the condenser temperature should be very high.
d. None of these.
It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils.
102
"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
a. Lewis-Randall rule.
b. statement of Vant-Hoff equation.
c. Le-Chatelier's principle.
d. none of these.
none of these.
103
What is the ratio of adiabatic compressibility to isothermal compressibility ?
< 1
104
The absolute entropy for all crystalline substances at absolute zero temperature is
zero
105
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.
106
Compressibility factor of a gas is
unity, if it follows PV = nRT.
107
Which of the following is not an extensive property ?
a. Free energy
b. Entropy
c. Refractive index
d. None of these
Refractive index
108
Forward reaction will be favoured for the exothermic reaction, represented by CO + H2O ⇌ CO2 + H2, by
low temperature and high pressure.
109
Enthalpy of a gas depends upon its
temperature
110
When dilute aqueous solutions of two salts are mixed, the process is associated with
increase in temperature.
111
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.
112
Chemical engineering thermodynamics is concerned with the __________ in/of chemical processes.
energy transformation from one form to the another
113
An isolated system can exchange __________ with its surroundings.
neither matter nor energy
114
Requisites of a reversible process is that the
friction in the system should be absent.
115
Fugacity is most helpful in
representing actual behaviour of real gases.
116
The energy of activation of exothermic reaction is
not possible to predict.
117
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
118
In the reaction; N2 + O2 (1) 2NO, increasing the pressure will result in
no change in equilibrium condition.
119
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
120
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.
121
When a gas is subjected to adiabatic expansion, it gets cooled due to
energy spent in doing work.
122
Joule-Thomson effect i.e., a throttling process is a constant __________ process.
enthalpy
123
In the equation, PV^n = Constant, if the value of n = 0, then it represents a reversible __________ process.
isobaric
124
Work done in an adiabatic process between two states depends on the
end states only
125
The number of degree of freedom for an azeotropic mixture of ethanol and water in vapour-liquid equilibrium, is
1
126
The internal energy of an ideal gas is a function of its __________ only.
temperature
127
At constant temperature and pressure, for one mole of a pure substance, the ratio of the free energy to the chemical potential is
one
128
The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition.
Gibbs free energy
129
Work done is a
path function
130
Extensive properties of a thermodynamic system depend upon the __________ of the system.
mass
131
Near their critical temperatures, all gases occupy volumes __________ that of the ideal gas.
less than
132
The free energy change for a chemical reaction is given by (where, K = equilibrium constant)
-RT lnK
133
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
134
In the reaction, H2 +I2 ⇌ 2HI, addition of an inert gas will
not effect the equilibrium conditions
135
What is the number of degrees of freedom for liquid water in equilibrium with a mixture of nitrogen and water vapor ?
2
136
The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called the __________ temperature.
Boyle
137
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
138
All gases above its inversion temperature, in a throttling process will show
a heating effect.
139
First law of thermodynamics is mathematically stated as
dQ = dE + dW
140
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.
141
Translational kinetic energy of molecules of an ideal gas is proportional to (where, T = absolute temperature of the gas )
T
142
Equation which relates pressure, volume and temperature of a gas is called the
equation of state
143
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.
d. all (a), (b) and (c).
all of these
144
The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called __________ temperature.
Boyle
145
For a single component two phase mixture, the number of independent variable properties are
one
146
__________ law of thermodynamics ascertains the direction of a particular spontaneous process.
Second
147
At normal boiling point, molar entropy of vaporisation is __________ Joule/K°.mole.
92
148
For an ideal solution, the value of activity co-efficient is
1
149
The expression, nCv(T2 - T1), is for the __________ of an ideal gas.
work done under adiabatic condition
150
Which of the following is a widely used refrigerant in vapour compression refrigeration system (using large centrifugal compressor)?
a. Freon
b. Liquid sulphur dioxide
c. Methyl chloride
d. Ammonia
Freon
151
Internal energy is equal to the heat absorbed in case of a/an __________ process.
constant volume
152
The first law of thermodynamics is a restatement of the law of conservation of
mass
153
Joule-Thomson co-efficient for a perfect gas is
positive
154
In an adiabatic process, the
heat transfer is zero.
155
A nozzle is a device, which
increases kinetic energy and decreases pressure.
156
Duringthe phase transition, __________ changes.
volume
157
The work done in an adiabatic change in a particular gas depends upon changes in the __________ only.
temperature
158
In an isothermal process on an ideal gas, the pressure increases by 0.5 percent. The volume decreases by about __________ percent.
0.5
159
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)^(Δx), when Δx is negative
(atm)^(Δx), when Δx is positive
Dimensionless, when Δx = 0
(atm)^(Δx2), when Δx > 0
(atm)^(Δx2), when Δx > 0
160
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 non-flow process under isothermal condition is the change in Helmholtz free energy.
d. all (a), (b) and (c)
all of these
161
Partial molal quantities are important in the study of
non-ideal mixtures
162
Number of degrees of freedom for a three phase system in equilibrium comprising of three non-reacting chemical species is
2
163
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.
164
Enthalpy 'H' is defined as
H - E = PV
165
One ton of refrigeration is defined as the heat rate corresponding to melting of one ton of ice in one
day
166
__________ functions are exemplified by heat and work.
Path
167
In an irreversible process
Tds - dE + dW< 0
168
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
169
The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is
R loge 4
170
PVγ = Constant (where, γ = Cp/Cv) is valid for a/an __________ process.
adiabatic
171
Claude gas liquefaction process employs cooling
by expansion in an engine.
172
Which of the following will increase the volume of a real gas by four times ?
a. Doubling the absolute temperature as well as pressure of the gas.
b. Reducing pressure to one fourth at constant temperature.
c. Reducing temperature to one fourth at constant pressure.
d. Reducing the temperature to half and doubling the pressure.
Reducing pressure to one fourth at constant temperature.
173
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.
174
The equation, PV = nRT, is best obeyed by gases at
low pressure & high temperature.
175
Which of the following liquid metals has the highest thermal conductivity ?
a. Molten sodium
b. Molten lead
c. Mercury
d. Molten potassium
Molten sodium
176
Which of the following has the least thermal efficiency ?
a. Steam engine
b. Carnot engine
c. Diesel engine
d. Otto engine
Steam engine
177
Joule-Thomson Co-efficient at any point on the inversion curve is
0
178
Number of components (C), phase (P) and degrees of freedom (F) are related by Gibbs phase rule as
P + F - C = 2
179
The value of Cp & Cv respectively for monoatomic gases in Kcal/kg Mole . °K are
5 & 3
180
What is the number of degrees of freedom for liquid water in equilibrium with a mixture of nitrogen and water vapor ?
2
181
In case of a close thermodynamic system, there is __________ across the boundaries.
no mass transfer but heat transfer
182
During a reversible isothermal expansion of an ideal gas, the entropy change is
+ve
183
As the temperature is lowered towards the absolute zero, the value of (1), then approaches
zero
184
Which of the following is not affected by temperature changes ?
a. Fugacity
b. Activity co-efficient
c. Free energy
d. None of these
None of these
185
For an ideal gas, the activity co-efficient is
unity at all pressures.
186
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
187
Generation of heat by friction is an example of a/an __________ change.
irreversible
188
A domestic refrigerator has a/an __________ cooled condenser.
air
189
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
190
If we increase the pressure on a substance (which is at its triple point), then the triple point
remains unchanged
191
Free energy
a. decreases in all spontaneous (or irreversible) processes.
b. change during a spontaneous process has a negative value.
c. remains unchanged in reversible processes carried at constant temperature and pressure.
d. all (a), (b) and (c).
all of these
192
"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
193
Fugacity is a measure of the
escaping tendencies of the same substance in different phases of a system.
194
The quantitative effect of temperature on chemical equilibrium is given by the
Vant-Hoff equation.
195
For an irreversible process involving only pressure-volume work
(dF)T, p <0
196
Ideal refrigeration cycle is
same as reverse Carnot cycle.
197
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
198
The enthalpy change when ammonia gas is dissolved in water is called the heat of
solution
199
The value of Joule-Thomson co-efficient, in case where cooling occurs after the throttling process is
+ve
200
The specific heat of saturated water vapour at 100°C is
-ve
201
For a multicomponent system, the term chemical potential is equivalent to the
partial molar free energy.
202
The change in Gibbs freee energy for vaporisation of a pure substance is
zero
203
Critical compressibility factor for all substances
are more or less constant (vary from 0.2 to 0.3).
204
What is the degree of freedom for two mis-cible (non-reacting) substances in vapor-liquid equilibrium forming an azeotrope ?
2
205
For a given substance at a specified temperature, activity is __________ to fugacity.
directly proportional
206
In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in
enhanced COP.
207
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
208
In an ideal refrigeration cycle, the change in internal energy of the fluid is
zero
209
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.
210
The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is
less
211
The unit of fugacity is the same as that of the
pressure
212
Filling of gas from a high pressure cylinder into small bottles is an example of a/an __________ process.
unsteady
213
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.
214
At the critical point of a substance
a. the surface tension vanishes.
b. liquid and vapour have the same density.
c. there is no distinction between liquid and vapour phases.
d. all (a), (b) and (c).
all of these
215
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
216
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
217
y = specific heat ratio of an ideal gas is equal to
a. Cp/Cv
b. Cp/(CP-R)
c. 1 + (R/CV)
d. all (a), (b) and (c)
all of these
218
Gibbs free energy of a pure fluid approaches __________ as the pressure tends to zero at constant temperature.
minus infinity
219
As the entropy of the universe is increasing, day by day, the work producing capacity of a heat engine is
decreasing
220
An irreversible process
yields an amount of work less than that of a reversible process.
221
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
222
Free energy change of mixing two liquid substances is a function of the
a. concentration of the constituents only.
b. quantities of the constituents only.
c. temperature only.
d. all (a), (b) and (c).
all of these
223
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
224
The total change in the enthalpy of a system is independent of the
number of intermediate chemical reactions involved.
225
Number of phases in a colloidal system are
2
226
Free energy changes for two reaction mechanism 'X' and 'Y are respectively - 15 and - 5 units. It implies that X is
faster than Y
227
Vapour which is at a pressure smaller than the saturation pressure for the temperature involved is called a __________ vapour.
superheated
228
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
229
The kinetic energy of gas molecule is zero at
-273°C
230
Which of the following is not an intensive property ?
a. Volume
b. Density
c. Temperature
d. Pressure
Volume
231
The necessary and sufficient condition for equilibrium between two phases is
the chemical potential of each component should be same in the two phases.
232
Specific volume of an ideal gas is
the reciprocal of its density.
233
Pick out the extensive property out of the following.
a. Surface tension
b. Free energy
c. Specific heat
d. Refractive index
Free energy
234
Entropy change of the reaction, H2O(liquid) H2O(gas), is termed as the enthalpy of
vaporisation
235
Which law of the thermodynamics provids basis for measuring the thermodynamic property ?
Zeroth law
236
Gibbs free energy per mole for a pure substance is equal to the
chemical potential
237
Gibbs free energy at constant pressure and temperature under equilibrium conditions is
minimum
238
With increase in pressure (above atmospheric pressure), the Cp of a gas
increases
239
A change in state involving a decrease in entropy can be spontaneous, only if
it is exothermic.
240
__________ calorimeter is normally used for measuring the dryness fraction of steam, when it is very low.
A combination of separating & throttling
241
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
242
For a constant volume process
dE = CvdT
243
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.
244
The equation DU = Tds - PdV is applicable to infinitesimal changes occuring in
a closed system with changes in composition.
245
Heat is added at constant temperature in an ideal __________ cycle.
Stirling
246
Pick out the correct equation relating 'F' and 'A'.
a. F = A + PV
b. F = E + A
c. F = A - TS
d. F = A + TS
F = A + PV
247
In a reversible process
Tds = dE + dW
248
Cv for an ideal gas
is independent of both pressure and volume.
249
In a homogeneous solution, the activity co-efficient of a component depends upon the
a. pressure
b. composition
c. temperature
d. all (a), (b) and (c)
all of these
250
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.
251
With increase in compression ratio, the efficiency of the otto engine
increases
252
The chemical potential of any constituent of an ideal solution depends on the __________ of the solution.
a. temperature
b. pressure
c. composition
d. all (a), (b) and (c)
all of these
253
Fugacity and pressure are numerically equal, when the gas is
in ideal state
254
Refrigerants commonly used for domestic refrigerators are
ethyl chloride or methyle chloride
255
Absolute zero temperature signifies the
temperature of the heat reservoir to which a Carnot engine rejects no heat.
256
Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.).
Gibbs free energy
257
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.
258
For an exothremic reaction
both ΔH and ΔE are negative.
259
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.
260
The shape of T-S diagram for Carnot Cycle is a
rectangle
261
For an isothermal process, the internal energy of a gas
remains unchanged
262
In the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process.
isothermal
263
For the gaseous phase chemical reaction, C2H4(g) + H2O(g) ⇌ C2H5OH(g), the equilibrium conversion does not depend on the
a. steam to ethylene ratio.
b. temperature.
c. pressure.
d. none of these.
none of these.
264
The first law of thermodynamics is a statement of conservation of
energy
265
"Dry ice" is
solid carbon dioxide
266
Which of the following non-flow reversible compression processes require maximum work ?
a. Adiabatic process
b. Isothermal process
c. Isobaric process
d. All require same work
Adiabatic process
267
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.
268
"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.
269
Sound waves propagation in air exemplifies an __________ process.
adiabatic
270
For equilibrium process (i.e. reversible) in an isolated system
ds = 0
271
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
272
With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure
increases
273
For an ideal gas, the enthalpy
is independent of pressure.
274
Efficiency of a heat engine working on Carnot cycle between two temperature levels depends upon the
two temperatures only.
275
In Joule-Thomson porous plug experiment, the
enthalpy does not remain constant.
276
A Carnot cycle consists of the following steps :
Two isothermals and two isentropics.
277
For a cyclic process, a fixed ratio between heat and work
always exists
278
Which of the following is not a common refrigerant ?
Ethylene
279
The most important application of distribution law is in
liquid extraction
280
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.
281
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
282
Gibbs free energy of mixing at constant pressure and temperature is always
- ve
283
If two gases have same reduced temperature and reduced pressure, then they will have the same
a. volume
b. mass
c. critical temperature
d. none of these
none of these
284
Which of the following is an extensive property of a system ?
a. Heat capacity
b. Molal heat capacity
c. Pressure
d. Concentration
Heat capacity
285
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
286
Cp - Cv = R is valid for __________ gases.
ideal
287
At a given temperature, the volume of a gas dissolved in a solvent __________ with increase in pressure.
remains unchanged
288
Which is an example of closed system ?
a. Air compressor
b. Lquid cooling system of an automobile
c. Boiler
d. None of these
Lquid cooling system of an automobile
289
Melting of wax is accompanied with __________ in entropy.
increase
290
Work done in case of free expansion is
zero
291
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
292
During adiabatic expansion of gas
none of these.
293
Which of the following has the minimum value of COP for a given refrigeration effect?
a. Reverse Carnot cycle.
b. Ordinary vapour-compression cycle.
c. Vapour-compression process with a reversible expansion engine.
d. Air refrigeration cycle.
Air refrigeration cycle.
294
__________ decreases during adiabatic throttling of a perfect gas.
Pressure
295
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.
296
Tea kept in a thermos flask is vigorously shaken. If the tea is considered as a system, then its temperature will
increase
297
Change of heat content when one mole of compound is burnt in oxygen at constant pressure is called the
heat of combustion
298
Clausius - Clayperon equation is applicable to __________ equilibrium processes.
a. solid-vapor
b. solid-liquid
c. liquid-vapor
d. all (a), (b) and (c)
all of these
299
In which of the following reaction equilibria, the value of equilibrium constant Kp will be more than is Kc ?
a. 2HI H2 + I2
b. N2O4 2NO2
c. 2SO2 + O2 2SO3
d. none of these
N2O4 ⇌ 2NO2
300
After throttling, gas temperature
decreases
301
The chemical potential for a pure substance is __________ its partial molal free energy.
equal to
302
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.
303
COP of a refrigerator drawing 1 kW of power per ton of refrigeration is about
3.5
304
The number of degrees of freedom for a mixture of ice and water (liquid) are
1
305
On opening the door of an operating refrigerator kept in a closed room, the temperature of the room will
increase
306
Domestic refrigerator usually works on the __________ refrigeration cycle.
absorption
307
Gibbs-Duhem equation
states that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure.
308
Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is
2
309
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
310
"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
311
The internal energy of an ideal gas does not change in a reversible __________ process.
isothermal
312
A/an __________ system is exemplified by a vessel containing a volatile liquid in contact with its vapor.
open
313
In a P-V diagram (for an ideal gas), an isothermal curve will coincide withan adiabatic curve (through a point), when
Cp = Cv
314
For an ideal gas, the chemical potential is given by
RT dlnP
315
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
316
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.
317
Entropy change for an irreversible isolated system is
> 0
318
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
319
The unit of equilibrium constant of a chemical reaction is the same as that of
a. molar concentration
b. temperature
c. internal energy
d. none of these
none of these
320
Which of the following equations is obtained on combining 1st and 2nd law of thermodynamics, for a system of constant mass?
a. dE = Tds - PdV
b. dQ = CvdT + PdV
c. dQ = CpdT + Vdp
d. Tds = dE - PdV
dE = Tds - PdV
321
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
322
Entropy is a/an
a. state function
b. macroscopic property
c. extensive property
d. none of these
none of these
323
At triple point (for one component system), vapour pressure of solid as compared to that of liquid will be
same
324
Which of the following is not correct for a reversible adiabatic process ?
a. TV^(γ-1) = constant
b. p^(1-γ).T^Y = constant
c. PV^γ = constant
d. none of these
none of these
325
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)
326
Throttling (Joule-Thomson effect) process is a constant __________ process.
enthalpy
327
Boiling of liquid is accompanied with increase in the
vapor pressure.
328
Change of state namely evaportation condensation, freezing and melting is an __________ process.
isothermal
329
Which of the following is not an equation of state?
Clausius Clayperon equation
330
A gas shows deviation from ideal behaviour at
low temperature and high pressure.
331
The difference between isothermal compressibility and adiabatic compressibility for an ideal gas is
+ve
332
The expression for entropy change given by, ΔS = - nR ln (P2/P1), holds good for
reversible isothermal volume change.
333
With increase in temperature, the internal energy of a substance
increases
334
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.
335
For a constant pressure reversible process, the enthalpy change (ΔH) of the system is
integ Cv.dT
336
The work done in isothermal compression compared to that in adiabatic compression will be
more
337
For organic compounds, group contribution method can be used for the estimation of
critical properties.
338
Specific __________ does not change during phase change at constant temperature and pressure.
Gibbs energy
339
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.
340
Heat evolved/absorbed during conversion of a substance from one allotropic form to another is termed as the heat of
transition
341
What happens in a reversible adiabatic compression ?
Heating occurs
342
Sublimation temperature of dry ice (solid CO2) is __________ °C.
-78
343
If atmospheric temperature and dew point are nearly equal, then the relative humidity is
almost 100%
344
Entropy change in case of reversible adiabatic process is
zero
345
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
346
The efficiency of an Otto engine compared to that of a diesel engine, for the same compression ratio will be
more
347
Mollier chart is a __________ plot.
enthalpy vs entropy
348
Variation of equilibrium pressure with temperature for any two phases of a given substances is given by the __________ equation.
Clayperon
349
Pick out the undesirable property for a good refrigerant.
a. high thermal conductivity
b. low freezing point
c. large latent heat of vaporisation
d. high viscosity
high viscosity
350
Isotherm on an enthalpy-concentration diagram, for an ideal solution will be a
straight line
351
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.
352
Melting of ice is an example of an __________ process.
isothermal
353
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
354
Rotary lime kiln is an example of a/an __________ system.
open
355
Heat of reaction is
dependent on both pressure and temperature.
356
What happens in a reversible adiabatic expansion process ?
Cooling takes place.
357
Degree of freedom of a system consisting of a gaseous mixture of H2 and NH3 will be
3
358
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
359
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 the universe tends to a maximum.
360
Fugacity co-efficient of a substance is the ratio of its fugacity to
activity co-efficient
361
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
362
As the time is passing, entropy of the universe
is increasing
363
Which of the following processes can not be made reversible even under ideal condition of operation?
a. Free expansion of a gas.
b. Compression of air in a compressor.
c. Expansion of steam in a turbine.
d. all (a), (b) & (c).
Free expansion of a gas.
364
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
365
Which of the following identities can be most easily used to verify steam table data for superheated steam.
a. (∂T/∂V)S = (∂p/∂S)V
b. (∂T/∂P)S = (∂V/∂S)P
c. (∂P/∂T)V = (∂S/∂V)T
d. (∂V/∂T)P = -(∂S/∂P)T
(∂V/∂T)P = -(∂S/∂P)T
366
In the equation PVn = constant, if the value of n = y = Cp/Cv, then it represents a reversible __________ process.
isentropic
367
The ammonia synthesis reaction represented by N2 + 3H2 ⇌ 2NH3 ; ΔH = - 22.4 kcal, is
exothermic
368
With increase in temperature, the atomic heat capacities of all solid elements
increases
369
The temperature at the eutectic point of the system is the __________ temperature that can be attained in the system.
lowest
370
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
371
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.
372
An isentropic process is carried out at constant
volume
373
All gases except __________ shows a cooling effect during throttling process at atmospheric temperature and pressure.
hydrogen
374
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.
375
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.
376
Compressibility factor-reduced pressure plot on reduced co-ordinates facilitates
use of only one graph for all gases.
377
Which of the following is not an intensive property ?
a. Molar heat capacity
b. Internal energy
c. Viscosity
d. None of these
Internal energy
378
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.
379
Gibbs phase rule finds application, when heat transfer occurs by
condensation
380
Absorption/evolution of heat during conversion of a substance from one allotropic form to another is termed as the heat of
transition
381
Ideal gas law is applicable at
high T, low P
382
Reduced pressure of a gas is the ratio of its
pressure to critical pressure.
383
For a reversible process involving only pressure-volume work
(dF)T, p = 0
384
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)
385
Entropy change for an irreversible process taking system and surrounding together is
> 0
386
In a homogeneous solution, the fugacity of a component depends upon the
a. pressure
b. composition
c. temperature
d. all (a), (b) and (c)
all of these
387
For an incompressible fluid, the __________ is a function of both pressure as well as temperature.
enthalpy
388
One ton of refrigeration capacity is equivalent to the heat removal rate of
200 BTU/minute
389
What is the degree of freedom for a system comprising liquid water equilibrium with its vapour ?
1
390
Equilibrium constant of a reaction varies with the
temperature.
391
Third law of thermodynamics is concerned with the
value of absolute entropy.
392
Claude's liquefaction process employs the cooling of gases by
expansion in an engine
393
Gibbs free energy (F) is defined as
F = H - TS
394
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.
395
The second law of thermodynamics states that
none of the above.
396
Internal energy of an ideal gas
a. increases with increase in pressure.
b. decreases with increase in temperature.
c. is independent of temperature.
d. none of these.
none of these.
397
A refrigerator works on the principle of __________ law of thermodynamics.
second
398
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.
399
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.
400
Which of the following is affected by the temperature ?
a. Fugacity
b. Activity co-efficient
c. Free energy
d. All (a), (b) & (c)
all of these
401
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
402
The adiabatic throttling process of a perfect gas is one of constant enthalpy
which can be performed in a pipe with a constriction.
403
For spontaneous changes in an isolated system (S = entropy)
ds > 0
404
A gas performs the maximum work, when it expands
isobarically
405
There is a change in __________ during the phase transition.
volume
406
Which of the following is Virial equation of state?
PV = A + B/V + C/V^2 + D/V^3 + ...
407
Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is
zero
408
First law of thermodynamics deals with the
direction of energy transfer.
409
Henry's law is closely obeyed by a gas, when its __________ is extremely high.
a. pressure
b. solubility
c. temperature
d. none of these
none of these
410
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.
411
A solid is transformed into vapour without going to the liquid phase at
triple point
412
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
413
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
414
For a thermodynamic system containing 'x' chemical species, the maximum number of phases that can co-exist at equilibrium is
x + 2
415
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.
416
Standard temperature and pressure (S.T.P.) is
0°C and 750 mm Hg
417
Normal temperature and pressure (N.T.P.) corresponds to
20°C and 760 mm Hg.
418
The minimum number of phases that can exist in a system is
1
419
Enthalpy changes over a constant pressure path are always zero for __________ gas.
a perfect
420
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
421
__________ does not change during phase transformation processes like sublimation, melting & vaporisation.
Gibbs free energy
422
Which one is true for a throttling process ?
a. A gas may have more than one inversion temperatures.
b. The inversion temperature is different for different gases.
c. The inversion temperature is same for all gases.
d. The inversion temperature is the temperature at which Joule-Thomson co-efficient is infinity.
The inversion temperature is different for different gases.
423
Choose the condition that must be specified in order to liquify CO2 (triple point for CO2 is - 57°C and 5.2 atm).
a. Pressure must be kept below 5.2 atm.
b. Temperature must be kept above - 57°C.
c. Pressure must be kept below 5.2 atm. and temperature must be kept above 57°C.
d. Pressure and temperature must be kept below 5.2 atm. and - 57°C respectively.
Pressure and temperature must be kept below 5.2 atm. and - 57°C respectively.
424
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
425
Lenz's law results from the law of conservation of
energy
426
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
427
Throttling process is a/an __________ process.
irreversible and constant enthalpy
428
The main feature of Carnot refrigeration cycle is that, it
accomplishes the reverse effect of the heat engine.
429
Charles' law for gases states that
V/2 = Constant
430
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
431
Helmholtz free energy (A) is defined as
A = E - TS
432
As pressure approaches zero, the ratio of fugacity to pressure (f/P) for a gas approaches
unity
433
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
434
The variation of heat of reaction with temperature at constant pressure is given by the __________ law.
Kirchoffs
435
At absolute zero temperature, the __________ of the gas is zero.
volume
436
Which of the following equations is used for the prediction of activity co-efficient from experiments ?
a. Van Laar equation
b. Margules equation
c. Wilson's equation
d. all (a), (b) and (c)
all of these
437
Entropy of a substance remains constant during a/an __________ change.
reversible adiabatic
438
Gases are cooled in Joule-Thomson expansion, when it is __________ inversion temperature.
below
439
PVy = constant, holds good for an isentropic process, which is
reversible and adiabatic.
440
In the reaction, C + O2 → CO2 ; ΔH = - 94 kcal. What is the heat content (enthalpy)of O2?
zero
441
When a system is in equilibrium for all possible processes, the differential or finite change of entropy is
< 0
442
A system is said to be at equilibrium, if the entropy of the system has reached __________ value.
maximum
443
In the equation, PV^n = constant, if the value of n = ± ∞, then it represents a reversible __________ process.
isometric
444
A system in which there is exchange of energy but not of mass, is called a/an __________ system.
closed
445
The point at which all the three (solid, liquid and gas) phases co-exist, is known as the __________ point.
triple
446
In an ideal gas mixture, fugacity of a species is equal to its
partial pressure
447
The third law of thermodynamics states that the
heat capacity of a crystalline solid is zero at absolute zero temperature.
448
Consider the reaction, C + O2 ⇌ CO2 ;ΔH = - 94 kcal. What will be the value of ΔH for the reaction CO2 C + O2 ?
+ 94 kcal
449
Which is not a state function ?
a. Specific volume
b. Work
c. Pressure
d. Temperature
Work
450
For an ideal liquid solution, which of the following is unity ?
a. Activity
b. Fugacity
c. Activity co-efficient
d. Fugacity co-efficient
Activity co-efficient
451
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
452
In case of an __________ process, the temperature of the system increases.
adiabatic compression
453
Cp of a gas at its critical temperature and pressure
equals 1 kcal/kmol °K.
454
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
455
Which of the following is true for Virial equation of state ?
a. Virial co-efficients are universal constants.
b. Virial co-efficients 'B' represents three body interactions.
c. Virial co-efficients are function of temperature only.
d. For some gases, Virial equations and ideal gas equations are the same.
Virial co-efficients are function of temperature only.
456
Molar heat capacity of water in equilibrium with ice at constant pressure is __________ Kcal/kg mole . °K
∞
457
A gas can be liquified by pressure alone only, when its temperature is __________ its critical temperature.
less than or equal to
458
For an ideal gas, the internal energy depends upon its __________ only.
temperature
459
Compound having large heat of formation is
more stable.
460
Second law of thermodynamics is concerned with the
direction of energy transfer.
461
Trouton's ratio of __________ liquids is calculated using Kistyakowsky equation.
non-polar
462
The number of degrees of freedom at the triple point of water is
0
463
The heat capacities for the ideal gas state depend upon the
temperature
464
Internal energy of an element at 1 atm and 25° C is __________ kcal/kg.mole.
0
465
In an ideal refrigeration cycle, the change in internal energy of the fluid is
0
466
Refrigeration cycle
involves transfer of heat from low temperature to high temperature.
467
In case of a reversible process (following pvn = constant), work obtained for trebling the volume (v1 = 1 m3 and v2 3 m3 ) is max imum, when the value of 'n' is
0
468
What is the value of Joule-Thomson co-efficient for an ideal gas ?
0
469
Cv for an ideal gas
is independent of both pressure and volume.
470
The equation, Cp - Cv = R, is true for __________ gas.
only ideal
471
Heat of formation of an element in its standard state is
0
472
The Joule-Thomson co-efficient is defined as (∂T/∂P)H. Its value at the inversion point is
0
473
4 kg moles of an ideal gas expands in vacuum spontaneously. The work done is
0
474
Heat of reaction at constant volume is identified with __________ change.
internal energy
475
For any system, what is the minimum number of degrees of freedom?
0
476
Which of the following behaves most closely like an ideal gas ?
He
477
Degree of freedom of the system ice-water-vapour will be
0
478
Degree of freedom of the system ice-water-vapour will be
0
